How Do Heave Springs Work? Third Elements Explained

In this video we will discuss a suspension device used on high downforce racecars (such as F1 cars) to decouple vertical (heave) stiffness from roll stiffness, the heave spring. I talk about why you want a heave spring, how it works, and what you can do with it.
Facebook: / kyleengineers
Patreon: / kyledrives
Instagram: / kyleengineers
Race car consulting: www.jkfaero.com
KZbin: / kyleengineers
/ kyleengineers

[@FormulaJuann]

Legend has it once every thousand years Kyle will come out of the tyre warmer he sleeps in and make a new video 👀 already can’t wait for the next one!!!

[@KYLEENGINEERS]

There's going to be a few suspension videos with this model coming, hope you enjoyed this one! Drop any video requests below!

[@davidskidmore3816]

Please can you do a video on pushrod suspension and the predicted loads!

[@viktorhaggstrom9036]

I've seen this car on the channel before but with way less aero on top. Is this setup going to be produced?

[@Ecko20XX]

Could you do an aero analysis on the Vision 1789?

[@854gabryel]

Really interesting. I'm all in for more suspension videos

[@int2str]

Great to see another video. Looking forward to seeing more in the Yaw sensor series. I already bought some sensors myself :)

[@brawngp9443]

to address some possible disadvantage for this kind of heave spring, you have to be careful if you are using nonlinear motion ratio for your dampers/rockers. using nonlinear motion ratio with a T-bar type heave spring can result in higher roll stiffness, because the T-bar will not just rotate about the vertical axis but also pivot about the lateral axis resulting in compression of the heave spring in roll. Also your single wheel bump stiffness will increase, which may not be a problem for relatively smooth track surface on most of the permanent race tracks. but ie. for hillclimb cars, higher bump stiffness may cost you more performance that you gain with aero. in some cases it may be better to minimize your contact patch load variation than adding loads of downforce to the car, it depends mostly on the tyres you are using

[@BrodeyDoverosx]

Here we go. Last time I looked at this was in milliken and milliken

[@linusgrinde210]

Too relatable lol. 😅

[@s1nenomine]

I've seen that line on some racing simulations but never found a clear explenation. You fixed the issue, thanks :D

[@BuddyCorp]

That was fantastic, really enjoyed the animated model of the suspension. This video really got me thinking.

[@InertZero]

I have been trying to understand this concept for a decade now, since they were introduced in IndyCars. I finally get it! Thank you!

[@guttsu]

Learn something cool everyday. Hadn't even heard of this before; CAD models were insanely helpful!

[@pedroaalmeida96]

All around best automotive engineering channel, there is!! Thanks a lot!!!

[@sayan1667]

This is fantastic! We just bought Dallara F3 with 3rd element suspension and i was very curious how it works and why does it have 3rd shock with spring. Now i know and because of you i fully understand it. Thank you, Kyle!

[@johngioffre226]

Awesome video ! Thanks for taking the time to share

[@AudreyH48]

This was great! I have understood how the inboard suspension works but never knew about the heave setups. Very cool!

[@jubuttib]

FWIW heave springs aren't by any means limited to cars with inboard suspension setups, for example the McLaren 12C/650S road car uses a Z-bar type heave spring at the rear. It acts similarly to a rollbar, but since it's Z-shaped instead of U-shaped, it only acts when both sides are compressed (so for both squatting and heave in this case).

[@danielhirata4054]

Serious FSAE vibes on the aero

[@duffieldjunction6243]

Great video! Taught me more than first year motorsport engineering!

[@philipbyrnes7501]

Thank you, that was the simplest, clearest and most concise explanation of one of the cleverest mechanical solutions that I have seen in many, many years. Both setups that you put together were, to my thinking, the most excellent and elegant way that it could possibly be done and each solution perfectly suited the differing conditions required front and rear with, as you showed so well, the rear wheels that just go in a straight line can use a simpler but perfectly effective system and the sheer elegance of then setting up for the front wheels that turn and squirm in ways the rear is unable, well, thank you, I cannot tell you how pleased my mind is with what you have shared, thank you. By that I mean, with absolute respect, that in the way my heart responds when hearing a clever and very funny joke that spontaneously makes me laugh, when I hear music that stirs my soul, when I taste something that makes my knees go weak, that’s kind of how my mind feels at the moment, satiated and content having learned a great new treasure that some very, very clever person figured out and wow, good on them, that is sheer genius and good on you for showing us how clever they truly are, thanks mate, good onya from down under ,’o~)

[@bradarmstrong3952]

Wow! Super interesting and quite clear explanation! Love this!

[@YOLO-tq3el]

came for some aero stuff for uni project, stayed for the better than the professor explanation!!! GOOD SHIT!!

[@ezequielyf1531]

wow im just enter in this motorsport world and your videos are so good!, awesome bro! keep going

[@RandomKSandom]

This was way more interesting than I expected. And I came in interested to begin with :)

[@anuardelcastillo2627]

I learned so much! Thanks! great video

[@blackbandit1290]

Great video. I'd love to see you develop this further with a discussion of the mono-shock design and how it separates heave and roll in comparison.

[@philipbyrnes7501]

Yes, that is a very good question and happy to add my voice to yours in asking for that, thanks

[@kundeleczek1]

I love vehicle suspension systems. Unfortunately I know just a little about. That linkage in a front in this video is lit. Very well made video and thank for your work.

[@rmp5s]

Suspension and aero stuff are rarely talked about in relation to power stuff. Subbed.

[@TheFarCobra]

Back in the dickity day we used to run “Z” bars. Packaging on a modern open wheeler would not be great, but they may be a solution on a time attack car.

[@jubuttib]

You like to hear that McLaren actually used a Z-Bar in the rear of the 12C/650S road car for extra downforce handling. =)

[@MrJAYz1011]

Great video, I noticed in the first set up the corner springs/dampers are only really controlling the warp mode, could you go into a bit of detail about removing them for a mono-shock design please? I have always been interested in them for a weight/cost saving measure but would be interested in some of the problems that may be present?

[@nyftn]

this will help me a lot . for assetto corsa car setups .

[@Lost13mm]

Thanks for this great video - I am at the early stages of designing my own Exo road/track day car. I plan to have some wing and "ground effect" floor in the car. I was wondering if it is worth me using this T bar set up or is it only really any use with cars with large amounts of down force? If it would be good how do I work out the spring/damping for the T bar, also what size bar should the T bar be? Or is flattened tube an option so I can rotate it to change the amount of force needed to bend it (a bit like the chassis bars used on karts). Also does this system mean the suspension has an amount of anti-dive on the brakes?

[@zlm001]

I'd be interested in the different types and styles of various probes on F1 cars. Like all the metal dots underneath the Ferrari front wing seen in the picture of Vettel carrying it after a crash.

[@bloqk16]

Remarkable to see in my lifetime the changes with suspension systems on open-wheel racers. Look back at some of the F1 cars of the 1960s, such as McLaren M7A, where it had exposed coil springs in the front and rear suspension. Car builders back then, such as Colin Chapman for Lotus and Dan Gurney with AAR Eagle seemed better aware of the aero drag of exposed coil springs; where they had the font suspension coil springs mounted inboard with their F1 racers.

[@TimothyChapman]

Could you do a video visualizing the direction of forces between tire and road during a combination of turning and accelerating/braking and what happens if you do too much of both at the same time?

[@erikrummel6277]

Great video Kyle!!!!! I have a request. Can you illustrate how you would implement a Tbar on the type of rear suspension setup your model uses ? I’m looking to do that on the front of a build I’m doing and would love to see your thoughts. Thanks!!!

[@crunchytheclown9694]

great vid thanks

[@GoldenSlothRacing]

Very cool stuff. Do you know of any time attack cars in Aus running this kind of setup other than the ex JGTC silvia? Love seeing it.

[@phildem414]

Excelent explanation, eye opening on the setup options. Question: is it realistic to exploit the ride height vs downforce curve and the heave spring setup in order to implement the same effect as a flexy wing? I mean maximising down force at medium speed and trying to reduce drag at higher speed?

[@zakshah3480]

Please please PLEASE come out with your course on aero design!!!

[@Lifeof728]

Thank you

[@veronicacossor4290]

Could you please do a video on motion ratio regarding rockers increasing stiffness in bump so as to keep softer wheel rate at low aero and increasing for higher aero. This rate can be changed by rotating the rockers. Cheers Gary

[@eddyg4742]

Question: Is damping important for the heave spring ? Ie can it be just a spring rather than a coilovers, just like the anti roll Bar? Relying omly on the corner coilovers to do the damping. That way there's one less variable (heave spring damping rate) to worry about.?

[@n0ch91c3s]

Considering the heave springs are usually super stiff, I'd expect the heave damping, at least in rebound, to be similarly stiff to control it.

[@RHBTurbochargers]

to completely isolate the heave mode, yes it needs its own damper. for a slightly compromised setup you could valve the corner dampers to suit the added spring rate. many ways to cook an egg

[@jubuttib]

@@RHBTurbochargers And to add to that, it's not like having a super stiff anti-roll bar with soft main springs and matched dampers doesn't come without side effects. Ideally even an ARB would be damped separately.

[@timothygooding9544]

what program is this? amazing video, complex linkages are something I've wanted to try an wrap my head around for a while

[@lltany]

Maybe I missed it but it wasn’t clear to me how the heave setup you showed allowed for independent adjustment of heave and pitch. It seemed to me to be a heave/pitch sdu. Are there setups with independent spring/dampers for heave and pitch? Is there any benefit for that? I imagine an independent heave setup would necessitate a front and rear interconnect of some sort. Is that the case? Cool video! Thanks!

[@Stephenc4877]

Really could do with your help on my Pulsar build, I’m moving the rad to be back I’ve got lots of options for ducting but I have no idea what who be best in terms of not having a negative effect on aero.

[@RRninja-jq6lp]

What do you think about using air bag suspension with ride height sensors to achive simular effect ? In road car based suspension systems retrofitting a air bag seems to be easier than 3 shock pushrod suspension.

[@marcelserra8792]

Hi Kyle, which programme are you using to illustrate your fantastic explanation? Thank you very much!

[@tylernorton8087]

first you got me interested in aerodynamics, now you got me interested in suspension. I wonder what it will be next!

[@miles11we]

He has some good videos on composite materials. Carbon, glass, etc.

[@BeyReaper]

Hey Kyle I know KZbin probably isnt the place for this but i am having issues testing 2D simulations with an fsae undertray. The data trend I'm finding shows the most downforce on the 2D under tray happens at a 0 deg inlet angle and this data doesn't match with an FSAE paper I'm trying to replicate. Is it possible to help with this issue with my simulations or to direct me to good sources that could shed light on what part of my simulations is causing my issues?

[@n0ch91c3s]

I like that the heave damper eyelets are counter rotating

[@joevarga5982]

8:22 What do you mean, the heave spring doesn't act at all in roll? The vertical tube of the T-bar is an anti-roll bar. If it's so rigid that it doesn't twist, as one wheel lifts 2", the lateral member of the T-bar moves straight back and the other wheel will lift 2" as well, compressing the heave spring.

[@salmiakki5638]

Is the 3 element a spring-damper element with all the different adjustments (high/low speed, rebound, pretension etc) that usual suspensions present, or is it something unnecessary and left aside?

[@MrSos2000]

do specific race aero/suspension alalysis videos.

[@danielpinto8591]

Fantastic. Does anyone place the other shock to only work from roll? Maybe from bell crank to bell crank but on opposite sides of the pivot?

[@patrickdasbrot7819]

Great video! I wonder with which Programm this was made?

[@GrayAirplay]

Most if not all of the major CAD packages have kinematics tools (E.g., Catia, NX, Creo, Solidworks, to name a few)

[@MrCarlozan96]

Awesome video Just a quick question: how does the system you showed in the front allow for the movement of one wheel independently?

[@hunterhach7533]

Same way a "regular" suspension setup with anti roll bar would. Compression of that side and simultaneous change in the anti roll / t-bar twist.

[@miles11we]

9:45 is when he shows specifically that

[@kingduck1947]

did you try and use the animation tool in fusion instead of using the drawing board?

[@coin666911]

Can you do a video on the yamaha ox99 its a interesting design with a very weird front wing

[@hunterhach7533]

Hello Kyle, excellent video as always. I am however curious what that 4th suspension mode is. I can't seem to find info online. Roll, pitch, heave and (?). I can't seem to make out what that word is! Thank you!

[@nizm0man]

Warp?

[@hunterhach7533]

@@nizm0man oh I bet that's it! Thanks!!

[@CaptainSteve777]

I have a topic for you. You are right downforce increases with the square of the velocity for traditional wing elements, but for ground-effect cars, downforce also varies with the height of the car's skirt, even at a constant speed. Your thoughts? Personally, I think this is the origin of the current porpoising problem.

[@samirsuleymanov2099]

One question, what if you remove the two springs at the back and only have heave spring in the middle?

[@rciwog5758]

Hi qucik question does anyone know what program Kyle is running for this video thank you.

[@samueljayachandran2849]

Is it possible to run a high aero car very high off the ground and (highly) effectively use vortex generators to seal the underbody/tunnels/floor and also prevent rear tire squirt with the same vortex?

[@VictorHugo-pr7fr]

can you explain the integral link rear suspension?

[@truekera]

@KYLE.ENGINEERS Where from you got this graph with a maximum downforce @ 45mm front height? Looks like so weird

[@Markusgebvor]

One questions after having thought aber the anti-roll-bar… is the anti-roll-bar mechanically (as the levers are arranged) not an anti-anti-roll-bar 😅? Because, if one wheel moves up, the other wheel moves down… so, the only tendency to resist roll is due to the torsional resistance? Couldn’t this be improved by arranging the levers in a way where mechanical arrangement and forces support anti-roll?

[@markmrabu9032]

What software do you use for the simulation?

[@antisoda]

Nice one. I know what to experiment with my old Lego F1 car I have laying around somewhere. It has probably been done before and might not be suited for this car anyway, but who cares? It's buildin' time! :)

[@F8Tributo]

There's a lot to this!

[@davidelliott5843]

What about tuned mass dampers? These vibrate opposite to the main vibration cancelling out the movement.

[@tturi2]

so on a regular car, it would be something that looks like a push bike rear spring and shock mounted in the middle of the front swaybar on a certain length of lever under the engine?

[@juanordonezgalban2278]

So from what I understood this can be implemented in hydroneumatic suspensions, like the ones used by mclaren?

[@TheGamingHungary]

Are so-called third sliders the heave dampers in other words? I have a sim car to set up and under the third spring, there is a third slider deflection readout. Is it the heave damper I assume then?

[@eddyg4742]

One important thing to note as well is that heave spring makes the anti roll Bar less effective. When the car is rolling the ARB now has to work harder fighting the heave spring to lift the other wheel. So heave spring stiffness increase must also be accompanied by ARB stiffness increase to compensate.

[@NZrider100]

I don't think that's true. You could lock the heave spring assembly, reduce the roll torsion spring stiffness to zero and roll the car side to side by hand. They're independent as far as i can tell.

[@andylopez1072]

Hey, you probably won't read this but what do you think about the car that Mad Fórmula has presented for this season of formula student?

[@bertram-raven]

How would you construct a Collapsing Heavy Spring? That is a heave-spring which will resist compression until the down-force reaches a certain level and then collapses at a controllable rate.

[@JamesDoylesGarage]

Would this ever be used in a road sports car? Thank you

[@carbo19]

This is so relevant to what is happening now with the porpoising on the new car. What if there was a mechanical way to control the damper on the heave spring relative to ride height? ie. much more dampening when car ride height is compressed beyond optimal? maybe even on the independent dampers on the corners? just to keep the bouncing frequency to less than the oscillation for that track. is this possible? and is it legal?

[@spacered949]

Haas’s rear has two stage heave springs. There was a F1 tech talk about suspension that mentions it after Micks Monaco crash

[@whcwcjecjecuecuw6654]

The system at 11:14 does not have any anti role effect does it?

[@samueljayachandran2849]

how do dampers switch the damping intensity/viscosity of fluid medium for fast vs slow bump, rebound. Is it possible to have a suspension that will be gentle on the drivers' bottoms (and allow for easier vision without porpoising shakiness) and still maintain stable aero platform (kinda like how f1 drivers would like the 2022 cars to be)?

[@NBSV1]

There’s different valving designs. One style uses discs as the valve. Small bumps don’t deflect the disc as much so the shock can stay stiffer, large bumps deflect the disc more so it softens the shock. A different style can use different orifices so the stiffness of the shock can change over its travel. Those are more common in offroad racing where you’ll want a shock that lands good from a jump at full extension, but also does good over bumps in the middle of travel. Shocks become magic and are pretty complicated for something that is also simple.

[@anbu999]

Do something on Nissan delta wing please

[@SadMarinersFan]

This was really cool to learn about but there's still one thing that's puzzling me. How would a team set up a non linear spring so that its got linear motion up to around 150kps, then suddenly drops 2-3 inches then goes back to linear motion like what was on the Mercedes in 2021. I just cant get my head around how you can get a traditional spring or torsion bar or react like that.

[@anidiotinaracingcar4874]

At the rear, that heave spring/damper does anti squat too or you'd have another system for that? (And same question for the front)

[@jubuttib]

Since the front and rear aren't connected, the heave springs at either end also act in squat/dive as well, yes. A "heave only" system that doesn't affect squat or dive would be an interesting thing, kinda like a Z-bar between the front and rear suspension...

[@joelgreen1475]

Does the third element helps pitch? Like when the vehicle is under heaving braking and the vehicle starts to pitch forward. Would the third element help to prevent the vehicle from bottoming out in this case if you have a very low ride height?

[@AndrewFrink]

yes it would. It's only connected to the one axle so if both wheels move in the same direction the heave system comes into play. As you noted, yes this could help prevent bottoming out. All of this design should become even more important for F1 cars in 2022 due to the move to 18" wheels and lower profile tires. Meaning that less of the suspension travel will be made up but the tires squishing.

[@joelgreen1475]

Thanks very much

[@laurean5998]

If you have the heave spring and the torsion bar for roll you could just leave out the 2 "main" springs, right? Not that this would make a lot of sense considering you have to keep the dampers anyways...

[@XO43137]

What about pull-rod suspension?

[@TheDamian58c]

Now I wonder, how to tune heave stiffness without affecting the pitch stiffness? Or rather how to isolate heave from pitch (in the way that this video showed isolation of heave from roll)?

[@jubuttib]

Yeah, that'd be an interesting thing... The one solution I can think of, off the top of my head, is a Z-bar type system that connects the front and the rear suspensions' heave modes... Basically you'd have a Z-shaped bar (very much like a traditional anti-roll bar, except that when one end moves up, the other goes down) that's connected to the heave modes of the suspension at the front and the rear. In pitch, when both front corners compress, it pulls up on one end of the Z-bar, which pushes the end that's attached to the rear down, all in all not really affecting pitch (at least if the linkages are designed properly...), and in squat the reverse happens. But in full four corner heave, both ends want to go up, which bends the Z-bar and makes it act as a spring.

[@TheDamian58c]

@@jubuttib Yeah, that could be a solution, but I wonder what kind of solution is actually used in cars like F1, if it's used at all. I can see some problems with the solution you commented about (if I understood it correctly), like the stiffness of the bar and ergonomics of its connections to the suspensions and the chassis of the vehicle (I understand it being a z shaped beam where its ends are connected to the front and rear suspensions, and that there's a pivot point connected to the chassis). If I'm not mistaken, I think I've heard of a hydraulic system connecting suspension rods of each wheel together, and controlling pitch, roll, heave and warp parameters with valves. Of course that kind of system has complications of its own. Other than that, I can think of a cord system, which would connect to each wheel's suspension to each other, and each cord would have a spring which would control either the pitch, warp, heave or roll characteristics, depending on which wheels is the cord connected to. I'm kinda disappointed that the video actually discusses pitch springs rather than heave ones, there would actually have to be something connecting front and rear suspensions, and that something would need a spring, for it to be an actual heave spring.

[@jubuttib]

@@TheDamian58c I think F1 uses something akin to what was in the video, pretty sure they do "heave" via having 3rd springs front and rear. I haven't heard of any cars IRL that would have a fully separate four wheel heave system, beyond MAYBE something like the inter and cross connected hydraulic system of some McLaren road cars... I don't think the added complexity and weight is worth it for most racing applications. It is an interesting thought however. Also FWIW I do work with vehicle simulations, and have had to look up lots of different suspension layouts over the years. Not saying that I know everything (FAR from it) but I have had a gander at a fair few.

[@joaquins90]

What about heave vs pitch? I guess there's no way to distinguish them without some front to rear connection, but maybe I'm missing something.

[@5thearth]

No, you're right. You need a front-rear connection for that. You could use an anti-roll bar type setup, except oriented sideways to connect the front and rear, or do it hydraulically like some F1 cars did before it was banned.

[@bigpooporder3965]

Ohhh that's how GT (BRZ SuperGT) cars suspension setup. I know the general idea from logic, and FormulaE yt video but, I dont know the detail of "why need 3 suspension?"

[@sam90o48]

make a video on PEUGEOT 9X8 how can they have a car without a rare wing, ik it is possible but how effective it is, KYLE plzzz

[@martin_in_the_alps]

I remember Gordon Murray saying that that to much downforce leads to a stiff suspension on road cars. I always thought there has to be a solution to that.

[@miles11we]

There is also unsprung aero

[@E9X330]

That's probably why Koenigsegg has a system like that called triplex

[@truthseeker8483]

Hydropneumatic spring-less system with self levelling and linear spring rate would be far superior...retaining perfect ride height and mechanical grip without compromise.

[@mrlazda]

Active suspension would be even better (pure hydraulic) and it was us in formula 1 in early 90, before it was banned. I do not know why in non restricted series is not used now, electric moved long way in last 30 years so making active suspension now is trivial thing.

[@truthseeker8483]

@@mrlazda Hydropneumatic is hydraulic only with pressurized Nitrogen as the spring

[@mrlazda]

@@truthseeker8483 I know what is it, I even drow car with it like 25 years ago. But problem in it is gas, you do not want not controlled spring that why in f1 they did not use it even on road car it is in use from early 1950.

[@fillman86]

wait, I'm confused. Wouldn't the T-bar induce roll? sure the torsion spring would reduce it, but 1 wheel being pushed up (during roll), pushes the other wheel down.... inducing more roll...?

[@mrnebstar]

No because the T-bar is pivoted in below and therefor not in fixed state where it pushes that T-bar other direction on the other end. When one wheel is pushed up that side of T-bars upper end is moving forward and it's torsion spring tries to fight it back and same time it moves the other end of that upper side of T-bar forward and thus tries to level other wheel upwards. Just like antirollbar. Don't know if this is in any undestandable form since my english isn't the greatest (not my native language). Edit: That animation without third shock was kinda bad because it didn't show that torsionbar moving back and forth and twisting under load.

[@tensevo]

In summary, if I understand correctly, you would want to bottom out the heave spring a little before the corner springs bottom out, for purpose of ride height control.

[@shadowninja569]

woo boy

[@Vehicular.Shenanigans]

You’re a badass ❤️

[@DFX2KX]

huh, I've never heard about wanting different behavoir for all four wheels vs just two of them, nor how that might be accomplished.

[@jeltesteur8286]

Now it seems Redbull and Mercedes also were able to create such a non lineair stiffness in their wings End of last year. How would that be executed?

[@jeltesteur8286]

Awesome video btw

[@The_Pocisk]

So how stiff are F1 "springs" (F and R), 150N/mm, more...?

[@km6832]

People asked for a video on turbo fans. He does a video on heave springs

[@ASJC27]

Turbofans as in jets? Why would he do a vid about that? He talks about race car stuff.

[@bobbydirtamiyer2151]

I want to see what this would do on my RC car.

[@thethinkerer]

Anyone else catch that spinning eyelet on the front heave spring?

[@dirtrider88]

what about the 5th element?

[@Velocitist]

3:52