Why Modifying Your Suspension Often Isn't Worth It (Road Cars)
Can suspension upgrades like springs, dampers, coilovers, and sway bars make a difference?
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Are suspension modifications worth the money? In this video we'll analyze how cars get grip, what impact suspensions play, and the test results from Tire Rack testing four different suspension setups: 1) Original equipment suspension on a BMW 3-series. 2) Lowering Springs. 3) Springs, dampers, and sway bars. 4) Coilovers (using stock sway bars). We'll discuss differences in noise, ride comfort, handling, cornering stability, steering response, braking modulation, handling predictability, cornering grip, slalom times, and lap times.

We'll also discuss why investing heavily in suspension setups can be worthwhile for racing teams, but often those reasons won't apply to road cars. Ultimately, it's important to understand what reasons make sense to upgrade a suspension, and where you might be let down. Modifications are always about setting realistic expectations and meeting your goals; I hope you find this video helpful!

Tire Rack Test Results:

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  • Marlon Hernandez
    Marlon Hernandez

    Disappointing video.

  • lolus pololus
    lolus pololus

    yep all true , we like spend money on kind of updates and drive to work and for cup of coffee

  • Brad Choi
    Brad Choi

    So why would someone spend all that money on suspension upgrades when there's such a small difference? Same reason people buy expensive performance cars then sit in rush hour traffic every day, or buy an eight bedroom home for two people.... because they can. LOL!

  • russ Thomas
    russ Thomas

    This seems more like a tire test. 4 of the same car, all cars have a different suspension but all 4 have the same tires and all 4 have close to the same times. I bet a ZR1 wearing the same shoes would have a similar time. Thinking better tires would show a bigger difference.

  • Ariana

    If you can actively change the dynamics of the car then I think that may affect the calculus here. For example, on my old Civic Si, which I used to Autocross with, I went with significantly stiffer, custom spring rates and high quality dampers. The goal not merely being to decrease body roll or dive etc, but to increase the tendency to oversteer. Being a FWD car, the tendency to under steer was high. By changing the suspension setup I was able to change the tendency to be much more balanced, and even a bit biased to oversteer, helping the car to rotate during cornering and overcome some of the drawbacks of FWD. There can be reasons to change suspension setup, but I think a concrete goal and plan is needed. “Just lower it and make it stiffer” probably isn’t going to offer you much performance benefit.

  • Ryan

    Tires are the main thing that effect performance. Suspension just helps you handle the grip better. Like keep the car off the bump stops in corners with sticky rubber. Stock springs with PS4S would do just that on my car. I ran a set of slightly stiffer springs with a mild 0.8" drop. Later added some Bilstein B6s to handle dampening for ride quality purposes. Handles 300TW tires perfectly with a slightly more firm ride.

  • Mr. 2 minutes
    Mr. 2 minutes

    how about reliability? i have and eye on rally suspension

  • Matt Canton
    Matt Canton

    How does this analysis change when you have significantly stickier tires? I've always understood tires >> suspension for grip, however, to take fill advantage of that additional tire, you need to stiffer suspension. Would you still see a 1% difference or would the delta be higher? I would assume most OEM vehicles tune the suspension for the OEM tire.

  • Jim Knowles
    Jim Knowles

    So Jason As stated in other videos you (and others) find great pleasure in the current Mazda miata and that evokes the pleasurable driving experience even at a low speed. I am very curious about your opinion of driving a well tuned miata .....say a flying miata "decker suspension " package...?? vs your stock ND miata. But both must have the same "decker" tires and wheels

  • DaBinChe

    My OCD keeps eyeing the driver side wind defector not fully seated.

  • DatBoi correa
    DatBoi correa

    I think the problem is that the test car is a new, and a factory modified M3. Older cars will see a bigger improvement.

  • Manuel Martín
    Manuel Martín

    Too much people modify their cars without the ability to extract to maximum potential of the standard version of them. So if its an old cheap car do it but, if you start with a good base maybe a sport drive school is better buy than a fancy coilovers an low tires. When your abilities will better than your car, you gonna know what parts buy and don't waste your money and your time

  • Kenshō

    When you go on a ride, you don't corner only to one side... So... weight transfer will have a big difference with an aftermarket suspension. Handling... Basically , if you want something comfortable, stay with the original. If you wan something for track day, or cornering on the mountains, get something good and adjustable..

  • Code066

    How in the world is he able to communicate all this data while driving??

  • noahman27

    Very interesting! I will say that on my old VW Rabbit, I put bilsteins on all four corners and boy that car was just so much fun to drive. It was like magnetized to the road. It gave the car a really fun, zippy, sporty personality that it did not have with the normal struts/shocks.

  • 1979wazza

    I wonder if the numbers would be different if they had used a more typical car than a BMW? I also think things like body roll were overlooked. I remember my old car was a pig for body roll and would end up fishtailing when taking corners sideways until I did the suspension and both wheels would let go together and grab traction together; greatly improving control. I grew up and don't do that anymore, but I still enjoy the occasional thrash and will not buy a car that doesn't have some kind of sport suspension, I don't trust a car that bounces around and doesn't ride flat. That being said, my car is about 700kg heavier than his Mazda, body roll is probably less of a concern for him.

  • Ali Dawood
    Ali Dawood

    These mods will make u feel faster and as a result give u more confidence to push and ultimately actually drive fast and I’m pretty sure make more of a difference at high speed cornering

  • Tim Bartholomew
    Tim Bartholomew

    Where is the white board?!

  • Ko-wing wong
    Ko-wing wong

    Idk man..here in Canada a good set of adjustable dampening coilovers would work a miracle in our four seasons. Soft in the winter, hard in the summer...medium soft when driving on forestry/gravel roads. I think it makes sense in my country.

  • Dave S
    Dave S

    I think a key point has been missed here. Not many people take new suspension off of a car to fit coilovers. By the time coilovers are being fitted, the old suspension is probably due to be replaced. Now in the case of those Bilstein shocks on your car, price them up with a set of matching springs and of course top mounts, as decent coilovers come with these. Then compare them to the price of the coilovers. Then the adjustment offered also offers a benefit, if setup right. I also don't like the fact they made it about suspension and then only changed the anti roll (sway) bars on 2 of the tests. Seems a bit random and not a direct comparison.

  • atfsgeoff

    Suspension upgrades are a financial black hole. Unless you spend as much time adjusting/tuning your alignment settings and damper rates as you do installing the the parts, you won't get any performance benefit out of it.

  • Mark Haury
    Mark Haury

    This is exactly like people putting loud, low-restriction exhausts on their vehicles and thinking and asserting they are increasing the power when in many cases it actually decreases power. An engine is a very complex system, and changing one thing without understanding how everything works together is a very common mistake. Changing the exhaust without also changing the intake, tune and other things like valve lift and timing is often counterproductive.

  • Justin Allen
    Justin Allen

    donut media did a video on installing aftermarket sway bars on a miata and it made a real numerical difference besides just feeling


    It’s good to be informed on the results of mods. I think feel IS worth the cost, just like buying an exhaust to make a car sound more aggressive even if the performance gains are marginal. The only reason for buying a sports car is because it triggers and emotional response when driving it, if a mod makes the driving experience more enjoyable then it’s worth the money. :)

  • Look Closer
    Look Closer

    This is not a good test because it does not show the quality of performance suspension. Put OE suspension on a race car and lets see how it does. All I get from this video is that you are saying that suspension doesn't matter. If that's the case then why do race cars don't use cheap ebay suspension?

  • Piyoti LaHound
    Piyoti LaHound

    a suspension on my old mustang made the car controllable ... it has excess body roll, something that was not correctable by sway adjustment. but in a more reasonable car like lets say a bmw.. it more than likely would not need modification .

  • chrislox1

    You just saved me £500! Thanks.

  • Jeffrey Ball
    Jeffrey Ball

    Grip does in fact come down to the tires and the friction between them and the road surface. A "high performance" suspension may overwhelm the available grip of the tire before its benefits are seen. Doing this exact same test but with a higher grip tire might show drastically different results. The feedback given was that the "feeling" was different and to me that is an indication that the is potential there, but possibly not enough grip to take advantage of it. I'm not an expert, and the data may show otherwise, but I'd like to see what happens. On a side note, different suspension settings (springs, dampening, etc) do affect that geometry and may not allow the vehicle's designed suspension work in its most efficient zone. Softer springs might be good, but if the camber curve for instance, is reducing the contact patch, then it's worthless. You can't test all of these things in an experiment. They had their variables and their control group, so this is what they have to show.

  • Bert Hogendoorn
    Bert Hogendoorn

    how can suspension upgrade reduce road noise (tire noise), is this a viable choice especially in EV's? Or just focus on teh tires (profile and manufacturer special quite designs)

  • GabrielTheGray

    A surprisingly poorly supported claim. Grabbing test data from a BMW 3 series? Why not compare the stock suspension on a Corvette to aftermarket options? I'm sure that will show little difference as well. It makes more sense to test this claim out on cars that are not so well setup from the factory, that have parts designed to meet a price point rather than a performance target, and that people tend to upgrade.

  • Leigh Harwood
    Leigh Harwood

    I don't for one moment believe that a lower centre of gravity and less body roll does not allow you to corner faster. Clearly the 'tests' are rigged to sell tires.

  • pax1880

    I'm a little late to the party BUUUUTTTT I think the real takeaway here is BMW's 3 series OEM suspension is pretty damn good. This fact may not hold true for other more affordable vehicles.

  • FlameHazeist

    Only worth it if you're racing or doing extreme stuff like 10+ ft jumps!

  • Julio Rodriguez
    Julio Rodriguez

    📉📉📉 Aftermarket suspension sales after this video. 📉📉📉

  • Franco

    Thanks for the info, I was debating going with an upgrades Bilstien system for My LGT wagon and returning to stock height. Daily driving on stiff springs is getting to me and all for 1” lower stance.🤪🇨🇦

  • Patrick Nelson
    Patrick Nelson

    13:10 - This “ok, but *really* …” part I relate to so much, as a software engineer too. I find myself saying this a lot, especially this way (lol). We can refactor and refine the code so much, but at the end of the day, was it _actually_ worth it (considering the expense of time)? “Over engineering” sometimes takes a bit of experience to learn to avoid properly.

  • Steven Mitchell
    Steven Mitchell

    Changing bushings from rubber to urethane as well as coilovers and tuned dampers has a definitive effect on the handling of the vehicle. SCCA competition proves that regularly. Granted, unless you are competing or are a very aggressive street driver, the effects can be minimal. Skidpad and slalom are fairly useless tests. Roadcourse testing is definitive.

  • TT-RS

    Actually, missing your yellow bird S2000....... that was that much more appealing to me.....

  • cody crosby
    cody crosby

    Your ND looked so good in yellow I just had to do it too!

  • Jason

    This is why I love your channel. You like proof through real testing, not just giving opinions.

  • TheBowerbird

    Nice takeway here is that coilovers are trash.

  • TheMattbrownbill

    It's very important for sales reps driving between appointments to feel they are 1% faster than they could be... Just think how many more customers they could visit in a day.

  • Sagich Euchnicht
    Sagich Euchnicht

    Have you considered the driver itself? I'd say (from my personal experience) that Suspension Upgrades and better Suspension make the car more predictable and easier to drive and corner. Those Upgrades might not be able to improve grip, but make it easier to drive near the end of Grip. When the testing was done by a professional driver (which I would assume) he might have the skills needed to drive all Setups at maximum Grip-Capacity, but for the average driver it still might be very benefitial to better predict how the car is going to react.

    • Sagich Euchnicht
      Sagich Euchnicht

      If roadcars should be driven near the redline for grip, thats another discussion^^


    Well done!

  • Lyfan Deth
    Lyfan Deth

    You may have missed one point. BMW has already invested heavily in a "performance and comfort" suspension. When an OEM makes the effort, aftermarket parts will rarely do better. But on a midmarket car that hasn't been as highly optimized? Aftermarket will often improve it. Tirerack only tested one model. That's a statistically invalid test group.

  • Cameron Naidoo
    Cameron Naidoo

    Okay but I'm curious, does it improve driving stability/reaction on the road? Like would I be able to better control my car when it's tending towards being on edge?

  • Bill Lemon
    Bill Lemon

    Which, if any, mods would better communicate approaching the limits of adhesion? For most of us, that would allow us to go faster safely.

  • Hreb

    Additionally we don't have any data about whether adding power (or changing any other variables) makes suspension changes more or less valuable. BMW could have put the same suspension in the M3 as the 328i, but they don't. Is the M3's suspension only 1% better? We don't know.

  • Hreb

    So from the tirerack data we can conclude that the BMW 328i had a good, well-tuned suspension for track use. Two important problems though. 1. This doesn't tell us anything about whether the OE suspension on your EJ6 or DC2 is any good. 2. None of the tests examine the suspension's performance handling bumps, potholes, or other scenarios where the suspension will have to be responsive in order to maintain performance in a reduced-traction environment. If I drove around on racetracks all the time you can be sure I'd be willing to make different compromises as compared to real-world highways and interstates (and real-world weather!)

  • joe schmo
    joe schmo

    BMWs are engineered to handle well, so you may find better results with lesser priced cars. and Note: (not to bust your chops), but it's ANTI-roll bars or sway bars.

  • Ziggy Freud
    Ziggy Freud

    Once again excellent vid and thought provoking - suspension set up needs to enhance confidence in the driving experience hence different stokes for different folks - OEM is the best compromise for the masses and per dollar - the driving experience is such a personal thing.

  • al_in_philly

    And yet you switched out your original shocks/struts for a set of Bilsteins. . .

  • Ali Al-Qurtas
    Ali Al-Qurtas

    Thank you for the informative video, and being an honest guy.

  • Frank Montana
    Frank Montana

    Jason, you are comparing alternative suspensions on a new state of the art BMW. But how about a vintage muscle car? I have a '69 Mustang Mach 1, 428 Cobra Jet. I was thinking to go to coilovers.

  • Boyd The Goofball
    Boyd The Goofball

    Using cheap non specific wheel spacers is one of the worst suspension modifications you can make. Been there, done that. Search for my Ranger Cobra wheels with spacers video. The steering pulled left so hard under braking that I removed them after one day.

  • GBass

    One thing about the TR test and using the results in this video: They base it on only Eibach spring and damping tech for street applications, not the best available.

  • GBass

    It would be cool if you could do a similar test to the TireRack test ie: Ohlins DFV, JRZ RS, KW V3 etc on your car. Ones that have have diff approaches to damping using those various dynamic tests. See the Spanish Moose Test slalom videos on YT. Very cool extreme avoidance testing.

  • 100rats

    but wheel gap ugly

  • Collin Wall
    Collin Wall

    These are good points, however I think that on a car from a company that is not built by a people that prides themselves on selling “the ultimate driving machine” it would make more of a difference, or on an older vehicle too

  • Nico D. Sun
    Nico D. Sun

    I never heard of a street car or race car (tarmac) being limited by it's suspension.

  • Andy Abram
    Andy Abram

    The best evea ,, like Mike Tyson

  • 3 8 Flower (T)
    3 8 Flower (T)

    I put KW Variant 3 coilovers on my Fbody, now i have a little bit of bump steer? Is this because the angle of my steering linkages have changed? How do I address this?

  • Teddy

    suspensions isn’t always for fast lap time. like the KW v3 advertise for Street performance which basically means street comfort. It turns a bumpy sports car into an enjoyable dd. But ride comfort measurement is very subjective...

  • sultanabran1

    big car manufacturer with millions of dollars of R&D designs a car. little company comes in and says 'my suspension is better'

  • AutoFocus Cars & Vids
    AutoFocus Cars & Vids

    So, do you think these 1% difference results also hold for manufacturer released products like Porsche's X73 Sports Suspension for the 981 Boxster and Cayman? And if not, why not?

  • Roger Brooke
    Roger Brooke

    Nice day for a drive in the Oregon countryside.

  • TheDemonican

    Flyin' Miata has a set of their Fox Coilovers, talk to them about it!

  • Alan Fish
    Alan Fish

    So, did you fix the wind deflector between the seats after watching this, or are you a monster?

  • Hawke Allen
    Hawke Allen

    I once ubered the guy who started BBS. He said that they could put heaps of power on a car and it would change the track time by only a second or two. Where as by dialing in the wheel, tire, suspension setup they could drop their time by 10-20 seconds per lap. I think the key to it is having grippier tires, because the tire will lose grip at the same speed no matter the suspension. He was definitely an advocate for suspension upgrades over power upgrades to improve track time. It just depends on your individual goals for the car.

  • Hawke Allen
    Hawke Allen

    Yeah for parts alone pre-tax on my shocks is ~3300$ so coilovers are the way to go for me lol.

  • Brian Lee
    Brian Lee

    Easy answer... It's more fun around the twisties!

  • callmekitt

    Well, I reckon your Bilstein B6 are better than most series standard coilovers. I get what you're saying, but arent you contradicting yourself a littel bit: when driving a street car, where performance doesnt "matter", isnt it all about the feeling than? And thats where new suspension come in. My Porsche 996 got the Öhlins Road & Track kit, which transformed it into a whole new animal. Im not talking about performance but it feels rejuvenated by so much! Its a sundays car, with 40k miles, old suspension was still like new. Liked the Video, where you talk while driving, keep it up!

  • Aaron Eaton
    Aaron Eaton

    Where are you driving at in this video? Looks kinda like the Red woods!

  • Stephen Maher
    Stephen Maher

    There's also the use case of a very old car with suspension that's worn out and needs replacement or improvement. Even if it isn't an improvement on how the car handled when it was fresh from the factory, it could be an improvement in handling and reliability for a 20+ year old car.

  • Tristan Hanley
    Tristan Hanley

    Sway bars are probably the best thing to change from a stock suspension. If you aren't going to go a full(including arms and things) kit then the sway bars will have minimal impact on bump performance and NVH in terms of comfort, but can really improve body roll characteristics.

  • Sabine Fernando
    Sabine Fernando

    best suspension for city's with potholes? eg: Montreal

  • Zack Y
    Zack Y

    it was because your ND’s suspension was already quite good ;)

  • Christopher Harper
    Christopher Harper

    Nice look, and great points!

  • Ashanti Ali
    Ashanti Ali

    Only makes sense to replace suspension if your in a car with over 200k miles. I bought a magnum RT which had absolutely trash suspension. My mechanic was like “it’s going to cost alot, more than what the car is worth. Usually I say buy another one but at this point every dodge magnum out there is going to be high miles due to their age and will need suspension work anyway.”

  • Brad M
    Brad M

    Jason - given that the car's weight, engine, and brakes are fixed.... isn't it reasonable to expect lap times would be similar? In other words, a 1% improvement is in the expected range of improvement? And then the suspension change comes in at "feel" and "confidence" moreso than some major change in lap time? A suggestion - what's the most efficient way to change your lap times? Tires? Chip? Exhaust? Suspension? After taking my ND2 through some local canyons and being totally impressed, I am putting off my planned suspension changes. I like the stock bilsteins just fine for what I'm driving now!

  • Ian Ozborne
    Ian Ozborne

    But air suspension goes pshhhhhhh and I want that

  • John G.
    John G.

    This may be a valid study for newer vehicle but if you take and outdated aged chassis, make the same modifications, you would feel a greater difference. Tirerack should test that on my rust bucket. 😂

  • Indisputable Ltd - Kenya
    Indisputable Ltd - Kenya

    I think that you are completely missing the point. NONE of the tests you describe is really getting to what good suspension needs to do. Think about it this way. You are pushing on, and crest a brow mid corner, perhaps at high speed. Unbeknownst to you, just over the brow, the road surface has some surface imperfections, AND, you find, a camber change. One end of you car steps out, and you, not being Lewis Hamilton, snap the throttle shut. Now, THAT would be a suspension test, and the measure of "performance" that you are looking for, is how well the suspension can keep the tyre's contact patch connected with the road surface, so that either the chassis design / stability system / driver skills, can work to their best, to stop you ending up upside down in a ditch.

  • Collin Webster
    Collin Webster

    I think this is a great video and it’s some thing for us all to keep in mind. That said I do think there’s one potential flaw in the testing: tires. I suspect that the stock suspension and stock tire combination were already optimize to work together and that any potential improvement from the other equipment were mitigated by the tires not having sufficient grip to perform better. I wonder what would have happened if they had gone for an extreme performance summer tire (not some R compound track tire) would the grip the tires have enable them to take advantage of the suspension Upgrades and would it have shown the true limits of the stock suspension?

  • David Sherley
    David Sherley

    A noticeable decrease in body roll in corners and in the car pitching forward under breaking is a significant achievement from a well sorted upgraded suspension system. That increased stability gives the driver so much more confidence in pushing a car, no matter what of Tire Rack’s numbers say. Perhaps the BMW wasn’t the best choice of cars to test. I have a ‘90 911 that’s been upgraded with a well sorted system of 2way adjustable Coilovers, stiffer sway bars, mono ball bushings and wider tires. The ride is neither rough or noisy. The difference in handling is night and day. Because I have so much more confidence in the car’s stability, I can take corners far faster than I would dare with OEM suspension.

  • L. Carroll
    L. Carroll

    I put Bilsteins on all four corners of my FJ Cruiser to reduce body roll and got a ~20% improvement in my wife complaining about being carsick. Not the 100% improvement I was looking for, but worth the $400 in parts. Plus I FEEL faster.

  • V0V4P

    So, you're saying that upgraded suspension feels better, but doesn't improve performance. I'm fine with that, because I'm driving a car that has nothing in common with performance, but it feels great with upgraded suspension and tires.

  • Macéo Capietto
    Macéo Capietto

    Wining 3 tenths in 29 seconds is a lot, in a track lap it's a second more or less which is an insane improvement and you can feel you are able to keep more speed and have a better balance. Even if the numbers are small the difference is big !

  • Paul Cooper
    Paul Cooper

    I mostly put coilovers on my MR2 because the original suspension was worn out/past it and was cheaper than stock. Finding out the spring rate ratio was the hard part. I set the ride height to stock, the dampers on the softer side and the car feels nicely planted. Incidentally, with less drop at the back under acceleration, does it improve 0 to 60 times?

  • Robert Singh
    Robert Singh

    Jason, I would love it when you do these videos if you could also go into any limitations the test might have had. I.e. did they adjust the geometry and do roll centre correction properly for the aftermarket components or did they just slap them on there and test? Otherwise, thank you for helping keep the internet somewhat professional when it comes to car stuff

  • Logan Huwe
    Logan Huwe

    truthfully in a road car you shouldn’t ever find the difference between the .99 g and .98 g

  • Logan Huwe
    Logan Huwe

    3 tenths of a second on a 30 second course is pretty good imho. but if this is for a street car that, even if it’s gonna be tracked once a month maybe that’s still not worth it

  • Fred Flickinger
    Fred Flickinger

    Having owned a few 330Ci coupes with the sports package, I can say that with stock suspension tires can make a huge difference! BTW Jason, how do you like that lift you were showing lifting your Miata?

  • ppernett1

    Well, Tire Rack kept the same wheel and tire combo. Makes sense for the test they were doing, isolating variables. But also in the real world scenario, suspension upgrades can help you take better advantage of something like tires. So it’s not so much that those upgrades alone do much, but they allow you to stack up the minor benefits of each part to make a huge difference over all. Most of the time we do it because it’s a hobby and we like it. Most of us are not thrashing our pretty cars all that much. After all they aren’t cheap and we want them to last.

  • Z-Twinturbo

    man I wish the road was that empty when I go for a drive :(

  • Ian Jepsen Ely
    Ian Jepsen Ely

    In a road car the difference will be more on the looks than anything else...

  • FlyFarther

    I had no choice but to mod or replace the suspension on my POS 2013 elantrash gt .

  • - RedTango -
    - RedTango -

    Kids nowaday : Because racecar!!

  • GBiv78

    Surely adding aftermarket suspension to an already high performance car isn't likely to yield high degrees of variation to performance? So the test is basically as useless as the mods. It would be far more interesting to see the differences possible with upgrades to low performance cars. This is like if you were slaying weight loss products tested on ripped athletes

  • maverick warden
    maverick warden

    This testing only proves how great the suspension from BMW is. Get a regular daily driver and compare the stock suspension with upgraded coilovers. Pretty sure the difference will be more than a second.

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