Really good video this. As an engineer is always great to see comments backed up by the sound engineering data/calculations behind them. Great work chaps keep up the good work! :)
@hallbrothersrc you run the same 2 hole piston but you add a shim that deflects easily under the piston. It can either cover one or both holes partially for example. This way your compression damping remains practically the same, but rebound damping is harder. Do that test.
I've been doing that on my no prep drag car on the fronts, so they'd extend quicker than they'd compress... I cut shims out of some really thin lexan that covered about 3/4 of the holes on the top side of the pistons. It worked great after some experimenting.
I’d think for off-road or jumps you’d want slower compression damping and faster rebound. Agreed on the drag racing setup, like 90/10 shocks on 1:1 scale cars 😂
I was debating on using a rubber flap that would close one or 2 holes when it extends, and opens fully on compression, my plan was to use it to slow down the decompression of my rear shock in my drag car 😅
It has been very nice to watch everyone involved in this have a civil thoughtful conversation. I also appreciate everyone involved putting in some actual work and sharing the results. Thank you!
Great response to JQ, found your testing approach was fair and objective. Interesting findings on the reduced rebound under heavy breaking, I'll try them too - with tapered pistons. :) Thanks Hall Brothers!
In my opinion this is one of the best video I have seen in the sport of RC racing I was extremely happy to see JQ get involved because the dialect now has opened upon 1,000 % Keep thinking and keep us in the loop 👌👍
We're still working on the shock setup video, just wanted to get this one out sooner rather than later. Sorry if I sound a bit under the weather, I was slightly ill recording this.
Good response!! Keep thinking about JQ’s note, load transfer (weight change) itself can not be reduced with suspension, you can only make it slower or faster… ✌🏼
Very interesting to hear that this has finally been" discovered ". I have run upside-down shocks on crawlers to much success for a while. I was only thinking cg but wow.👍
Fully agree with both ends of the argument, theory isn't everything though, if you found it better than that's right for you. Brilliant age we are in with these kind of videos helping people understand things. brilliant work guys.
( I think you are both right) I was at the MKGP, I watched the top heat of 2wd, ( i stayed to watch alot of the racing ) i don't know all the technical stuff but i do know what i saw, Tommys car stayed alot flatter in the corners, Orlowski's buggy was lifting the inside rear wheel in the tight corners, It was a very noticable difference. Yes i know Orlowski won the meeting but him and Tommy are at different stages of there racing careers and the racing was so so close.Tommy's car on the day was working better round that carpet track for sure,, and he was unlucky in the last qualifying round, i think you are right at the end of the day it comes down to trade off between pros and cons, a perfect setup is impossible to achive, but a good setup can be found in different ways. Keep up the Great vids. 🍻🏁
Love every single video you make and the knowledge you pass on is priceless , thank you! Also on a funny side of things my buddy’s made a drinking game while watching your videos , EVERYTIME you swallow they take a shot, the games called “blackout” because by the end of your videos everyone is blacked out !!😂..cheers
one of the things i can think of is that manufaturer is doing the cars to light most of the time by making the chassie out of aluminium and mill them out for flex and low weight yet drivers put on extra weights in the cars most of the time. do the chassie plate but of stainles and try how that works with the extra weight and absolut as low as it can go as it is the bottom plate.
@@Luke-en2tk the flex is as i see it adjustable if we say mill the chassie to give flex as a aluminiun chassie but the extra weight as a "special carpet" chassie to give maximum low weight
I am fairly new to the hobby so I am still learning and trying to figure out a good set up. On my 6.4 since I got it I have always struggled with steering. Flipping the shocks around in the back made a vast improvement, a big enough improvement that I have the consistency and my deviation is low enough to step out of rookie. I tried it on my 74.2 but I kept busting off the rear shock caps so I had to change it back. Thinking about getting the aluminum shock caps and Flipping them to see if they will say together unlike the plastic. (At the Florida carpet championship I was last place in 17.5 but Jay that was 2 months after starting the hobby)
I think your Unsprung calculation gave you a higher percentage than it actually would be but no way I can show calculations. So even though I think your calculation was a tad bit off it is off in favor of your argument. It’s been 15+ years since did any engineering (2008 grad Murray State University) but believe your argument on its percentage makes sense for sure. Not sure about the overall argument he was trying to make as to how important that aspect is versus others since never studied this sort of equations. Lap times should prove one’s point to a great deal in a properly setup course though.
Very good video with all the explanations, there´s a question about the level of driving ability: Is the car with inverted shocks harder to drive for non-professionals, so for the average Joe driver?
@JQRacingTV 100%, the unsprung mass is a problem, but if the c.g. is a bigger problem then there is more to gain in that area. As you know, setup is a fine balance of positives and negative. I'm geussing they are finding that the unsprung mass is a penalty worth having to get the c.g lower. obviously once the track isn't super flat then the unsprung mass problem outweighs the c.g. problem. just to add the point you made about the car rolling & weight transfer is very viable with the INSPIRE4 as it weight transfer is instant as it's got little roll due to super low c.g. doing things like putting the shocks on the wrong way to gain better c.g. just proves the INSPIRE4 is the future 😉 then the dont get the unsprung mass penalty.
The springs have little weight and not much height change from flipping. I would assume that it isnt significant enough to matter. The calculations are just estimations anyway. So if you want to be super precise Im sure you can calculate the numbers yourself and get closer numbers.
I think it's fair to say if a 10th buggy was designed from scratch just for carpet racing it would look closer to a touring car in design than a buggy especially for 4wd which are a handful on carpet
How about like an air actuated shock activated by a pressure sensor at all 4 wheels measuring the amount of downforce for all of them and counteracting the transfer based on where the load is out of sync at any given time?
congratulations for not saying the usual phallacy that 99% of RC Racers believe in that it's because the car pitches that the load transfers... Load transfer, whether longitudinal or lateral, only depends on acceleration, height of CG, and wheelbase (or track)... Good video.
So if you designed a front motor 2wd buggy would the force be opposite and push the. Nose down allowing rapid acceleration? What about different motor orientation? Does it have an effect on inertia depending which way the rear motor is mounted? Ie pinion Left or pinion right?
You guys still running your shocks upside down by chance? Just wondering if this stuck for you guys or if it ended up being a fad. It all does seem to make sense though, especially for smooth carpet it doesn't seem like the unsprung weight could be a huge deal.
a bit late to the party but i see a problem that the weight of the oil in the shocks is a part of the shock body and i dont see it in the calculation example.
Engineers and multiple proven theories claim a helicopter cannot maintain controlled flight, but because they obviously can (very well), it doesn’t imply they’re all built wrong for it to contradict the science/theories, does it? IOW: I’m completely tracking your entire explanation/“argument(?)”, and appreciate the time, effort, and very comprehensive way this was all demonstrated & explained. Of course a few tiny weights/measures simply cannot be calculated, due in-part to parts size, inability to be inside these tiny cars, as well as sophisticated tooling that would be required to find every center, bias, etc. I think after showing the many other unsprung weight differences being surprisingly more, showed that flipping the shocks really has no effect. But, if it’s true, swap your tire foams and it’s irrelevant. I’ll certainly be following and trying some things myself. One other thing the other guys didn’t seem to clear up, was that you weren’t actually changing fluids, pistons, etc., meaning part of his argument regarding this really has no bearing on what you’re actually doing (imo)…
Simply put, you could argue that unsprung weight while racing on a perfectly smooth carpet track is irrelevant. Apart from the speed bumps through the chicanes and the ripple section before the straight and after the score board double, which is a small percentage and most of the truly fast guys were clearing those anyway, the cars were either up in the air or flat on the ground, so an unsprung mass increase had a tiny affect compared to all the corners on the track, where the upside down shocks had an advantage. If it was a bumpy astro track, this obviously wouldn’t be the case.
I had always understood it as the unsprung weight kept the tire from staying on the ground over bumps. There isn't many bumps on carpet. And sadly the days of rough off road are long gone in most places.
Did you tabulate lap time averages to learn which is actually the fastest setup? You’d want to run a few packs and different days in each configuration to help remove confirmation bias and warm-up bonuses from practice laps, but that’s pretty much cut straight to the conclusion. Nice work explaining roll moments and transfers, traction loading and many other aspects of the car’s physics. Everybody can benefit from understanding these forces when tuning their buggies. Cheers!
I’m not a fan of carpet off-road. I get that its probably easier to manage a track in some regards, and has advantages, but ultimately I think carpet is for on-road. If its not dirt, its not real off-road.
Loved the video, but feeling faster and being faster is two different things. Were there lap times or section times to compare ? That is the end all be all of the comparisons
in the 4wd with the 'JQ piston' upside down -- did you change the direction of the flap? or is that another testing permutation that could be accomplished?
Could the jumping over the jumps have improved because the reversed shock took sprung weight away causing less compression and landing smother? just a thought from a novice.
Keep as much weight below the axles as possible. If you drew a line front to back at the axle nuts... and then added weight below this line. Makes the vehicle more stable.
Yeah, grip is so incredibly high on carpet that anything you can do to lower the CG is helpful. I wonder if JQ has ever driven on carpet? Maybe if he did he'd change his mind a bit. I enjoy both the Hall bros and JQ videos.
He races tc on carpet in the winter. Also raced the reedy invitational in 10th etc. I'm sure he's raced off road on carpet, he's an actual world class driver.
I agree with what JQ said. It feels you have taken what he said in a bit of a skewed way though? I don't feel he said anything you experienced was wrong, but that by turning the shocks upside down, you sacrifice unsprung weight to improve weight transition characteristics, which appear to be messed up by other factors. If you fix the vehicle dynamics first, then you may find that turning the shocks upside down may not give as much benefit. Your surface is awesome. I had to laugh with JQ's clip of the off-roaders on the tarmac course, because that's exactly what I was thinking when I saw your video. With your surface, you have way too much suspension travel. Suspension travel is necessary to deal with inconsistency in the surface across the contact patches. If you don't have that problem, you really don't need much suspension. I feel your suspension is not suited to that track your setup is geared towards being an ATV, where you need something geared toward F1. When you brake, the back lifts. When you accelerate, the front lifts. You have so much back travel on the suspension that you are almost a see-saw in the corners. My thought is that by turning the shocks around, you move high weight from the body and put it on the wheels, in essence a good compromise given the track since its probably going to help keep your tyres on the ground. The body is then lighter and so reacts to the springs faster (like increasing spring rate would do, which JQ advised) allowing the vehicle to "settle" quicker. JQ advised using springs on the back of the shock piston to reduce the back travel. It may be easier to use some silicone tube. (Nitro fuel line?) Something that works for me is to think about it in terms of frequency. Wheel movement occurs at a (relatively) high frequency. The faster you are travelling, the higher the frequency required for the wheel to maintain contact over any irregularity in the surface. Weight transition occurs at low frequency. Springs store energy. The spring rate determines how much force it can manage at a given frequency. Higher frequency and force requires a higher spring rate. Dampeners (shocks) operate in response to frequency + stroke length. Resistance increases when frequency rises at any given stroke length greater than 0. This absorbs energy from the springs, or from the unsprung mass before going into the springs, and transfers it to the vehicle body as shock. Because you can't change the track, you need to accept that there is a set of frequency requirements your suspension needs to deal with. If you want to go faster, your suspension needs to be able to manage that. To deal with higher frequency requirements, reduce suspension travel. If you want to experience this, just try walking at 2 strides per second. The longer your stride, the harder it is. This is the same with suspension movement. Personally, I would go more severe... I would take the shocks and springs off (don't go over the jumps if you are worried about car damage) and replace them with turn-buckles, or if you don't mind looking agricultural, use my favourite... popsicle sticks. Popsicle sticks can be stacked if you need more strength, but if you start with 1, you should damage the popsicle stick before the car. Why? Your issues relate to movement of the suspension and car body. Eliminate the suspension movement and you can then get a feel for how the body reacts. You could even have the shocks on while having the suspension locked to determine if any centre of gravity related changes are in fact significant, or whether its just allowing the spring to act faster on the body during weight transition. Dampeners [should] be ineffective within the frequency range of weight transition, so you might as well eliminate them as a variable to begin with, since controlling unsprung mass on that surface... If it were me, I would try taping fishing sinkers to the control arms... that would be interesting. It would definitely tell you whether unsprung mass is a consideration. Of course this is theory, and I am reminded of a saying; "In theory there is no difference between theory and practice. In practice, there is." I don't expect the theory to play out perfectly, however this is the process I would use to define a test baseline. That way you have some information to work with regarding the relationship between a fixed suspension geometry and how it feels on different parts of the track. For example, at different heights (and variation between front and rear) you might feel better under braking vs acceleration out of corners. That can give you clues to what the "ideal" response from your suspension would look like, or where to best compromise. Since you appear to have plastic suspension arms, there may be enough give in them (and the tyres) to deal with what is an almost perfect surface. Using turn-buckles or popsicle sticks will allow you to quickly modify your ride height to find what feels best, or at least at what point is the best compromise between handling and height, since you could probably do with at least some travel to take care of those jumps... If you don't mind the potential reduction in lifespan of your suspension components (arms, knuckles, hubs, bearings and perhaps wheels) it may be that there is enough give in your suspension arms to handle turn-buckles instead of shocks. Otherwise, I would pack behind the piston with silicone tube to get the right static height, then use more on the shaft as a bump stop since you say you can't do much about spring rate. If you have only a few mm of travel, you may not need the spring, in which case you make sure the silicone meets the shock and acts as the spring. Whether you keep the shock inverted or not... you can test that again at the end, and to be honest, if its faster that way, keep it. With minimal stroke, you may want to start with no holes in the dampener piston, or 1 very small one if the tolerances are good and you can't get enough oil around the piston. As stroke length increases, so should oil flow rate through the piston.
This subject and both approaches are extremely interesting. It has me asking the question would the inverted shocks combined with some of jqs suggestions be potentially even better?
Sounds as if you missed adding the weight of the oil that is now moving up and down as unsprung weight. It does not move in the standard position. Maybe I missed it but I don't think so. Not that I am arguing against the benefit but making sure the thought and calculation process is accurate. This also affects the calculations on the lower cg as well and must be added in again.
I believe you can get rid of most of the load transfer by using tuned mass damper. Not sure if they exist in rc but they use them in formula cars. Someone else might know more but that could be an option.
@@Dav5049915 completely wrong slicks with additive and warmers would be way quicker especially for 4wd, used to run buggies on foam tyres. They would also last a lot longer
It’s a tuning option for carpet only, I doubt the hall brother will use upside down shocks anywhere outside on Astro or dirt tracks as there is multitude of small bumps on those sorts of tracks.
The 4wd's looked way too fast and not hugely fun to drive, they should have definitely ran them before the 2wd's. We have the same issue with mod TC at the moment, some clubs are now experimenting with running 5t blinky instead of open mod which has large declining numbers all around the world
TC feels like it start to get way out of hand, just a kit is double the money of a buggy and to that comes titanium stuff and other parts so a TC cost in the end 2-3 times of a race ready buggy.
so you just gonna ignore the psyhics behind this called rotational forces just because you dont understand them and then make a 1hour vid about how you dont know how to solve this, good job kiddo get back to school
Actually rc shocks are all inverted in reference to all types of shockers in the world on cars motorbikes they all run this way as standard it's only rc that mounts them as standard the other way round
Can’t you guys just go out drinking together and just fight and make friends again like how it should be? Man you got a response video to a response video! What’s next? A response video to a response video to a response video? No! Just get drunk together argue it out and fight then make up then race each other
Really good video this. As an engineer is always great to see comments backed up by the sound engineering data/calculations behind them. Great work chaps keep up the good work! :)
@hallbrothersrc you run the same 2 hole piston but you add a shim that deflects easily under the piston. It can either cover one or both holes partially for example. This way your compression damping remains practically the same, but rebound damping is harder. Do that test.
I've been doing that on my no prep drag car on the fronts, so they'd extend quicker than they'd compress... I cut shims out of some really thin lexan that covered about 3/4 of the holes on the top side of the pistons. It worked great after some experimenting.
I’d think for off-road or jumps you’d want slower compression damping and faster rebound.
Agreed on the drag racing setup, like 90/10 shocks on 1:1 scale cars 😂
I was debating on using a rubber flap that would close one or 2 holes when it extends, and opens fully on compression, my plan was to use it to slow down the decompression of my rear shock in my drag car 😅
It has been very nice to watch everyone involved in this have a civil thoughtful conversation. I also appreciate everyone involved putting in some actual work and sharing the results. Thank you!
Great response to JQ, found your testing approach was fair and objective. Interesting findings on the reduced rebound under heavy breaking, I'll try them too - with tapered pistons. :) Thanks Hall Brothers!
In my opinion this is one of the best video I have seen in the sport of RC racing
I was extremely happy to see JQ get involved because the dialect now has opened upon 1,000 %
Keep thinking and keep us in the loop 👌👍
We're still working on the shock setup video, just wanted to get this one out sooner rather than later. Sorry if I sound a bit under the weather, I was slightly ill recording this.
Took your recommendation on the short chassis for the B6.4 and have been loving it. Keep up the good videos!
Good response!! Keep thinking about JQ’s note, load transfer (weight change) itself can not be reduced with suspension, you can only make it slower or faster… ✌🏼
Very interesting to hear that this has finally been" discovered ".
I have run upside-down shocks on crawlers to much success for a while. I was only thinking cg but wow.👍
Fully agree with both ends of the argument, theory isn't everything though, if you found it better than that's right for you. Brilliant age we are in with these kind of videos helping people understand things. brilliant work guys.
( I think you are both right) I was at the MKGP, I watched the top heat of 2wd, ( i stayed to watch alot of the racing ) i don't know all the technical stuff but i do know what i saw, Tommys car stayed alot flatter in the corners, Orlowski's buggy was lifting the inside rear wheel in the tight corners, It was a very noticable difference. Yes i know Orlowski won the meeting but him and Tommy are at different stages of there racing careers and the racing was so so close.Tommy's car on the day was working better round that carpet track for sure,, and he was unlucky in the last qualifying round, i think you are right at the end of the day it comes down to trade off between pros and cons, a perfect setup is impossible to achive, but a good setup can be found in different ways. Keep up the Great vids. 🍻🏁
Dang, you kids are smucking fart! Great content, articulation, and presentation. You boys get the serious high 5. Thanks for posting. Cheers!
Thanks for getting so deep into this. I race on clay and I’m curious if you could do a clay setup video.
Love every single video you make and the knowledge you pass on is priceless , thank you! Also on a funny side of things my buddy’s made a drinking game while watching your videos , EVERYTIME you swallow they take a shot, the games called “blackout” because by the end of your videos everyone is blacked out !!😂..cheers
one of the things i can think of is that manufaturer is doing the cars to light most of the time by making the chassie out of aluminium and mill them out for flex and low weight yet drivers put on extra weights in the cars most of the time.
do the chassie plate but of stainles and try how that works with the extra weight and absolut as low as it can go as it is the bottom plate.
I don't think it would have enough chassis flex. It's always better to have a light car then the weight can be placed where you want it
@@Luke-en2tk the flex is as i see it adjustable if we say mill the chassie to give flex as a aluminiun chassie but the extra weight as a "special carpet" chassie to give maximum low weight
Great analysis. Quality content here. Thank you
I am fairly new to the hobby so I am still learning and trying to figure out a good set up. On my 6.4 since I got it I have always struggled with steering. Flipping the shocks around in the back made a vast improvement, a big enough improvement that I have the consistency and my deviation is low enough to step out of rookie. I tried it on my 74.2 but I kept busting off the rear shock caps so I had to change it back. Thinking about getting the aluminum shock caps and Flipping them to see if they will say together unlike the plastic. (At the Florida carpet championship I was last place in 17.5 but Jay that was 2 months after starting the hobby)
I think your Unsprung calculation gave you a higher percentage than it actually would be but no way I can show calculations. So even though I think your calculation was a tad bit off it is off in favor of your argument. It’s been 15+ years since did any engineering (2008 grad Murray State University) but believe your argument on its percentage makes sense for sure. Not sure about the overall argument he was trying to make as to how important that aspect is versus others since never studied this sort of equations. Lap times should prove one’s point to a great deal in a properly setup course though.
Is there a link to the pistons used or piston flap to purchase them?
Very good video with all the explanations, there´s a question about the level of driving ability:
Is the car with inverted shocks harder to drive for non-professionals, so for the average Joe driver?
How did you make the valves in the xray shocks
Oh and great series of videos, keep up the good work 👍
i agree both with JQ and Jamie. JQ looking at it for a ture offroad setup where as Jamie is coming at it from a very smooth flat carpet track.
If that was true F1 cars would not be bothered about unsprung weight…,,
@JQRacingTV 100%, the unsprung mass is a problem, but if the c.g. is a bigger problem then there is more to gain in that area. As you know, setup is a fine balance of positives and negative. I'm geussing they are finding that the unsprung mass is a penalty worth having to get the c.g lower. obviously once the track isn't super flat then the unsprung mass problem outweighs the c.g. problem.
just to add the point you made about the car rolling & weight transfer is very viable with the INSPIRE4 as it weight transfer is instant as it's got little roll due to super low c.g.
doing things like putting the shocks on the wrong way to gain better c.g. just proves the INSPIRE4 is the future 😉 then the dont get the unsprung mass penalty.
Flipping might raise the height of the springs. Was this factored in? Thanks.
The springs have little weight and not much height change from flipping. I would assume that it isnt significant enough to matter. The calculations are just estimations anyway. So if you want to be super precise Im sure you can calculate the numbers yourself and get closer numbers.
Would you recomend inverted shocks on some thing more bumby like asto if you think about how small difference in unsprung weight? Nice vid keep it up
I think it's fair to say if a 10th buggy was designed from scratch just for carpet racing it would look closer to a touring car in design than a buggy especially for 4wd which are a handful on carpet
How about like an air actuated shock activated by a pressure sensor at all 4 wheels measuring the amount of downforce for all of them and counteracting the transfer based on where the load is out of sync at any given time?
I'd like to know your thoughts on the Tenth Technology Predator X10 and how it's setup compares to the gen buggies.
congratulations for not saying the usual phallacy that 99% of RC Racers believe in that it's because the car pitches that the load transfers... Load transfer, whether longitudinal or lateral, only depends on acceleration, height of CG, and wheelbase (or track)... Good video.
actually, JQ says the same thing as you at 18:00...
actually you acknowledge this too :D
i know its a old video but im surprised these high traction buggys arent using a cantileversystem.
Interesting stuff. I was just wondering how flipping the shocks would work the other day.
Does the same idea apply to a sealed clay track?
So if you designed a front motor 2wd buggy would the force be opposite and push the. Nose down allowing rapid acceleration? What about different motor orientation? Does it have an effect on inertia depending which way the rear motor is mounted? Ie pinion Left or pinion right?
yes
You guys still running your shocks upside down by chance? Just wondering if this stuck for you guys or if it ended up being a fad. It all does seem to make sense though, especially for smooth carpet it doesn't seem like the unsprung weight could be a huge deal.
Will inverted shocks work on high grip clay?
Lower center of gravity is always a good thing! We’ve been doing it on crawlers for years!
a bit late to the party but i see a problem that the weight of the oil in the shocks is a part of the shock body and i dont see it in the calculation example.
Engineers and multiple proven theories claim a helicopter cannot maintain controlled flight, but because they obviously can (very well), it doesn’t imply they’re all built wrong for it to contradict the science/theories, does it?
IOW: I’m completely tracking your entire explanation/“argument(?)”, and appreciate the time, effort, and very comprehensive way this was all demonstrated & explained. Of course a few tiny weights/measures simply cannot be calculated, due in-part to parts size, inability to be inside these tiny cars, as well as sophisticated tooling that would be required to find every center, bias, etc. I think after showing the many other unsprung weight differences being surprisingly more, showed that flipping the shocks really has no effect. But, if it’s true, swap your tire foams and it’s irrelevant. I’ll certainly be following and trying some things myself. One other thing the other guys didn’t seem to clear up, was that you weren’t actually changing fluids, pistons, etc., meaning part of his argument regarding this really has no bearing on what you’re actually doing (imo)…
Simply put, you could argue that unsprung weight while racing on a perfectly smooth carpet track is irrelevant.
Apart from the speed bumps through the chicanes and the ripple section before the straight and after the score board double, which is a small percentage and most of the truly fast guys were clearing those anyway, the cars were either up in the air or flat on the ground, so an unsprung mass increase had a tiny affect compared to all the corners on the track, where the upside down shocks had an advantage.
If it was a bumpy astro track, this obviously wouldn’t be the case.
maybe inverted is good for on road?
hehe time to test it?
I had always understood it as the unsprung weight kept the tire from staying on the ground over bumps. There isn't many bumps on carpet. And sadly the days of rough off road are long gone in most places.
Did you tabulate lap time averages to learn which is actually the fastest setup? You’d want to run a few packs and different days in each configuration to help remove confirmation bias and warm-up bonuses from practice laps, but that’s pretty much cut straight to the conclusion. Nice work explaining roll moments and transfers, traction loading and many other aspects of the car’s physics. Everybody can benefit from understanding these forces when tuning their buggies. Cheers!
We tried the same with touring cars about 18 years ago.
Are you still using inverted on the rc10b7?
i think its used, seen some B7 at tracks with UsD dampers.
Super thick diff oil is the issue on corner you understeer due to the locked diff run a looser diff and you won't understeer as much
We've tried a wide range of oils between 7-100k and seem to prefer higher.
I’m not a fan of carpet off-road. I get that its probably easier to manage a track in some regards, and has advantages, but ultimately I think carpet is for on-road. If its not dirt, its not real off-road.
Great video fellas 👏
Loved the video, but feeling faster and being faster is two different things. Were there lap times or section times to compare ? That is the end all be all of the comparisons
in the 4wd with the 'JQ piston' upside down -- did you change the direction of the flap? or is that another testing permutation that could be accomplished?
the flap works in correct way eaven with a up and down shock.
Very interesting video, thank you
Could the jumping over the jumps have improved because the reversed shock took sprung weight away causing less compression and landing smother? just a thought from a novice.
I know what your talking bout, because the weight is upside down the total weight compressing is less? Yes or no
Keep as much weight below the axles as possible.
If you drew a line front to back at the axle nuts... and then added weight below this line. Makes the vehicle more stable.
Yeah, grip is so incredibly high on carpet that anything you can do to lower the CG is helpful. I wonder if JQ has ever driven on carpet? Maybe if he did he'd change his mind a bit. I enjoy both the Hall bros and JQ videos.
He races tc on carpet in the winter. Also raced the reedy invitational in 10th etc. I'm sure he's raced off road on carpet, he's an actual world class driver.
I agree with what JQ said. It feels you have taken what he said in a bit of a skewed way though?
I don't feel he said anything you experienced was wrong, but that by turning the shocks upside down, you sacrifice unsprung weight to improve weight transition characteristics, which appear to be messed up by other factors.
If you fix the vehicle dynamics first, then you may find that turning the shocks upside down may not give as much benefit.
Your surface is awesome. I had to laugh with JQ's clip of the off-roaders on the tarmac course, because that's exactly what I was thinking when I saw your video.
With your surface, you have way too much suspension travel. Suspension travel is necessary to deal with inconsistency in the surface across the contact patches. If you don't have that problem, you really don't need much suspension. I feel your suspension is not suited to that track your setup is geared towards being an ATV, where you need something geared toward F1.
When you brake, the back lifts. When you accelerate, the front lifts. You have so much back travel on the suspension that you are almost a see-saw in the corners.
My thought is that by turning the shocks around, you move high weight from the body and put it on the wheels, in essence a good compromise given the track since its probably going to help keep your tyres on the ground. The body is then lighter and so reacts to the springs faster (like increasing spring rate would do, which JQ advised) allowing the vehicle to "settle" quicker.
JQ advised using springs on the back of the shock piston to reduce the back travel. It may be easier to use some silicone tube. (Nitro fuel line?)
Something that works for me is to think about it in terms of frequency.
Wheel movement occurs at a (relatively) high frequency. The faster you are travelling, the higher the frequency required for the wheel to maintain contact over any irregularity in the surface.
Weight transition occurs at low frequency.
Springs store energy. The spring rate determines how much force it can manage at a given frequency. Higher frequency and force requires a higher spring rate.
Dampeners (shocks) operate in response to frequency + stroke length. Resistance increases when frequency rises at any given stroke length greater than 0. This absorbs energy from the springs, or from the unsprung mass before going into the springs, and transfers it to the vehicle body as shock.
Because you can't change the track, you need to accept that there is a set of frequency requirements your suspension needs to deal with. If you want to go faster, your suspension needs to be able to manage that.
To deal with higher frequency requirements, reduce suspension travel. If you want to experience this, just try walking at 2 strides per second. The longer your stride, the harder it is. This is the same with suspension movement.
Personally, I would go more severe...
I would take the shocks and springs off (don't go over the jumps if you are worried about car damage) and replace them with turn-buckles, or if you don't mind looking agricultural, use my favourite... popsicle sticks. Popsicle sticks can be stacked if you need more strength, but if you start with 1, you should damage the popsicle stick before the car.
Why?
Your issues relate to movement of the suspension and car body. Eliminate the suspension movement and you can then get a feel for how the body reacts. You could even have the shocks on while having the suspension locked to determine if any centre of gravity related changes are in fact significant, or whether its just allowing the spring to act faster on the body during weight transition.
Dampeners [should] be ineffective within the frequency range of weight transition, so you might as well eliminate them as a variable to begin with, since controlling unsprung mass on that surface... If it were me, I would try taping fishing sinkers to the control arms... that would be interesting. It would definitely tell you whether unsprung mass is a consideration.
Of course this is theory, and I am reminded of a saying; "In theory there is no difference between theory and practice. In practice, there is." I don't expect the theory to play out perfectly, however this is the process I would use to define a test baseline. That way you have some information to work with regarding the relationship between a fixed suspension geometry and how it feels on different parts of the track. For example, at different heights (and variation between front and rear) you might feel better under braking vs acceleration out of corners. That can give you clues to what the "ideal" response from your suspension would look like, or where to best compromise.
Since you appear to have plastic suspension arms, there may be enough give in them (and the tyres) to deal with what is an almost perfect surface.
Using turn-buckles or popsicle sticks will allow you to quickly modify your ride height to find what feels best, or at least at what point is the best compromise between handling and height, since you could probably do with at least some travel to take care of those jumps...
If you don't mind the potential reduction in lifespan of your suspension components (arms, knuckles, hubs, bearings and perhaps wheels) it may be that there is enough give in your suspension arms to handle turn-buckles instead of shocks.
Otherwise, I would pack behind the piston with silicone tube to get the right static height, then use more on the shaft as a bump stop since you say you can't do much about spring rate. If you have only a few mm of travel, you may not need the spring, in which case you make sure the silicone meets the shock and acts as the spring. Whether you keep the shock inverted or not... you can test that again at the end, and to be honest, if its faster that way, keep it.
With minimal stroke, you may want to start with no holes in the dampener piston, or 1 very small one if the tolerances are good and you can't get enough oil around the piston. As stroke length increases, so should oil flow rate through the piston.
This subject and both approaches are extremely interesting. It has me asking the question would the inverted shocks combined with some of jqs suggestions be potentially even better?
this is covered towards the end of the video
Why didn't you show lap times or video of actual testing?
Sounds as if you missed adding the weight of the oil that is now moving up and down as unsprung weight. It does not move in the standard position. Maybe I missed it but I don't think so. Not that I am arguing against the benefit but making sure the thought and calculation process is accurate. This also affects the calculations on the lower cg as well and must be added in again.
Very interesting. 👍
You also are not taking in consideration of the flex that's going on in the car.
11mins and I think I still understand #youtubegoat
Do you have any 8th scale content?
I believe you can get rid of most of the load transfer by using tuned mass damper. Not sure if they exist in rc but they use them in formula cars. Someone else might know more but that could be an option.
Tommy looks weird without a hat on.
It also makes no sense running spike tyres on carpet, full slicks would be loads faster
Not a chance.
It'd be like having one side of velcro being smooth.
The knobs bite into the carpet
@@Dav5049915 completely wrong slicks with additive and warmers would be way quicker especially for 4wd, used to run buggies on foam tyres. They would also last a lot longer
I tried it on clay for laughs . Didnt like
It’s a tuning option for carpet only, I doubt the hall brother will use upside down shocks anywhere outside on Astro or dirt tracks as there is multitude of small bumps on those sorts of tracks.
The 4wd's looked way too fast and not hugely fun to drive, they should have definitely ran them before the 2wd's. We have the same issue with mod TC at the moment, some clubs are now experimenting with running 5t blinky instead of open mod which has large declining numbers all around the world
TC feels like it start to get way out of hand, just a kit is double the money of a buggy and to that comes titanium stuff and other parts so a TC cost in the end 2-3 times of a race ready buggy.
so you just gonna ignore the psyhics behind this called rotational forces just because you dont understand them and then make a 1hour vid about how you dont know how to solve this, good job kiddo get back to school
Actually rc shocks are all inverted in reference to all types of shockers in the world on cars motorbikes they all run this way as standard it's only rc that mounts them as standard the other way round
its a bit depending on if its like motocross with preassurised shocks or standard as you say just mounted with the fat side down :)
Who else here because of JQ?
Just join mayako already. And race 8th scale
JQ knows his stuff he wrote a book called invisible speed
all those shocks are already "upside down" in their normal position, please learn about google and technology
But they are now upside-down vs how they come standard on RC cars
TEAM ASSOCIATED CUSTOMER SERVICE SUCKS!!!!!! Gl
what about helping the side weight balance with adding +hubs on? widening the car... Does that help?
no def not, having weight on the sides is what makesit unstable on hte corver
@@ohhi5237 sorry i only meant wider hubs to make it more wide and stable.
Shift weight forward. Problem solved
Can’t you guys just go out drinking together and just fight and make friends again like how it should be? Man you got a response video to a response video! What’s next? A response video to a response video to a response video? No! Just get drunk together argue it out and fight then make up then race each other