I'm a mechanical engineer in the motorcycle industry, and this is video is 100% exactly right. I have also been racing motocross for over 10 years. Happy to see some media outlets offering actual information about motorcycle engineering to clear up all of the wive's tales.
Glad that you mentioned seal failure. Mine went out in Jacksonville, Florida last March. Bathed both calipers with fork oil - as in puddle on the ground. Made it the 750 or so miles from JAX back home to northern Virginia with NO front brakes. Whee.
Monoshock is better for track riding and cornering and can be adjusted for variety of settings.Double shocks are better for offroading and load bearing and are better for bumpy roads as they can take on heavier weights than monoshock.But dual shocks don't lend themselves well for cornering as well as monoshocks do.
more pivot points in dual shocks means its geometry is more susceptible to moving in undesired ways. Mono shock makes it rigid by having just one coupling point with the shock.
Nice video. Aircraft shock struts, which are very similar to telescopic motorcycle forks, have always had the outer cylinder on top and the inner piston on the bottom. So, what is right-side-up on an airplane is called upside-down on a motorcycle. BTW, aircraft struts do not have internal springs, but rely on compressed nitrogen gas to bear the weight of the aircraft. Here is what might sound strange: if you see a mechanic adding or releasing nitrogen from a strut, he is changing the extension of the strut, but not the gas pressure in it. The only way to change the pressure is to change the load on the strut.
I got a 43mm conventional right-side forks on my bike and for street riding, touring and occasionally track days it performs quite well, the only upgrade I did with them is installing a good set of quality progressive springs with the right fork oil density and a fully adjustable rear monoshock, a suspension specialist did the job on my bike beautifully and it performs really well.
Additionally, USD-Forks tend to have less unsprung masses than similar sized conventional forks. This may help increase riding comfort and may provide better front tire traction, especially on bumpy roads or on the track, if set up properly. Keep up the good work, Greetings from Bavaria!
I think it's rotational mass that actually has the greatest benefit... upside-down forks are better than normal but you will feel lighter brakes, lighter rims far more than if you swapped upside-down forks for conventional... since the suspension itself it technically un-sprung, the weight of the components is what matters, not it's orientation... and the upside-down forks may or may not carry an additional benefit in that category due to the perception of upside-down forks feeling stiffer which may also lead to the perception of lightness since there is less flex overall.
Conventional forks are more suited for off-road riding because the fork stanchions get battered more with rocks/pebbles, causing more abrasion of the fork seals by the increased roughness. And gaiters down low would collect water through their breather holes from streams and puddles.
Bulu bhaina jay Jagannatha! Upside down forks kebala track use pai better. High end motorcycle gudika jouthire conventional forks rahuchi seguda madhya bhari stiff eka. Especially offroading re oil seal herika crack karibara besi chance rahiba hard core offroading karile tenukari conventional setup thik rahiba. Janichi apanakara 3barsa tala comment hele dekhili ta bhabili reply kari diye. 😁 Khusi lagila apana madhya emiti videos dekhuchanti. Have a nice day sir take care❤️
The difference in unsprung mass is minimal in the real context. USD forks are fashionable because they can look like what are on racing bikes. In street riding, the real world, there are cheap, flexy USDs and very good traditional forks that are stiffer. Two problems with USDs: the slider is exposed lower, more prone to chipping and damage, and when the seals fail, they dump out oil on the brakes, and when it comes time to fix all that, they are more complex. Companies are making cheapo USDs anodized gold , i.e. Fauxlins, they are crap. looking at you, Yamaha. It's a fashion choice, like petal rotors. It would make sense to put neoprene boots on USD fork sliders, but that's currently not cool.
It’s cool to me. I have an SV650, conventional forks, and I’m not swapping them. But I would like to know what sleeve you’d recommend to cover where the dirt is able to get in. Thank you
My brother built a model for a Revell model contest in 1976, based on Revell's Roger DeCoster Suzuki MX model... He couldn't leave well enough alone, though and proceeded to design a bike that did things that nobody was doing in 1976... including inverted forks. Finished it a month before the deadline, because we were going to be in Spain when the entry was due. Wild details: Working suspension (F & R) Inverted gas fork design (10+ years before this design showed up in production) Laid-down rear shock absorbers Underseat gas tank (lower CG) Liquid cooled (vs air) Radiator behind mesh number plate "Snail" exhaust pipe Airbox between legs, where gas tank usually is Padded seat Working rear brake pedal (actuates spring loaded rod to rear wheel) The funniest part of the story is that, after winning his local region, his model was sent to the national competition, where 1st prize winner would receive a custom Datsun Li'l Hustler pickup with a then-new Suzuki RM125 in the bed... 1st prize went to a VERY faithfully built and beautifully detailed (mud splatters, etc.) rendition of the DeCoster 400, and 2nd to my brother. 2nd prize was a helmet. See photo of 1976 model: uploads.disquscdn.com/images/5b396f42e1fc200370a51ebf2d06e3aeb1fcc7221ab6865e550ee5522c874f6a.jpg
Yes. That's why there are fork gaiters - to protect the stanchion from rust from road salt and from chips/dents from rocks that cause abrasion of the rubber seal. Gaiters look Old School and nerdy, but they provide a definite protection for the bike.
Nice explanation.. Unless you're pushing the bike ( street or in the woods/dirt trails ) It seems to me to be almost a 50/50 deal for the average rider. A big factor you pointed out is the potential for the seals to leak on the brake components. That's worthy of consideration...
Fork guards remove a large part of that issue. Motocross/enduro all run upside down forks and it works really well. Add a proper wrap-around fork guard if you are doing some more extreme stuff and you'll be set. A positive on the upside down one is that the scraper pushes the dirt down and it stays there, while a conventional fork is more likely to have dirt buildup on the scraper. I know it's not a totally fair comparison, but my 1980's conventional fork on a road-going machine tends to be more gunked up than my 00's and 10's offroad machines. (including pure motocross and dual sport)
@@Simon-eh5ez upside down isn't always better look at the late 90s rm's. those things have amazing Force way better than the upside down forks on the other dirt bikes at the time.
Love the video's from MC Garage.Clear and easy to understand explanation about how bikes and their components work. Greetings from the Netherlands,Theo.
You didn't cover the single biggest reason why inverted is better, and it's the same reason why most vehicle hood and trunk lift supports are mounted so that they "rest" in the inverted position. It causes all the shock oil to collect against the seal(s), keeping them wet and lubricated. This prolongs the life of those seals, meaning fewer failures and less maintenance.
I had Suzuki GT250 engineered by the lads at college in 1977... Aside from engine and carb mods with some reed valves made and fitted, they machined the alloy legs, made triple trees to fit, and fitted twin disc mounts that they'd made... It revved to 10,500 instead of about 7,000 and seldom needed the very long 6th gear. The forks didn't leak at all... Just the usual slight sheen as seen on normal configuration... I finished it in matt black and white lettering and graphics. I loved that bike...
mrvwbug44 You mean USDs have more unsprung mass, as the fork tubes are heavier than the slider which is usually made of aluminum. On the other hand some people say that USDs benefit from that lower CoG. But as Ari suggested, this weight difference has a minor effect, compared to stiffness difference.
Sprung weight is only affected once the weight drops lower than the centre of the wheels. Aka lower frame rails, crankcase, transmission etc... As far as the forks are concerned is 100% sprung weight
+Moggy1000 anything that is moving along with the wheel is unsprung load. its not about the position of it. if you put a sack of potatoes on the front mudguard, the front wheel will have a really hard time to follow the road bumps, which makes handling worse. if you put that same sack of potatoes below the center of the wheel, it will have the same effect. it will still be an unsprung mass.
Very good explained. I am an average sporty driver and own some (classic) motocycles, some with upright forks, same with upsid-down forks. I never felt the difference between them ... best regards from Germany.
as far as I know upside down Forks were introduced for dirt bikes, since you can make longer damping ways with a smaller Fork and for a second reason very big normal forks have tube extending below the axle wich results in them grabbing dirt earlier when driving through deep ruts
Peter Griffin strange that trails bikes have reverted back to conventional I guess they help pop you up over obstacles easier then usd? No idea why just what I’ve noticed
Greetings Mr. Henning all kidding aside and as always I do enjoy your clips. 100% accurate information, yet this clip is different. I merely point this out due to the volume of audience. 1. The slider is the chrome slider with the stanchion being the outter anodized capped tube. stan·chion /ˈstan(t)SH(ə)n/ noun noun: stanchion; plural noun: stanchions an upright bar, post, or frame forming a support or barrier It's providing support for the slider. 2. You most certainly will feel the difference. Keeping in mind the many bikes with standard forks which will easily due 100mph and inherently some folks will reach that speed and experience the watusi.
It may sound weird to you but amount of grip have nothing to do with tyre width. Wide tyres and narrow tyres have same amount of grip. Forces involved in grip and traction are not that simple.
tyre width does not effect friction.its not about grip its about cooling (bigger surface faster cooling) and handling (for smooth counter steering) etc.
I ride a harley that i beat the hell out of and I had someone tell me the other day “i know someone whos selling an inverted front enf for $500! You should buy them!” I thought about it, but after this video, im happy with my regular forks with the heavy duty springs. Totally worth the money than to waste it on inverted forks.
Nice, Ari. You do good work. I'm pleased that you didn't muddy the question by launching into an "unsprung weight" discussion, which might be useful to Jorge but for me, waaay to much. Thanks.
3:12 What? Gravity ensures oil will run down on both fork types. Regardless of distance traveled, oil is just as likely to contaminate the brakes on both types of forks. You've totally missed the point in this issue; the conventional design has the inherent problem where water will find its way into the seal (again through gravity) and cause corrosion in the seal's steel support ring vulcanised inside the rubber. This in turn leads to more frequent leaks and replacement costs for the conventional forks. Every single bike restoration I've done on bikes with conventional forks has required replacement of leaking/corroded seals due to water ingress. This is a major advantage of the difference in design and the way you described the oil issue is irrelevant.
Moving masses are smaller on an usd-fork. That makes the wheel a bit faster following the bumpy surface of the road. But that's also a thing you may only notice on racetracks :)
Thanks for the sweet, simple and on point explanation. Any next smartass who's gonna keep arguing to me that upright fork vs inverted stanchion forks has no difference, I'll slap em with this video.
+Ari Henning you missed mentioning the unsprung weight factor. But I guess it's effective, as you said, only at the limits on a track. I haven't really been able to differentiate USD vs RSU on road conditions. Anyway, good video as always. A lot of other channels should know that making such short, precise videos is how info videos should be. Not some 15 min long ramble before getting to the point. Take a bow Motorcyclist Magazine.
I don't comment on UA-cam video's ofren, but I am really impressed with the way Ari covers the quick differences that are indisputable facts. He is so clearly un-biased and just down to share what can be covered without over-complicating the situation with irrelevant hyper performance squabbles. My favorite bike is an Honda MC22, it comes with conventional forks, they bend often after a crash and are very quick and easy to work on. I could change them to upside down forks but choose not to because in terms of performance the bikes that have upside-down forks in its class e.g. ZX2R don't merit mention due to that fact alone as its probably about 0.00005% of the whole pie in terms of why this guys faster than that guy. One thing that could have been touched on is that not only are conventional forks much easier to work on but they are much cheaper to replace and the only common time conventional forks bend is after a crash which upside-down forks are still very much susceptible to taking damage from. In short if you are not a contender in the TT or the GP/Superbikes/Supersports the direction your forks face in terms of performance is virtually irrelevant.
I once owned a 1982 GSX1100 Katana and the forks would twist when you counter steered at highway speeds, it was the freakiest feeling as you would move the bars and then the wheel would follow 1/2 second later
I think you had some issues with that particular fork then... I've had a GSX 1100 EF since 1988 (basically the same front fork, except for the PDF units instead of traditional anti dive units) - I've never had any (noticeable anyway) flexing of my fork because of this. The EF does have a stabilizer built into the front fender though; this might reduce the problem quite a bit, of course.
Honda Valkyrie uses a flat 6 cylinder motor. And Honda once used a 5 cylinder motor (RC211V) in their MotoGP bikes. Add these to the review suggestion please!
There isn't a versus, they all have different attributes in their engine configuration. who ever said there aren't dumb questions was probably a moron.
cylinders basically is replacement of your foot and foot pedal on bicycle. for example in order to move the bike we need certain amount of force, e.g 1 torque. for 1 cylinder, it's like a bike having only 1 pedal, we must give 1 torque on single leg for single rotation. while on 2 cylinders, it's mean having 2 pedals, the weight distributed each cylinders, if bike need 1 torque to move, then each cylinder only need contribute half torque. on 3 cylinders, each cylinder contribute 1/3 torque. and last 4 cylinders, each cylinders contribute 1/4 torque. now if we reverse, let's say each cylinder on 4 cylinders contribute same amount of torque like on 1 cylinder, then the machine produce 4 times more torque than 1 cylinders. ofc, this is just simple math, we must count the structure of the crankshaft, the diameter of the cylinders, height of cylinder head, and so on. but basically, more cylinders mean more torque, not speed but torque.
noface actually more cylinders provide more hp but not torque, few cylinder do produce more torque with the same displacement engine but with more cylinder. Because the engine with few cylinders have more stroke
@@siontheodorus1501 How come we just can't have an 8-cyl engine that goes to 20k RPM then? It would sound way better than anything else and the size of the pistons can be half that of a 4 cyl so the space can be nearly identical.
Also with an upside-down fork you can more easily measure the range of front suspension utilized by putting a zip tie on the rod and riding the bike. The tie will tell you if you're using the entire suspension by its position. Good for suspension adjustment on track days. Hope this makes sense.
One other benefit is that the upside down fork has less chrome parts open to the elements to cause premature seal wear in the first place, the conventional fork is open to the full front end's wind, rain, dirt and debris that could pit the chrome coating over time. Definite benefit right there.
Idea for a video: slightly controvertial. Piston arrangement. V-Twin vs Boxer vs Parellel vs inline vs v-Twin (transverse). The question this video will be seek to answer is "how does piston arrangement affect how power is transferred to the road and why some companies have stuck to one arrangement while other take a more product by product approach". This originally occurred to me when the new Africa twin was launch and there was a small fraction of rider who expected it to be V-twin like the original and not parallel.
I'd like to see +Ari Henning explaining something like this too. Crankshaft configuration and the benefits of each. 360° crankshafts, 180° crankshaft and 270° crankshaft V-engines, In-line engines and horizontally opposed.
Saif a parallel twin in my opinion beats a V-Twin any day much more smooth ER and faster revving. A four cylinder motorcycle twice as good as a 2 cylinder motorcycle but has disadvantage of its width and its weight!!! I really really really hate the. V twins
I had a 650 v-twin it had more torque and fun than my current 750cc inline four. So am scratching my head, as am not as advanced as the tech gurus here ...
The smaller stanchion parts mean less weight that needs to move up and down with the wheel. That’s the biggest reason for USD forks. You mention why a leaked seal could be worse but the other issue is that the sensitive surface is more exposed. It can get pitted with road debris and damage the seals since they are no longer protected by the bike’s fairings. This is why modern front fenders also partially cover the forks, which means the 2008-2012 Ninja 250 is faking it for a modern-looking front fender even though it has standard forks. ;)
If you are looking for comfort, you can choose the straight shock absorber, which will help you hold the road or take turns more easily. If you are traveling on mountain roads or are very fast and heavy, you can choose the reverse shock absorber. As a result, the shock absorber works with load and impact. Since the front wheel will be very light, shock absorbers are preferred depending on the type of motorcycle.
how can it have less unsprung weight when the moving part is made of heavy gauge steel while on normal forks the moving part is made from light weight alloy
I did the fork seal and bush on my crf250l in 10 minutes out in the countryside with only the honda toolkit and a discarded plastic bottle so yeah, theyre real hard to service
Great vid. Bottom line is- for MOST RIDING off track you will never know the difference.. Except that USD forks often have more damping adjustments. Both of my bikes have non-USD forks; one has no damping adjustments (sadly) and the other does. That's all that matters. PS- Yup, when I go to service my forks, IT'S A BREEZE. Try that with your USD's
This video is incorrect, pretty much end to end. The fork stiffness isn't the reason that USD forks are now preferred, nether is unsprung or sprung mass (both of which go up with USD forks) its because of fork bush loads. RWU forks simply used a larger diameter inner tube to improve stiffness, so the last performance bikes to use RWU forks used 46mm tubes not the almost universal 43mm that was transitioned to. RWU forks also only had an outer in the ballpark of 400mm long, from cast aluminium, which means that its substantially lighter than the nearly meter long piece of steel that is the inner tube, and thats before you take into account that the RWU outer also serves dual duty as a caliper mount bracket, whereas on USD there needs to be a complex bracket attached to the foot of the inner tube. So RWU are lighter than an equivalent USD for stiffness. The damping in the forks can also be exactly the same depending on what the manufacturer offers. The reason is because the distance between the fork bushes affects the loads that go through the bushes, because the fork carries a bending moment from any brake loads applied. This means that if you double the distance between the fork bushes you halve the friction, which substantially improves the damping performance of the fork under brakes. The whole "Set up and squeeze" technique of braking exists specifically because fork bushes load up and bind suspension, so if you don't gently apply the brakes then you won't have the suspension start travelling to a "settled" position before it gets locked out by loads. By comparison in USD forks the bushes are far less heavily loaded, and as a result you can be far more aggressive with brake onset and you'll also notice far better suspension performance under braking on the bike. This is critically important if you're doing any of your braking while you're tipping in, because the suspension effectively becomes stiffer due to the angle of the bike. Apart from anything else, USD forks are useful because they reduce the impact of poor brake application, panic braking... bikes end up skidding down the road because people grab un injudicious handful of brakes in an emergency, even when upright, this is why.
@@akshaysinghgirdhar He is not an engineer. I can tell that he also doesn't have much riding experienced compared to me. Im an engineer who has been racing motocross for over 10 years. On my vintage bike (not my main race bike), I rode with the stock conventional forks for one half of a season. I switched the forks out for a set of USD forks, and cornering drastically improved, regardless of braking. The front end was very bendy and vage feeling with the conventional forks. The USD forks made the bike corner just like a modern dirtbike. Even when you werent using the brakes. Braking was only barely effected when I switched to USD forks. The level of front end control now makes the old forks feel like wet noodles. No front wheel control EVER with conventional forks. With USD forks the front end does exactly what i tell it to.
@@sciencemilitia1853 You start by saying the original poster is not an engineer but you are, and the proceed to just post up an opinion without any explanation to back it up other than "I *feel* it's better". An engineer would mention the different lengths, materials, diameters, the oil itself etc of the forks and how all these things can affect their performance, only after all those factors have been ruled out could you say anything abut the orientation of the forks making them better or worse and not one of those other factors. You're not an engineer.
@@BigUriel The guy in the video already explained it all. Larger diameter tubes have higher bending strenth. That means less flex. When you compose the larger portion of the fork with the larger diameter tube, you get less total deflection (aka flex).
Slatteea Not as big as you'd think. Because the upper part of the fork on either design bears the greatest load, both are designed to be heavier there than on the bottom. A USD fork has heavy sliders and light stanchions, while RSU forks have light sliders and heavy stanchions. Strong up top, light down below.
The only issue you would have with the stress of a right side up fork being inferior to upside down forks is if they were known for buckling under hard braking. I have never had an issue with my forks buckling on any bike I have ever ridden and a few of them I did some pretty hard road racing with. For the average motorcycle rider that loves the road, I seriously doubt this is of concern at all.
"Why Are Inverted Forks So Good?" because that lose more often the oil (and once start lose had to get fixed) so you make more often money. Total more money!
Wrong. 1: Inverted forks while yes have a larger clamp diameter are not torsionally stiffer. Length of Triple Clamp and axle interface determines this. This doesn't take into account internal bushing sliders and their play. However, 99.9% of people will never know. 2: Inverted vs Conventional internals are identical. Fox/Marzocchi/KYB have been like this for years. 3: They are also heavier even with the increase in diameter of the 'female' part and reduction of wall thickness. 4: Higher center of gravity = more inherently unstable. + or - depending on viewpoint. Actual Pros of inverted: ******Better small bump compliance due to reduced un-sprung weight. Most road riders will never know the difference. Off-road is where it takes precedent. ***Oil seals are immersed in oil entirely vs having them be 'splashed' like a conventional thus making them more plush from less stiction.
it's taken from the mid 1960's, when upside down forks first appeared on a European production 50cc motorcycle, until the 1990's for them to catch on for bigger bikes.
Stop reading my mind. Just did my 1975 Honda CB550F supersport forks. Had to rebuild them. My first time doing forks. They leaked from the seals and luckily it dripped off the bottom of the fork to the ground instead on the brake disc. Fun stuff.
Liked the video BUT the most important thing is less mass on an inverted fork. That's part of the reason the feel of them is better, less non suspended mass means better control on rebound and overall compresion. So you can still make weight savings on the whole fork with somewhat the same stiffness, which in the end makes them a high end product.
Dear all, Could the USD fork of those FZ-09 be swapped into FZ-07 with minimal modification, plug-and-play perhaps? Would the triple clamp be of the same size? I do understand that, aside from the USD fork unit, the front brake calipper and disc brake of the FZ-09 would have to be used also, is it correct? Thanks in advance 😀🙏
Please do a video about 1.converting bulb type turn signals to LED turn signals, 2.pros and cons of an aftermarket performance exhaust compared to stock exhausts and differences between titanium, stainless steel and carbon fibre exhausts, 3.info about electrical fuses, 4.difference between forged alloy wheels and cast ones...
Topic suggestion: how often to change fluids in a motorcycle based on usage. For example, do I need to change oil if I only ride 1000 mile a season? How often does brake fluid need to be changed? If I have a classic that's really a garage queen do I need to change fluids once a year?
Some high end enduro bikes came with cartridge standard forks for more comfortable high speed and all day riding 20 years ago before the upside down fork took over everything.
Yep spot on. I remember racing suzuki mx bikes in the mid to late 1990s when they tried to run 50mm conventional forks to stop the flex. They were too big and bulky and it never took off USD look better but ultimately they really don't flex as much on track and it was noticed braking hard into corners or landing jumps when you could move you bar a bit but the wheel would stay straight
1. is there any damage done to the bike with clutchless shifting and where? 2. why does tire traction get worse with wear on dry pavement? 3. Can you judge maximum cornering speed at 45 degree degree lean from if you know the tire's speed rating? or how many lateral g's can a tire take from a given speed rating on asphalt?
Please guide on the right time to have an engine overhaul, and what could be the issues related to this for performing an engine overhaul. n how to identify that it is the right time for work.
Broken seal comparison did it for me! I had a broken seal once, riding out of town (conv. forks) and while there was some spillage of fork oil onto the pads, the pads did go soft and I lost a fair amount of the front braking. However the bike was still ridable to get me where I had to go. Upside down seems likely to render that front end useless if you blow a seal.. Someone correct me if I’m wrong.
Question: If the stanchion part was used upside down on a retracting hydraulic suspension, does everything for the comparison made on this video apply in the same way other than the leak?
I saw a video of the normal forks with every part removed and how to service them now I want to know about the upside down forks servicing and how can I get them or of which brand should I use for inverted forks
Have you guys done a video on handlebar ergonomics? I'm buying a new naked bike soon and I'm curious about the options I have as far as handlebars and how they should fit a person.
Does torque figures outshine the power output of a motorcycle, or shall I ask whether to buy a bike based on the torque figures or the brawny power output?
Welp, I learned something today. How about a vid of all the different types of engine cylinder configurations and their benefits to the kinds of bikes they're put in?
Lets start at the beginning. Forks used to have the skinny section at the bottom, then fashion changed around the 1970s and we got the USD, that is the slider moved to the bottom of the fork. Now we have gone a full 180 and the skinny section is once again at the bottom. So just what should we be calling USD and RWU?
What about sprung weight? The weight of the tire, wheel, brakes and suspension components that move in reaction to the surface of the road. The more weight, the more force you have to overcome when it's moving (bouncing). How does that compare between the two designs. IMHO it seems the conventional fork (with its aluminum lowers) would be less sprung weight than the upside-down model, where the sprung weight now includes the heavier part of the fork. Is this overcome by using something like titanium? Would the lesser sprung weight of a conventional fork be advantageous for the non-competition rider (Cool Joe Points aside)?
On the old forks I just rebuilt, the sliders are far lighter than the tubes. This reduces unsprung weight. I see they try to deal with that by lengthening the top part and shortening the tubes when they invert em', but I wonder what the weight difference is even then.
Will it make a difference? Maybe. I didn't know what fork flex was until I bought a Honda VT750. My previous bike also had right side up forks and was fine.
Thanks for the info. You cleared the hype around this term. So I see why some reviewers just harp about upside down fork- they want to just sound more geeky! 😁
Finally someone explained it in plain language. Thank you!
So like in other things that involve riding, it's better when the female is on top.
lol
tacamo21 Hahaha. Nailed it! (no pun intended)
I came here for this ^ :D
Ari Henning love your videos mate and your name being similar to Arai HAAH
Yeah, it improves the "stiffness" during the ride.
sounds legit. i'm going to turn mine upsidedown
That's so badass !
ϛ/5
@Joziah Remington You liar. Its a scam.
@Joziah Remington well at least you acknowledge nobody gives a shit
Turn the whole bike upside down
Why upside down fork? Because it looks hella cool. Enough said! :D Good video MG!
and even the Brapster have it, so its definitely super cool :)
Yeah!! TheSighBored 😊😊😊
I'm a mechanical engineer in the motorcycle industry, and this is video is 100% exactly right. I have also been racing motocross for over 10 years. Happy to see some media outlets offering actual information about motorcycle engineering to clear up all of the wive's tales.
Glad that you mentioned seal failure. Mine went out in Jacksonville, Florida last March. Bathed both calipers with fork oil - as in puddle on the ground. Made it the 750 or so miles from JAX back home to northern Virginia with NO front brakes. Whee.
Please explain the about the monoshock and the double shock in the rear section.
i was gonna ask that.. but you already did. nevermind i'll ask about single swingarm versus regular swingarm versus curved swingarm.
Monoshock is better for track riding and cornering and can be adjusted for variety of settings.Double shocks are better for offroading and load bearing and are better for bumpy roads as they can take on heavier weights than monoshock.But dual shocks don't lend themselves well for cornering as well as monoshocks do.
Sandepp hahahaha
more pivot points in dual shocks means its geometry is more susceptible to moving in undesired ways. Mono shock makes it rigid by having just one coupling point with the shock.
that makes total sense. any difference in the shock and spring action on either side can cause unwanted twisting forces on the trailing arm.
Nice video. Aircraft shock struts, which are very similar to telescopic motorcycle forks, have always had the outer cylinder on top and the inner piston on the bottom. So, what is right-side-up on an airplane is called upside-down on a motorcycle. BTW, aircraft struts do not have internal springs, but rely on compressed nitrogen gas to bear the weight of the aircraft. Here is what might sound strange: if you see a mechanic adding or releasing nitrogen from a strut, he is changing the extension of the strut, but not the gas pressure in it. The only way to change the pressure is to change the load on the strut.
Well... That really was quite interesting... :)
ummmmm, when i add nitrogen to my Bosbak, i am changing the pressure.
wtf you come up with this theory of yours
Hopelessand Forlorn nice 👏👏👏👏👏
Cool info.
@@faridb40 hilarious. And wrong
wouldn't there also be less unsprung weight with a upside down fork
True, though in _most_ cases (Not all) an inverted fork will have less unsprung mass
In theory, yes. In practice, I'm not so sure... Maybe.
No totally the opposite The stanchion or shinny part is steel and much heavier than the Alloy tube
Blanchy10 What are you smoking? stanchions are light as fuck
Yeah right you ever pull a set apart? The chromed steel part is much heavier
YES THERE IS PERFORMANCE IMPROVEMENT with the inverted fork. It improved my ego. -_-
I swapped the front fork on my TBR7 to an inverted Grom style fork, the difference was notable INSTANTLY!!!!
I got a 43mm conventional right-side forks on my bike and for street riding, touring and occasionally track days it performs quite well, the only upgrade I did with them is installing a good set of quality progressive springs with the right fork oil density and a fully adjustable rear monoshock, a suspension specialist did the job on my bike beautifully and it performs really well.
Additionally, USD-Forks tend to have less unsprung masses than similar sized conventional forks. This may help increase riding comfort and may provide better front tire traction, especially on bumpy roads or on the track, if set up properly.
Keep up the good work,
Greetings from Bavaria!
I think it's rotational mass that actually has the greatest benefit... upside-down forks are better than normal but you will feel lighter brakes, lighter rims far more than if you swapped upside-down forks for conventional... since the suspension itself it technically un-sprung, the weight of the components is what matters, not it's orientation... and the upside-down forks may or may not carry an additional benefit in that category due to the perception of upside-down forks feeling stiffer which may also lead to the perception of lightness since there is less flex overall.
Which suspension setup is better for off road bikes? If we are doing more of off roading?
Telescopic is better for off-road
Conventional right side up is better. Number 1 reason is the fork seals last for years. 2nd they flex more for a plusher ride.
Conventional...usd forks are more for streets and tracks...why? Forkseals.
Conventional forks are more suited for off-road riding because the fork stanchions get battered more with rocks/pebbles,
causing more abrasion of the fork seals by the increased roughness.
And gaiters down low would collect water through their breather holes from streams and puddles.
Bulu bhaina jay Jagannatha! Upside down forks kebala track use pai better. High end motorcycle gudika jouthire conventional forks rahuchi seguda madhya bhari stiff eka. Especially offroading re oil seal herika crack karibara besi chance rahiba hard core offroading karile tenukari conventional setup thik rahiba. Janichi apanakara 3barsa tala comment hele dekhili ta bhabili reply kari diye. 😁 Khusi lagila apana madhya emiti videos dekhuchanti. Have a nice day sir take care❤️
The difference in unsprung mass is minimal in the real context. USD forks are fashionable because they can look like what are on racing bikes. In street riding, the real world, there are cheap, flexy USDs and very good traditional forks that are stiffer. Two problems with USDs: the slider is exposed lower, more prone to chipping and damage, and when the seals fail, they dump out oil on the brakes, and when it comes time to fix all that, they are more complex. Companies are making cheapo USDs anodized gold , i.e. Fauxlins, they are crap. looking at you, Yamaha.
It's a fashion choice, like petal rotors.
It would make sense to put neoprene boots on USD fork sliders, but that's currently not cool.
It’s cool to me. I have an SV650, conventional forks, and I’m not swapping them. But I would like to know what sleeve you’d recommend to cover where the dirt is able to get in. Thank you
My brother built a model for a Revell model contest in 1976, based on Revell's Roger DeCoster Suzuki MX model... He couldn't leave well enough alone, though and proceeded to design a bike that did things that nobody was doing in 1976... including inverted forks.
Finished it a month before the deadline, because we were going to be in Spain when the entry was due.
Wild details:
Working suspension (F & R)
Inverted gas fork design (10+ years before this design showed up in production)
Laid-down rear shock absorbers
Underseat gas tank (lower CG)
Liquid cooled (vs air)
Radiator behind mesh number plate
"Snail" exhaust pipe
Airbox between legs, where gas tank usually is
Padded seat
Working rear brake pedal (actuates spring loaded rod to rear wheel)
The funniest part of the story is that, after winning his local region, his model was sent to the national competition, where 1st prize winner would receive a custom Datsun Li'l Hustler pickup with a then-new Suzuki RM125 in the bed...
1st prize went to a VERY faithfully built and beautifully detailed (mud splatters, etc.) rendition of the DeCoster 400, and 2nd to my brother.
2nd prize was a helmet.
See photo of 1976 model:
uploads.disquscdn.com/images/5b396f42e1fc200370a51ebf2d06e3aeb1fcc7221ab6865e550ee5522c874f6a.jpg
Would the chrome slider be more subject to damage, ie: stone chips etc, being closer to the ground. AUS
Good point. Have you noticed nearly all of them have guards for just that
Yes. That's why there are fork gaiters - to protect the stanchion from rust from road salt and from chips/dents from rocks that cause abrasion of the rubber seal.
Gaiters look Old School and nerdy, but they provide a definite protection for the bike.
That’s why God invented boots.
Nice explanation.. Unless you're pushing the bike ( street or in the woods/dirt trails ) It seems to me to be almost a 50/50 deal for the average rider. A big factor you pointed out is the potential for the seals to leak on the brake components. That's worthy of consideration...
The upside down one gets more dust in the shining part which makes the seal fail quicker
The shiny part is called the stanchion. Boy.
@@bignoseharry6561 good to know info.
It's really easy to make covers for them..
Fork guards remove a large part of that issue. Motocross/enduro all run upside down forks and it works really well. Add a proper wrap-around fork guard if you are doing some more extreme stuff and you'll be set. A positive on the upside down one is that the scraper pushes the dirt down and it stays there, while a conventional fork is more likely to have dirt buildup on the scraper.
I know it's not a totally fair comparison, but my 1980's conventional fork on a road-going machine tends to be more gunked up than my 00's and 10's offroad machines. (including pure motocross and dual sport)
@@Simon-eh5ez upside down isn't always better look at the late 90s rm's. those things have amazing Force way better than the upside down forks on the other dirt bikes at the time.
Love the video's from MC Garage.Clear and easy to understand explanation about how bikes and their components work.
Greetings from the Netherlands,Theo.
You didn't cover the single biggest reason why inverted is better, and it's the same reason why most vehicle hood and trunk lift supports are mounted so that they "rest" in the inverted position. It causes all the shock oil to collect against the seal(s), keeping them wet and lubricated. This prolongs the life of those seals, meaning fewer failures and less maintenance.
That's the very last point he mentioned. Not exactly in your words, but can be easily inferred.
I had Suzuki GT250 engineered by the lads at college in 1977... Aside from engine and carb mods with some reed valves made and fitted, they machined the alloy legs, made triple trees to fit, and fitted twin disc mounts that they'd made...
It revved to 10,500 instead of about 7,000 and seldom needed the very long 6th gear.
The forks didn't leak at all... Just the usual slight sheen as seen on normal configuration...
I finished it in matt black and white lettering and graphics.
I loved that bike...
The USD fork will also typically have less unsprung weight which helps reduce force on the suspension components again improving handling
he stated the in the vid it doesnt make any difference to handling. are there tangible metrics to suggest otherwise? interested to know
mrvwbug44 You mean USDs have more unsprung mass, as the fork tubes are heavier than the slider which is usually made of aluminum. On the other hand some people say that USDs benefit from that lower CoG.
But as Ari suggested, this weight difference has a minor effect, compared to stiffness difference.
To mrvwbug44. Are you sure? That steel pipe is quite heavy compared to the slider. Just a thought. :-)
Sprung weight is only affected once the weight drops lower than the centre of the wheels. Aka lower frame rails, crankcase, transmission etc... As far as the forks are concerned is 100% sprung weight
+Moggy1000 anything that is moving along with the wheel is unsprung load. its not about the position of it.
if you put a sack of potatoes on the front mudguard, the front wheel will have a really hard time to follow the road bumps, which makes handling worse. if you put that same sack of potatoes below the center of the wheel, it will have the same effect. it will still be an unsprung mass.
Very good explained. I am an average sporty driver and own some (classic) motocycles, some with upright forks, same with upsid-down forks. I never felt the difference between them ... best regards from Germany.
as far as I know upside down Forks were introduced for dirt bikes, since you can make longer damping ways with a smaller Fork and for a second reason very big normal forks have tube extending below the axle wich results in them grabbing dirt earlier when driving through deep ruts
Peter Griffin the existed a long time before that - have a look at the BSA Bantam forks from the 1950's....
I was gonna say, talk to dirtbike racers and find out what inverted forks are really about!
Peter Griffin strange that trails bikes have reverted back to conventional I guess they help pop you up over obstacles easier then usd? No idea why just what I’ve noticed
Greetings Mr. Henning all kidding aside and as always I do enjoy your clips. 100% accurate information, yet this clip is different. I merely point this out due to the volume of audience.
1. The slider is the chrome slider with the stanchion being the outter anodized capped tube.
stan·chion
/ˈstan(t)SH(ə)n/
noun
noun: stanchion; plural noun: stanchions
an upright bar, post, or frame forming a support or barrier
It's providing support for the slider.
2. You most certainly will feel the difference. Keeping in mind the many bikes with standard forks which will easily due 100mph and inherently some folks will reach that speed and experience the watusi.
next topic: tyre width. What are reasons manufacturer installs wider tyre in bigger bikes? Besides cool look?
for more grip, lol
It may sound weird to you but amount of grip have nothing to do with tyre width. Wide tyres and narrow tyres have same amount of grip. Forces involved in grip and traction are not that simple.
tyre width does not effect friction.its not about grip its about cooling (bigger surface faster cooling) and handling (for smooth counter steering) etc.
Moto 3 bikes only use a 100 or a 90 section rear tyre. Most 125cc bikes have 130s from factory, so why do racing 250s use skinnier tyres?
lighter and more agile. Thicker means more contact surface (so better grip) and more stabality.
I ride a harley that i beat the hell out of and I had someone tell me the other day “i know someone whos selling an inverted front enf for $500! You should buy them!” I thought about it, but after this video, im happy with my regular forks with the heavy duty springs. Totally worth the money than to waste it on inverted forks.
An idea for a next video would be to go through the nuances of different types of swingarms.
Dual spring, Monoshock or single sided swing arm ?
Moggy1000 A little bit of everything I guess. Origin, pros and cons etc.
Nice, Ari. You do good work. I'm pleased that you didn't muddy the question by launching into an "unsprung weight" discussion, which might be useful to Jorge but for me, waaay to much. Thanks.
I always thought it was about unsprung weight being lower on the U/D forks
Thanks Ari. Another clear and informative video. I love what you and MM are doing with these UA-cam vids!
I have a conventional fork on the left and a USD fork on the right side.
Beat that
.... and a tank slapper any time you go over 25 mph.
@@kogasoldier9379 😂😂😂😂
When you need both 👌👌😉
Thats a 69 then ;) Beat that!
Always had heard about the upside down forks in bike reviews but didn't knew it's significance. Thanks for making this video. 👍
3:12 What? Gravity ensures oil will run down on both fork types. Regardless of distance traveled, oil is just as likely to contaminate the brakes on both types of forks. You've totally missed the point in this issue; the conventional design has the inherent problem where water will find its way into the seal (again through gravity) and cause corrosion in the seal's steel support ring vulcanised inside the rubber. This in turn leads to more frequent leaks and replacement costs for the conventional forks. Every single bike restoration I've done on bikes with conventional forks has required replacement of leaking/corroded seals due to water ingress. This is a major advantage of the difference in design and the way you described the oil issue is irrelevant.
techo61 Nice to see that I'm not the only one who knows that! That is a huge reason to have inverted forks!
Moving masses are smaller on an usd-fork. That makes the wheel a bit faster following the bumpy surface of the road. But that's also a thing you may only notice on racetracks :)
I'd love an explanation on how assist and slipper clutches work!
Thanks for the sweet, simple and on point explanation. Any next smartass who's gonna keep arguing to me that upright fork vs inverted stanchion forks has no difference, I'll slap em with this video.
+Ari Henning you missed mentioning the unsprung weight factor. But I guess it's effective, as you said, only at the limits on a track. I haven't really been able to differentiate USD vs RSU on road conditions. Anyway, good video as always.
A lot of other channels should know that making such short, precise videos is how info videos should be. Not some 15 min long ramble before getting to the point.
Take a bow Motorcyclist Magazine.
I agree with unsprung weight. The thicker part of the fork must weigh more.
" Not some 15 min long ramble before getting to the point " I agree !
I don't comment on UA-cam video's ofren, but I am really impressed with the way Ari covers the quick differences that are indisputable facts. He is so clearly un-biased and just down to share what can be covered without over-complicating the situation with irrelevant hyper performance squabbles.
My favorite bike is an Honda MC22, it comes with conventional forks, they bend often after a crash and are very quick and easy to work on. I could change them to upside down forks but choose not to because in terms of performance the bikes that have upside-down forks in its class e.g. ZX2R don't merit mention due to that fact alone as its probably about 0.00005% of the whole pie in terms of why this guys faster than that guy.
One thing that could have been touched on is that not only are conventional forks much easier to work on but they are much cheaper to replace and the only common time conventional forks bend is after a crash which upside-down forks are still very much susceptible to taking damage from.
In short if you are not a contender in the TT or the GP/Superbikes/Supersports the direction your forks face in terms of performance is virtually irrelevant.
I once owned a 1982 GSX1100 Katana and the forks would twist when you counter steered at highway speeds, it was the freakiest feeling as you would move the bars and then the wheel would follow 1/2 second later
I think you had some issues with that particular fork then... I've had a GSX 1100 EF since 1988 (basically the same front fork, except for the PDF units instead of traditional anti dive units) - I've never had any (noticeable anyway) flexing of my fork because of this.
The EF does have a stabilizer built into the front fender though; this might reduce the problem quite a bit, of course.
I had experience bending and blowing sealings on both type of forks. But I totally agree with points mentioned here.
Please do a topic of 1 vs 2 vs 3 vs 4 cylinders
Honda Valkyrie uses a flat 6 cylinder motor. And Honda once used a 5 cylinder motor (RC211V) in their MotoGP bikes. Add these to the review suggestion please!
There isn't a versus, they all have different attributes in their engine configuration. who ever said there aren't dumb questions was probably a moron.
cylinders basically is replacement of your foot and foot pedal on bicycle. for example in order to move the bike we need certain amount of force, e.g 1 torque. for 1 cylinder, it's like a bike having only 1 pedal, we must give 1 torque on single leg for single rotation. while on 2 cylinders, it's mean having 2 pedals, the weight distributed each cylinders, if bike need 1 torque to move, then each cylinder only need contribute half torque. on 3 cylinders, each cylinder contribute 1/3 torque. and last 4 cylinders, each cylinders contribute 1/4 torque. now if we reverse, let's say each cylinder on 4 cylinders contribute same amount of torque like on 1 cylinder, then the machine produce 4 times more torque than 1 cylinders. ofc, this is just simple math, we must count the structure of the crankshaft, the diameter of the cylinders, height of cylinder head, and so on. but basically, more cylinders mean more torque, not speed but torque.
noface actually more cylinders provide more hp but not torque, few cylinder do produce more torque with the same displacement engine but with more cylinder. Because the engine with few cylinders have more stroke
@@siontheodorus1501 How come we just can't have an 8-cyl engine that goes to 20k RPM then? It would sound way better than anything else and the size of the pistons can be half that of a 4 cyl so the space can be nearly identical.
ahhh, im so happy you did this one Ari! one things ive been wondering for such a long time. keep the videos coming!
This video changed my life 🙈
Also with an upside-down fork you can more easily measure the range of front suspension utilized by putting a zip tie on the rod and riding the bike. The tie will tell you if you're using the entire suspension by its position. Good for suspension adjustment on track days. Hope this makes sense.
The gray Transformer on your left looks sad....
One other benefit is that the upside down fork has less chrome parts open to the elements to cause premature seal wear in the first place, the conventional fork is open to the full front end's wind, rain, dirt and debris that could pit the chrome coating over time. Definite benefit right there.
Idea for a video: slightly controvertial. Piston arrangement. V-Twin vs Boxer vs Parellel vs inline vs v-Twin (transverse). The question this video will be seek to answer is "how does piston arrangement affect how power is transferred to the road and why some companies have stuck to one arrangement while other take a more product by product approach". This originally occurred to me when the new Africa twin was launch and there was a small fraction of rider who expected it to be V-twin like the original and not parallel.
I'd like to see +Ari Henning explaining something like this too.
Crankshaft configuration and the benefits of each.
360° crankshafts, 180° crankshaft and 270° crankshaft
V-engines, In-line engines and horizontally opposed.
Saif , Dont forget the famous V4 and V5!
Saif a parallel twin in my opinion beats a V-Twin any day much more smooth ER and faster revving. A four cylinder motorcycle twice as good as a 2 cylinder motorcycle but has disadvantage of its width and its weight!!! I really really really hate the. V twins
I had a 650 v-twin it had more torque and fun than my current 750cc inline four.
So am scratching my head, as am not as advanced as the tech gurus here ...
The smaller stanchion parts mean less weight that needs to move up and down with the wheel. That’s the biggest reason for USD forks. You mention why a leaked seal could be worse but the other issue is that the sensitive surface is more exposed. It can get pitted with road debris and damage the seals since they are no longer protected by the bike’s fairings. This is why modern front fenders also partially cover the forks, which means the 2008-2012 Ninja 250 is faking it for a modern-looking front fender even though it has standard forks. ;)
Upside Down forks were conventional years ago so Right-Side Up are actually located upside down.. : )
These videos are always good. Y'all are one of my favorite subscriptions.
Fork this, I'm out.
:)
That's all forks!...
what the Fother forking fork!
fork you all
Fork u fother forking forks! ! !
Fork the Forking Forkers....Why don't you go outside and play hide and go Fork Yourself!...Ah FORKIT... Absu-Forking-lutely or In-Forking-credible...
I love watching your videos…!!!
This guy is judo full of helpful information…. and he explains his points very clearly…!!! AWESOME 😎
It's basically missionary and cowgirl😐️
You need a girlfriend dood
More like missionary vs doggystyle......i dont think i would ever want the front forks ontop of me while going down the road.
@@gammaprysem
Gooooooood analogy😂😂😂👌
Reverse cowgirl that's where its at
nah, that's cowgirl vs mating press
If you are looking for comfort, you can choose the straight shock absorber, which will help you hold the road or take turns more easily. If you are traveling on mountain roads or are very fast and heavy, you can choose the reverse shock absorber. As a result, the shock absorber works with load and impact. Since the front wheel will be very light, shock absorbers are preferred depending on the type of motorcycle.
Upside down forks has lower unsprung weight. But it is very difficult to service.
how can it have less unsprung weight when the moving part is made of heavy gauge steel while on normal forks the moving part is made from light weight alloy
I did the fork seal and bush on my crf250l in 10 minutes out in the countryside with only the honda toolkit and a discarded plastic bottle so yeah, theyre real hard to service
Wrong steal is heavier than aluminium. Take a refresher course. Its all ball bearings these days.
@@bjorn1583 it cant.
Great vid. Bottom line is- for MOST RIDING off track you will never know the difference.. Except that USD forks often have more damping adjustments. Both of my bikes have non-USD forks; one has no damping adjustments (sadly) and the other does. That's all that matters. PS- Yup, when I go to service my forks, IT'S A BREEZE. Try that with your USD's
This video is incorrect, pretty much end to end. The fork stiffness isn't the reason that USD forks are now preferred, nether is unsprung or sprung mass (both of which go up with USD forks) its because of fork bush loads.
RWU forks simply used a larger diameter inner tube to improve stiffness, so the last performance bikes to use RWU forks used 46mm tubes not the almost universal 43mm that was transitioned to.
RWU forks also only had an outer in the ballpark of 400mm long, from cast aluminium, which means that its substantially lighter than the nearly meter long piece of steel that is the inner tube, and thats before you take into account that the RWU outer also serves dual duty as a caliper mount bracket, whereas on USD there needs to be a complex bracket attached to the foot of the inner tube. So RWU are lighter than an equivalent USD for stiffness.
The damping in the forks can also be exactly the same depending on what the manufacturer offers.
The reason is because the distance between the fork bushes affects the loads that go through the bushes, because the fork carries a bending moment from any brake loads applied. This means that if you double the distance between the fork bushes you halve the friction, which substantially improves the damping performance of the fork under brakes. The whole "Set up and squeeze" technique of braking exists specifically because fork bushes load up and bind suspension, so if you don't gently apply the brakes then you won't have the suspension start travelling to a "settled" position before it gets locked out by loads. By comparison in USD forks the bushes are far less heavily loaded, and as a result you can be far more aggressive with brake onset and you'll also notice far better suspension performance under braking on the bike. This is critically important if you're doing any of your braking while you're tipping in, because the suspension effectively becomes stiffer due to the angle of the bike.
Apart from anything else, USD forks are useful because they reduce the impact of poor brake application, panic braking... bikes end up skidding down the road because people grab un injudicious handful of brakes in an emergency, even when upright, this is why.
Can u explain in detail regarding the point you mentioned about the reduction of friction..?..
@@akshaysinghgirdhar He is not an engineer. I can tell that he also doesn't have much riding experienced compared to me. Im an engineer who has been racing motocross for over 10 years. On my vintage bike (not my main race bike), I rode with the stock conventional forks for one half of a season. I switched the forks out for a set of USD forks, and cornering drastically improved, regardless of braking. The front end was very bendy and vage feeling with the conventional forks. The USD forks made the bike corner just like a modern dirtbike. Even when you werent using the brakes. Braking was only barely effected when I switched to USD forks. The level of front end control now makes the old forks feel like wet noodles. No front wheel control EVER with conventional forks. With USD forks the front end does exactly what i tell it to.
@@sciencemilitia1853 You start by saying the original poster is not an engineer but you are, and the proceed to just post up an opinion without any explanation to back it up other than "I *feel* it's better".
An engineer would mention the different lengths, materials, diameters, the oil itself etc of the forks and how all these things can affect their performance, only after all those factors have been ruled out could you say anything abut the orientation of the forks making them better or worse and not one of those other factors. You're not an engineer.
@@BigUriel The guy in the video already explained it all. Larger diameter tubes have higher bending strenth. That means less flex. When you compose the larger portion of the fork with the larger diameter tube, you get less total deflection (aka flex).
mr.Drew the best explanation i have ever heard sir!
Bud.. You impress with one video after another.. Great work.
Reduction in unsprung mass is also a huge benefit no??
Yea ... i think its the biggest advantage of all
Slatteea Not as big as you'd think. Because the upper part of the fork on either design bears the greatest load, both are designed to be heavier there than on the bottom. A USD fork has heavy sliders and light stanchions, while RSU forks have light sliders and heavy stanchions. Strong up top, light down below.
JETZcorp I never thought about it that way!
Thanks for the clear and concise information. Some of us needed it, clarity is king.
Don't discount un-sprung weight.
It doesn't change when you count the weight of the internals
The only issue you would have with the stress of a right side up fork being inferior to upside down forks is if they were known for buckling under hard braking. I have never had an issue with my forks buckling on any bike I have ever ridden and a few of them I did some pretty hard road racing with. For the average motorcycle rider that loves the road, I seriously doubt this is of concern at all.
"Why Are Inverted Forks So Good?" because that lose more often the oil (and once start lose had to get fixed) so you make more often money. Total more money!
I really enjoy your videos. Mainly because they are short and helpful with many advice.
Wrong.
1: Inverted forks while yes have a larger clamp diameter are not torsionally stiffer. Length of Triple Clamp and axle interface determines this. This doesn't take into account internal bushing sliders and their play. However, 99.9% of people will never know.
2: Inverted vs Conventional internals are identical. Fox/Marzocchi/KYB have been like this for years.
3: They are also heavier even with the increase in diameter of the 'female' part and reduction of wall thickness.
4: Higher center of gravity = more inherently unstable. + or - depending on viewpoint.
Actual Pros of inverted:
******Better small bump compliance due to reduced un-sprung weight. Most road riders will never know the difference. Off-road is where it takes precedent.
***Oil seals are immersed in oil entirely vs having them be 'splashed' like a conventional thus making them more plush from less stiction.
it's taken from the mid 1960's, when upside down forks first appeared on a European production 50cc motorcycle, until the 1990's for them to catch on for bigger bikes.
SOHC vs DOHC. i have always been curious.
Separate camshaft for inlet and exhaust valves
Stop reading my mind. Just did my 1975 Honda CB550F supersport forks. Had to rebuild them. My first time doing forks. They leaked from the seals and luckily it dripped off the bottom of the fork to the ground instead on the brake disc. Fun stuff.
Liked the video BUT the most important thing is less mass on an inverted fork. That's part of the reason the feel of them is better, less non suspended mass means better control on rebound and overall compresion. So you can still make weight savings on the whole fork with somewhat the same stiffness, which in the end makes them a high end product.
Dear all,
Could the USD fork of those FZ-09 be swapped into FZ-07 with minimal modification, plug-and-play perhaps?
Would the triple clamp be of the same size?
I do understand that, aside from the USD fork unit, the front brake calipper and disc brake of the FZ-09 would have to be used also, is it correct?
Thanks in advance 😀🙏
Please do a video about 1.converting bulb type turn signals to LED turn signals, 2.pros and cons of an aftermarket performance exhaust compared to stock exhausts and differences between titanium, stainless steel and carbon fibre exhausts, 3.info about electrical fuses, 4.difference between forged alloy wheels and cast ones...
Nice! Finally, no marketing bs explanation. Thanks mate!
Actual useful info without the usual crap! Appreciated & subscribed!
Topic suggestion: how often to change fluids in a motorcycle based on usage. For example, do I need to change oil if I only ride 1000 mile a season? How often does brake fluid need to be changed? If I have a classic that's really a garage queen do I need to change fluids once a year?
Some high end enduro bikes came with cartridge standard forks for more comfortable high speed and all day riding 20 years ago before the upside down fork took over everything.
Yep spot on. I remember racing suzuki mx bikes in the mid to late 1990s when they tried to run 50mm conventional forks to stop the flex. They were too big and bulky and it never took off
USD look better but ultimately they really don't flex as much on track and it was noticed braking hard into corners or landing jumps when you could move you bar a bit but the wheel would stay straight
1. is there any damage done to the bike with clutchless shifting and where? 2. why does tire traction get worse with wear on dry pavement? 3. Can you judge maximum cornering speed at 45 degree degree lean from if you know the tire's speed rating? or how many lateral g's can a tire take from a given speed rating on asphalt?
cool video now i know upside down is more rigid but complicated to work on and good thing is now i know there are no differences for commuting
Would you guys be able to make a video on what to check for when buying a used bike?
My Grom,I pulled top caps off and lifted the rod out.Winding the nuts down 13mm doe more travel and a firmer ride.Working well,no bottom outs now.
Please guide on the right time to have an engine overhaul, and what could be the issues related to this for performing an engine overhaul. n how to identify that it is the right time for work.
Broken seal comparison did it for me! I had a broken seal once, riding out of town (conv. forks) and while there was some spillage of fork oil onto the pads, the pads did go soft and I lost a fair amount of the front braking. However the bike was still ridable to get me where I had to go. Upside down seems likely to render that front end useless if you blow a seal.. Someone correct me if I’m wrong.
Question: If the stanchion part was used upside down on a retracting hydraulic suspension, does everything for the comparison made on this video apply in the same way other than the leak?
I saw a video of the normal forks with every part removed and how to service them now I want to know about the upside down forks servicing and how can I get them or of which brand should I use for inverted forks
Have you guys done a video on handlebar ergonomics? I'm buying a new naked bike soon and I'm curious about the options I have as far as handlebars and how they should fit a person.
Can you please brief us on tire upsizing based on rim size. Also, recommendations from your side on this topic.
For practical purposes conventional forks keep the inner portion clear or road debris but inverted forks offer covers to block damaging road debris
Exactly what i wanted to know. Thanks a mill for this. You guys are absolutely too good with this. Keep it up.
Does torque figures outshine the power output of a motorcycle, or shall I ask whether to buy a bike based on the torque figures or the brawny power output?
Welp, I learned something today. How about a vid of all the different types of engine cylinder configurations and their benefits to the kinds of bikes they're put in?
Lets start at the beginning. Forks used to have the skinny section at the bottom, then fashion changed around the 1970s and we got the USD, that is the slider moved to the bottom of the fork. Now we have gone a full 180 and the skinny section is once again at the bottom. So just what should we be calling USD and RWU?
Great explanation, thanks. I notice a lot of Harleys have inverted forks? Is that mainly a strength issue?
What about sprung weight? The weight of the tire, wheel, brakes and suspension components that move in reaction to the surface of the road. The more weight, the more force you have to overcome when it's moving (bouncing). How does that compare between the two designs.
IMHO it seems the conventional fork (with its aluminum lowers) would be less sprung weight than the upside-down model, where the sprung weight now includes the heavier part of the fork. Is this overcome by using something like titanium? Would the lesser sprung weight of a conventional fork be advantageous for the non-competition rider (Cool Joe Points aside)?
Does it make a difference when off-roading? Like on scramblers, adventure bikes and motocross?
On the old forks I just rebuilt, the sliders are far lighter than the tubes. This reduces unsprung weight. I see they try to deal with that by lengthening the top part and shortening the tubes when they invert em', but I wonder what the weight difference is even then.
Will it make a difference? Maybe. I didn't know what fork flex was until I bought a Honda VT750. My previous bike also had right side up forks and was fine.
Trials bikes were produced for only a few years with USD forks but went back to the regular setup due to lighter weight and closer turning radius.
Thanks for the info. You cleared the hype around this term.
So I see why some reviewers just harp about upside down fork- they want to just sound more geeky! 😁