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This is the best video on this topic on yt. Subscribed.

Thank you for creating videos in such detail and explaining everything! How well you put together every information makes undestanding really easy and followable. Instant subscribe and like. Please keep up creating these absolutely valuable videos in this quality! I always dream about findig videos like this.

Absolutely fantastic video, loving the examples as well, working with numbers and their effects! One thing I would have also mentioned, is that motion ratio is often not a fixed number - on some suspensions, based on the design, it may vary as the spring moves from bump to rebound (or vice versa), and may change in non-insignificant amounts.

I think body roll is more important then jacking, because big car manufacturers make different hubs (witch costs a lot of $) for the same car with lover suspension option, to bring back up roll center. If lowering roll center (and jacking force) wouldn't make suspension perform much worse, they wouldn't go out of their way to change it.

I'm a idiot but i found out about this and it became a core issue in the MR2 Community because of one guy who revolutionized it for competitive practices, leading to a lot of very competitive MR2s in the 2010s that also were sweethearts, joyful, amazing to drive when the standard (SW20 mainly) has serious flaws. My shortest take is its a naming issue, if this was just "Camber Change" and "Camber Change Multiplier" everyone would understand it. There IS a lot more going on obviously, as going too low sounds like a easy solution from a vehicle driving dynamics if not a max potential dynamics (i mean for the rear generally, on rwd cars), but at its core the subject is one where a weird engineering name alienates what otherwise should be a simple enough concept to grasp.

Thank you for this video. This is the set up for my 76 Ventura and it was a big help for me while I replaced my broken leaf springs

Fantastic instruction! Only one addition or maybe an addendum would be how the curve changes when towing a gooseneck/5th-wheel trailer, a bumper pull trailer, etc..

This guy's channel is missing a few zeros in the subscriber count. What a clear, concise, direct and understand explanation of all things suspension. How wonderful is a world where everyone can access this guy's wisdom?

Question I have is do these geometry behaviors come into play during steady state dynamics (not actively accelerating or braking)? I see alot of design with a very high emphasis (85%+) around Anti's and not sure they should be that high in design criteria.

There is another reason for the front/rear shock offset on solid axle leaf sprung vehicles. When the suspension is exposed to any common mode bump (that is when both wheels see the same deflective force at the same time, like going over a speed bump), the leaf springs are also deformed about a point who's dynamic center of rotation is the attachment point for the shock. The shock of course tries to resist any instantaneous movement. If both shocks are located on the same side of the axle then the leaf spring is allowed to distort thus rotating the axle. When the shocks are split, one on the front and one on the rear, then this common mode bump deflection and resultant tendency to axle deflection is resisted.

Cool

Awesome, more please, training to be an alignment instructor

This is gold! Thank you so much!

When using the instantaneous radius method, you talk about locking the brake to lock the wheel to the upright. Does this mean that the contact patch location on the tire is the same point used at zero deflection, rotated with the knuckle (if the knuckle rotates) for the up/down deflected positions? Or do you still just drop a line straight down from the axle centerline for the deflected positions? I'm trying to analyze the multi-link rear suspension on my BRZ, which has a lot of angle in the trailing link, and may cause some rotation of the knuckle when deflected, making a significant difference in the front/back location of the contact patch between the two methods.

Can anti-squat help with traction on front wheel drive cars?

Does this apply if I accelerate and decelerate the car when driving in reverse? 😮

Is this the way it works on bikes too?

I guess the wheel and its associated components would be considered sprung mass in relation to the tire tread's "unsprung mass" on the pavement. I speculate this is why a good tire at certain inflation pressures can have a major impact on ride quality for high frequency bumps. The tread on the pavement may be only 0.3 kg and the rest of the wheel dynamic components may be 30 kg giving a 100:1 sprung to unsprung ratio for the modeling of the wheel components. It would be interesting to see what impact this has on overall comfort and performance and what are good ratios for this subsection of the suspension?

I love these videos! Such enlightening info, so incredibly to the point. Your videos have a magical property... when I listen to you talk about suspension I actually visualise my years of accumulated useless fake information separating from the good information, like a shaken up lava lamp re-forming its layers ❤

6:40 this seems to be an arbitrary limitation. As a reasonably good structural engineer can design the frame-rail around the ideal shock location. There is nothing that prevents the frame rails from being farther outboard than this, with a significant bend, looping inward around the shock. Or even a narrowing of the rail section in this area, with a specialized shock mount designed to carry some of the frame loads across this frame rail weak point. Also, I think from how I understand this; the outboard shock can be angled to a more outboard mounting position at the axle, with the top canted inboard. If this angle was correct, the shock would provide maximum damping ratio at maximum body roll. While reducing damping ratio in the vertical by the sin of the angle. Although, this effect is probably small, perhaps 5%. It could be a meaningful improvement. Especially if the lower mounting point was located inside the wheel rim, very near the axle flange/hub. (Assuming this wont interfere with the brakes, which it probably will).

I would be interested in a video on leaf-spring suspension geometry. As I understand it, depending in the longitudinal angle and cant-angle of the springs, this can lead to some interesting advantages or undesirable outcomes. I believe based on limited information available NASCAR teams are able to obtain rear-wheel steering under cornering to improve stability.

4:30 an excellent visual for this jacking effect, is Robbie Gordons Stadium Super Truck race series.

These videos are invaluable. Thank You. Around 6-7 years ago, I could have really benefited from these specific videos. Bookmarked, in case I ever revisit this subject.

Great videos. After watching a few i subed. Perhaps you could cover some live axle suspension with regards to towing. Load distribution ect.

A bias towards rear wheel braking is how they set up cars in your favorite car chase movie, non CGI. Example Bullet. You will see the rear wheels lock up when the front wheels continue to turn. The front wheels continue to turn so the driver can maintain vehicle control in those stunt driving shots. As cool as it looks in the movies, not something you want on your daily driver.

The attack on your audio compressor is too high. Reduce the amount to a normal speaking voice level. Other than that excellent info. Id like to see more about live axle suspension. Perhaps front live axel.

Nothing better than listening to someone who has a true understanding of a certain subject.

Thank you! Learned a great deal.

How exactly is the center of gravity height defined, e.g. when the vehicle would stand on an axle articulation test with FL and RR wheels up and FR and RL wheels down? Does it have to be defined per wheel? Also, what would happen with a rear wheel driven independent suspension with regards to anti-squat / anti-lift? How does the suspension "know" where the weight transfer is coming from? (since this will change whether one draws the line from the contact patch or the wheel hub if I understand correctly)

Hello again, after some thinking about this concepts, another doubt arose in my mind... how does anti angles affect spring rates? I mean, if the load is counteracted from the suspension components, does this mean less load is left for the springs? If yes is it as straight forward as if I have 50% anti angle, half of the load is reacted by the suspension components and the other half by the springs? Does this apply also with the vehicle at rest so does it affect spring choice and thus ride frequency in any way? Or am I wrong with this thoughts? I'm sorry I'm asking these many question, and I really hope you'll find some time to explain. Thanks again

This is BS. Just because you may eliminate squat, DOES NOT mean weight transfer is eliminated.

Excellent video. Thanks for making it. I came across this channel while trying to tune understeer out of my car. I have a Mercedes c43 that understeered like a dog from factory whereas my driving style is oversteer biased. I first tried camber bushings, but they deflected too much under acceleration and braking. I didn't want these snapping on me at the racetrack so I thought maybe getting height adjustable springs and dialing in some 'rake' might help. In practice, it really did and I was able to 5s faster on a 2m lap at my local racetrack. But seems like in theory it should've created understeer? I feel the motions that you describe using the model car - pitch + roll instead of just roll with the added rake but somehow it seems to oversteer instead of understeer. Any theories why? Also, what would be the recommended way to dial in oversteer? I've already tried playing with the tire pressures.

Kind Sir!, I still have trouble wrapping my head around moment 8:57. If the driving torque is applied from the engine through differential, then finally to the wheels, why did you say that in case of independent suspension differential outputs opossing toruqe regarding the wheels? Isn't the differential the very thing carrying torque from an engine to wheels? If you could come up with some other explanation of that I would be very thankful.

Bump Steer on both of my cars are excessive

I would love to hear your thoughts on the Citroen DS suspension.

I bought this car on 2016 because its confort, but let me tell ya after 300k losts of repairs need to be made, f.e. silent blocks, water hoses, rods rubbers rotten, etc..

Thank you so much, really appreciate how you explain details like front-rear torque split. I'm curious though, this method of finding anti-squat implies that the antisquat is unaffected by how far forwards or backwards the CG is, is that correct? Other methods I've seen would have the "ideal slot angle" also be a function of the CG's longitudinal position, not just its height

Or go fwd.

Does adding weight underneath the car by increasing its lower center of gravity, therefore decrease body roll?

Wow. EXCELLENT content. Very informative. Thank you!

He said "hello" and I said "and welcome, in this vid..." White boards be doing things to me...

Jaguar cars have the best integral link systems

Thanks for your very well explained video. I am studying currently a suspension design (double wishbone) and this helps a lot understanding the plots a got for many parameters around the roll center.

Hi. Very nice video! I see that you used in your illustrations fixed calipers for the front and floating calipers for the rear brakes. Why are the fixed calipers better than the floating ones? I see them only in high end cars.

Hello and thanks for this tech videos, they are really helpful to fully understand and put all together the pieces you find here and there. I've got a question for you: how do you decide/know how much anti squat is needed? Thank you again!

Thanks for the video, I am learning so much! Quick question, I currently am lowered with coilovers. Do you think adjusting the coilovers back to stock ride height would have a more positive impact on the cars performance?

The more I view your videos, the greater my understanding of suspensions get. Thank you for lighting some light up on issues that we previously had on our race car.

I have an E90 BMW, it's interesting that the M Sport version has approx 10mm lower ride height than standard, and they sell a "rough road" version that is 10mm higher. All the suspension components are the same, except the springs and an optional spacer above the strut. Would be interesting to see which configuration BMW optimised. The M3 version has a slightly longer control arm in the front to give it increased camber.

What is your opinion on using a suspension like this . (4link with watts link) use heim joints on all positions. Except where they mount to the frame, in those positions use joints use either rubber or polyurethane bushings . Do you think this would give a decent ride. Every thing I know I learned from studying and some work on lowered trucks and race cars. Part of my study was a degree I earned from trucking magazine. Haha.. I had to build my own parts . I had a two link and kept one leaf spring to locate the diff. Far from perfect but it worked.. had air suspension. I really wanted a 4link with watts link. The tire size and rim width didn't leave room for side to side movement a panhard bar would allow. being a small amount I still didn't want any, it only had about 7"-8"of travel at most unless fully aired up. And this was rare.. thanks fof all the great videos! ✌️

for instance the old Citroen cars which use hydraulic assisted brakes and suspension have a tendency to slam on the ground and lose all brakes when a leak occurs. having multiple system relying on the same source of energy raises the risk of multiple system failure which can leave you stranded or worse, provoke an accident. There is another issue with brake by wire, the feeling. I used two different hybrid CVT toyotas and even if I felt the effort to blend the regen, the CVT engine brake (ratio) and the brakes, in reality it feels imprecise and uncomfortable. We're used to refined hydraulic brakes and anything less will feel rubbish. The main limit is that for a really good system to exist, it need to feel like real brake with dead range that doesn't brake at all, then the imaginary wall with some small amount of elasticity where the force represents the braking force. The issue here is that a smooth and accurate, electro-hydraulic braking system is extremely expensive, then you need the software to be spot on. I heard that race ABS system for instance sell for 10K and they give you smooth and effective braking.