Why Modifying Your Suspension Often Isn't Worth It (Road Cars) 

I need a comprehensive white-board explanation on how that hat stayed on your head.

A wise man suggested Upgrades in this order: tires, then the driver then the suspension.

Tire Rack probably did that study to show that tires are a better performance upgrade than an fully modded suspension. I'm surprised Jason didn't mention that a set of better tires could bring much more than a 1% increase. We all know how Jason loves tires.

BMW 3-series already has a pretty amazing suspension from factory, so I can see how aftermarket upgrades would have less of an impact on performance. I would like to see the tests done on an economy car.

Spot on, however the singular “flaw” in the logic of the Tire Rack test is the vehicle tested was a BMW 3-Series, which has one of the best factory-tuned suspensions and chassis available. Hard to improve on that with just bolt-ons. It would be more helpful if Tire Rack repeated the test with a common mainstream car like an Accord, etc.

To be honest, I wanna see them try that with a worse car. BMW already makes premium & luxury cars with performance in mind. Let me see how it improves a civic’s performance if you swap out the stock parts.

Interesting study by Tire Rack, yet what they really showed was how well tuned the stock suspension is on the BMW 3 series.

I value how the car feels. The grip maybe be them same but the confidence and feeling of control through corners of a car with body roll vs no body roll makes a big difference.

Jasons wife tells him she loves him. He lokks confused and asks; "But by HOW MUCH, in numbers?". Ah yes, the engineering brain!

I did just sway bars on my NB Miata and I think that was the perfect suspension mod for it. Doesn't really make the car any stiffer, but just dials back the body roll and makes it a little more responsive to changes in direction.

It is certainly worth noting that not all manufacturers tune their stock suspensions as well as BMW

I'm always impressed at Jason's flow and composure while driving, not seeming to have notes nearby (he could somewhere off-camera) or having someone in-car assisting, etc. Really impressive! And always great content :)

I think Sabine Schmitz showed how the best upgrade to performance on modern vehicles is upgrading the driver when she nearly broke 10 minutes on the Nurburgring - in a delivery van. Most people that do these upgrades never do anything that warrants them.

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.

Next "should you" vid: Big brake upgrade!

I did mine for the looks mostly. In this test, they started with a very high baseline. These changes on a carolla might give more drastic results.

I can confirm. I pushed my old 97 miata at max speed through a "course" with just good track tires, then tested with the tires and aggressive suspension. Lateral grip (speed possible through sweepers) was the same. The huge difference was in transferring weight and changing direction. Hands down in favor of suspension upgrade Edit: also, once you break past the point of grip, stiffer suspension will make it much more predictable giving you a better chance to correct small mistakes

The true purpose of all performance upgrades is so that they can go to Cars and Coffee and say "Look at the performance upgrades I've installed."

It's almost like the engineers who designed the car in the beginning knew what they were doing

Engineering Explained : Why Modifiying Your Suspension Often Isn't Worth It Fitment Industries : 😑

5th option: coilover+sway bar+geometry correction caster,bumpsteer bush kit

No one is gonna run the stop watch when im on the street, and when my brain gets impaled by my spine every time i hit a pebble, i feel like a racing driver... And thats worth all the money to me

They also tested this on a bmw, bmw suspension is designed to be comfortable yes but also sporty. They should’ve used some kind of economy car and upgraded the suspension, there would be a much bigger difference because the suspension wouldn’t be designed for sportiness

A lot of oem suspension on newer cars these days are designed with pretty decent handling even in suvs and are also decently comfortable at the same time. Go back 15-20 years and those suspension modifications will make a much bigger difference especially in something like an early 2000s Buick that would just sway lean and bounce several times over any sort of surface.

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 !

One major thing to take in to consideration is the age of the car. If they ran those tests on a mid 90’s car, as opposed to a modern 3-series, modern aftermarket suspension components will make much more of a difference compared to the 30 year old OEM components (which could also be well worn)

Suspension: As soft as possible, as hard as necessary.

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. :)

A lot of car mods are about what the driver feels and thinks, even if the change doesn't result in mo' powuh or herspers. It is better to feel faster than to be faster, right? :)

I am 100% behind keeping the stock suspension on a car. Every road vehicle has a purpose. The biggest improvement I had in grip and handling was when I replaced my stock wheels and tires with lighter and stickier ones. Great video!

Be interesting to see if those numbers hold on a car not as well tuned for handling as a new ish BMW. I'd suspect the delta would be larger

“Good suspension should soothe your brow, not attack it with a pair of scissors.” - Jeremy Clarkson

Most people that do changes to the vehicle... are replacing old components... not new stuff so any change is generally going to make it feel better.

Me rocking adjustable coilovers with polly bushings "I'ma pretend I didn't see that"

Is this a Miata in S2000 yellow? 🤭

Upgraded Shocks are usually done as necessary with lowering springs, because the stocks will usually wear out much faster if lowered. And lowering is often done for cosmetic reasons.

Tyre wear is my biggest reason for making changes. On track with standard suspension geometry, you absolutely tear through the shoulders of tyres. But most OE setups don't have sufficient camber adjustment or roll resistance to avoid this. This puts us in the hand of aftermarket changes.

In the case of BMWs being tested, I can imagine minimal performance gains with aftermarket suspensions. But BMW has always been a performance oriented brand, and the 3-series in almost all flavors is usually the handling benchmark. Now if we were to get comparisons for a usual econobox with OE suspension and then upgrades, I think it’s safe to say that the margins in handling performance would be huge, and worth the money / feel. I’d like to see Tire Rack take a base Toyota Camry and perform the same test, so that majority of the folks who’s aren’t buying luxury BMWs for their performance needs, can see what sort of performance gains can be achieved. Awesome video btw Jason, everyone needed to hear this !

You uploaded 3 minutes ago and you already have 3 dislikes, who the hell dislikes a video without even watching it?

Good points, glad you mentioned tire wear. My stock M2 was shredding the outside of the front tires on the track even though it handled fine IMO. I had to install camber plates and dial in more camber so the tires would last a full weekend. I hadn't planned on modifying this car but this was a necessary change. (Afterwards though, I could get through traffic circles quite a bit faster!)

Loved the video. I think most people do it for the lowered look overall things. But yes some for feel and performance as well. I know I’m gonna change my suspension mostly to lower my car and close up the wheel well gaps. But honestly would be nice to see if someone else has more data on this subject. But either way always enjoy your videos and enjoy learning more about cars🤓

Those yellow Bilstein shocks look good on your Mazda.

Good content. For people bashing the current MX-5 body role , the suspension is designed to cope with rough American back roads.

Your argument is very valid with new stock sports/sporty cars. The point you miss is that most people who modify their cars are driving older cars(with failing stock suspensions) or entry level/economy cars. This is where aftermarket suspensions turns peoples rides from just a means of transportation to something they enjoy driving. If you have ever driven a stock older Honda Civic vs the same Honda Civic with a good aftermarket suspension, they are both still very underpowered, but the aftermarket one handles like a race car, so much so that, testing will show a insane amount of improvement in all performance categories.

I placed an order yesterday for a set of Coilovers. I do not think I am going to regret the purchase. I do think they can make a really big difference on say, my Miata NB2.

I remember a video by a german RU-vidr at KW. Their Expert said professional drivers won't get faster laptimes from performance suspensions, but the cars become more predictable making it easier for amateurs to improve their laptimes and feeling for the car. Also modern high performance suspensions apparently are surprisingly comfortable - which checks out with the contents of this video.

Suspension can be a huge supporting mod that is good to do before adding more power. You don't want to learn that you need coilovers while spinning out on turn 3

I’m test driving a 2016 Miata club tonight. You helped me make my mind up

BMWs already are pretty tuned for performance from the factory. Did tire rack do any testing on cars that from the factory are not so tuned from the factory?

Well tuned suspension will stiffer and more comfortable at the same time. Key is high speed damping vs lowspeed damping

One thing you didn't point out is old cars. If you have an Na miata a suspension upgrade makes sense because of how far the technology has come since that car was made + how old the old suspension is getting.

If you want a noticeable performance upgrade, just get some summer tires and call it a day.

The 6 dislikes are the slammed bois

I can imagine road cars suspension is setup to keep the tyres as cool as possible, more tyre heat means more wasted energy. I can also imagine there's particular scenarios where a stiffer suspension could destabilise the car going over rough roads

Putting tein coilovers in my Honda Fit daily made it just feel more fun to drive as well as a little more comfortable (I went with the softest option they make). I honestly did it to have like a finger when gap tho😂 yes I am fixing my roll center before anyone starts yelling at me😂

I would love to see the same tests on some cars like a Toyota Corolla Apr something like that. BMW spends money to have more performance in the suspension, it would be cool to see if a more "basic" car would have greater gains.

But I want them low lows!

The way the car looks (much better a little bit lower) is important too

Miss my ND Miata. Favorite driving car I’ve owned. Just sooo much fun.

2014 VW GLI (stage 1 tune) - use General Gmax tires, upgraded stock shocks with Bilstein B4 (10% stiffer), OEM mounts, getting 034 Motorsport sway bar. Probably the best I can do and maintain comfort.

Damn, I just dropped big money on Coilovers for my 1990 Miata...lol

Also have a 2016 ND Miata Club w/ Brembo/BBS package just like yours, which came with a "jingly-jangly" Bilstein damper setup and soft sway bars. Swapped it out with a Flyin' Miata stage 2 suspension kit with better-balanced damping-profile Koni shocks, lowering springs, and stiffer sway bars (along with 15 mm spacers on all 4 wheels from Goodwin Racing). Now, it handles like a BRZ and looks amazing. The spacers are safe and don't suffer from the problems detailed in your video on spacers. Would do it again, no questions asked. There's a lot to be said for a suspension setup that isn't easily upset, yet still allows the driver to transfer weight with throttle and trail braking to control the vehicle dynamics for better turn in, drive out of corners, etc., and is also comfortable as a daily driver. This is how the car should've come from the factory. Absolutely worth it. I hear the 2019+ ND2 Club suspension was reworked to fix the issues with the ND1 setup... proof that the engineers who design cars don't always get it right the first time.

As the owner of a BMW 328, if you are telling me that if I converted my suspension by putting as many M3 parts onto my car as I can manage to fit, control arms, subframe bushings, upgraded ball joints, tie rods, etc etc, in essence making it a virtual M3, that it isn't going to significantly change my handling, I am going to have a REALLY hard time believing that. I think we can agree that the handling between an M3 and a 328 is massively different, so even if I got my 328 to be like halfway between a 328 and an M3, I think it would totally be worth it. I can't afford to do that lol but if I could........I feel like Tire Rack is trying to get everyone that is thinking of doing suspension upgrades, to just buy some really expensive wheels and tires instead.

those back roads are gorgeous man

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

I feel attacked in my autocross/track ready Camry lol

That Miata would be an ideal candidate to experiment on. It starts soft and has many after-market options that are fairly reasonable.

I recommend a book called “how to make your car handle” by Fred Puhn... it’s an old book but a lot of stuff in it is still very relevant and there is some great advice in there regarding suspension tuning, modification, design and more! Solid book

I like a mild lowering spring with a firmer mono tube strut. Slammed with crazy camber is for looks and kills handling.

Love the Miata video style.

Ok, here's a comment. I have owned a 1996 Subaru Impreza GTTurbo/WRX. When I bought it it was 8 years old and leaning backwards. It was slightly terrifying to drive at speeds over 180 kph. The grip was phenomenal but the handling was terrible. So when I had the chance I changed the OE shocks and springs for coilovers with camberplates and adjustable rideheight and dampening. I changed the rear swaybar for an slightly thicker one from a newer model (OE part). I got stiffer swaybar links and anti-lift bushings for the front trailing arms. I went to an alignment specialist and had it aligned the way I wanted it (stock was centerpoint, very floaty). (I never had strange tire wear, so I guess I had figured out a pretty good setup). It did pretty well on a track. With the rear swaybar and front camberplates set to max negative, it really dug the front end into the corners and you could just feel the rear start to slide. On the road, especially bumpy but also roads with more elevation differences, it was horrible. With only 5 cm or so of suspension travel, there wasn't much keeping the wheels on the road. On French back roads, I couldn't keep up with the locals in their little 1.4 Peugeots. It was also horrible for my back. There's more to suspension than just shocks and springs, wheel geometry has a huge part in he equation. If you haven't done so already, consider a video about that.

Definitely an awesome video! I’m surprised by how little “upgrading” suspension really upgrades the vehicle performance. I’m considering buying aftermarket suspension and want the lower ride height and spent countless hours trying to research the performance benefit. There seems to not be much of one but personalizing your own car to how you want it to feel/look should be worth your money after some research. I’m glad I watched this video, phenomenal job Jason!

I just took my first ride yesterday. My bike has been in the shop for a rebuild. Worth every penny I spent. It's riding better than new :)

And here I was thinking about getting Öhlins coilovers for my own Miata!

*visibly shaken up and jarred* "Yes, the coilover were totally worth it, nothing at all wrong with how it feels!" *door falls of Miata*

Enginerring Explained, I own a 2010 328i E92 is a coupe with sport package all around, and yes sports car it is but darn perfect for 11 years now and still the ultimate driving machine. And remember the type of steering you have also comes into play. Electric and hydraulic with the lower suspension by design is the nicest controlling car I have driven in 11 years. And ya it is a BMW

The best way to numerically determine the performance of the of the suspension will be to operate the vehicle on a Multi Post test rig. It'll determine literally every aspect of the car which can measure the damping of the shocks and the spring stuffness, to the stiffness of the chassis, suspension mountings, tyre sidewall stiffness, damper frequency, sprung and unsprung mass, sprung mass CG position, natural frequency of the car/ suspension, damping ratio, and many more! Thats the definitive way to see what's better rather than subjective tests on track

A BMW M3 is an interesting choice, well set up to begin with. I would be interested to see if they got the same results on something like a Volvo 240 wagon from the 80s.

My experience is consistent with these results at my local track. I wouldn’t change it back though. I love the look and handling of my 350Z so much more now. I warned my daughter that when she inherits it to take things easy as it’s now ‘quite lively’. 🤣🤣❤️🚙

It’s not often worth it. I fitted A Bilstein suspension on a Volvo 850R and it didn’t suit the car. The ride quality felt like it’s was riding on boulders. Edit: best to get a car that has been designed for on the ground up with the correct settings.

Upgrading to a performance suspension kit on my daily driver I saw a measurable difference in my bank account.

One case where a suspension upgrade is almost necessary, is the tesla model 3. The KW V3 upgrade compared to the stock suspension is a difference like night and day. It rides more comfortable over bumps (finally absorbs them rather than passing them to the cabin) while providing a much stabler ride especially at higher speeds, under harsh braking and through corners!

It all depends on the platform. My car tended to understeer from factory, lowering springs, koni adjustable shocks and an upgraded front sway bar fixed it to be balanced.

I put Bilstein shocks on a Supra which greatly improved the handling and they were still good 150,000 miles later when I sold it. My current Tundra had a very skittish ride when new, improved again by Bilsteins. My E36 M3 also improved with Bilsteins and side plates on the RTABs. My partners E90 328i had miserable handling and steering. This required Lemforder control arms, strut bushings, sway bar links and Bilsteins to turn it into a crisp steering car with no wallow. None of these cost a fortune, but they were all worth while.

Meanwhile I'm looking at my Citroën which runs on some weird green balls :)

In my experience, as an engineer and as a pilot, this is just "part of the story". If you just want to improve performances of your road car on trackdays, it is possible to find much more than 1% performance in suspensions (but only if you can make the right choices! ). Spring stiffness as an absolute value should not in general be changing as it affects grip, UNLESS you are going for better tires, expecially if they are wide tires! Then you may need to improve stiffness, BUT you will pretty soon start to be limited by chassis torsional stiffness, you can improve it a little bit, but unless you go for a full cage, This will in the end set the "vehicle dynamics limit of the car" . 2nd: adjustable coilovers will give you the opportunity to set up the balance of the car. This also means that as a driver you have to understand which one is the fastest way to drive that specific car: I have been trying to reach a perfect neutral balance mid corner, until I found out that changing this would allow me to be much quicker. 3rd: high performance (and expensive) coilovers have typically a better high speed damping setup, which will allow you to drive much more aggressive on some curbs without loosing stability, and gaining lot of time there. This stuff really makes the difference, but it is really hard to measure as it depends on each particular racetrack, and requires an experienced driver that is able to get to the limit of the car very quickly.

I went through 2 sets of 3rd party absorbers+8springs to discover that while they were better handling in the corners, the ride comfort was just as bad if not worse and they handled unexpected bumps/ridges in the road completely unsatisfactorily.

This needs to be discussed and tested for vehicles that are driven off road....suv's, cuv's and pick up trucks i.e. lifted susp. and performance off road shocks.

I'm running H&R springs with Golf R dampers on my 08 TFSi Jetta. It's pretty much perfect for Aussie conditions. Spent the cash I saved on better tyres... that's where dollars spent really make a difference on the road.

“Comfort is the main point of concern, especially on a BMW.” I fear that is true these days. Oh, how the once mighty have fallen! I miss my 1990 325i coupe.

I’m made two very big improvements to my 1969 Corvette suspension in 1970. I replaced the original bias ply tires with new radials. And I replaced the original shocks with adjustable Koni shocks. Both were vast improvements. Of course now everybody knows about radial tires and probably don’t know anything about bias ply tires.

The coilover kit used in this test came out 18 years ago in 2003. The most recent review for it is from 2010 and Tire rack no longer carries any of these products that were used in this test. The test was carried out using a 2008 E92 328i so I'm sure there are better suspension kits available now compared to the Eibach stuff used in the test. Like dude, it's 13 years later since they did this test. You made it sound like this was some hot off the press new study.

Sometimes it doesn't matter if the car is any faster, but if it is more fun or feels more connected to the driving experience that is enough reason for many to modify their suspension.

I think part of the issue with the test you cited is in the fact they were testing BMWs. BMW suspension was it's main selling point really for the better part of three decades. When I get to that stage of my life where I can have a proper weekender, or have my "mid-life crisis" car, I wouldn't mind going back to maybe an E-46 or even an E-39 325. The handling and suspension on those things were just perfect straight out of the box. I wouldn't think about changing suspension on a BMW or Mercedes unless I had already done am awful lot of other work and the car was going on a track. Same can't really be said for many less European cars. Particularly if you're going to be doing up an old family car, which is popular here. Suspension in that case is second thing you need to look at after brakes. Then tires/,wheels, then exhaust, then engine/transmission.

I helped my son put on aftermarket Eibach springs and Bilstein shocks to upgrade his suspension over the stock B7 Audi A4 suspension and it was night and day in improved cornering feel and reduced body roll with little to no loss in daily driving comfort. I think it depends on what car you start with. It the case of the B7 A4 it was worth every penny and we intentionally tried to select components that would improve performance without compromising street-ability and ride comfort, so stay away from cheap coil overs.

What I think a lot of people don't seem to realize is that upgrading your suspension isn't necessarily for improving lateral grip per se, but improving the handling characteristics of the car, or "how" the car handles, and in some cases, the engineers do a really good job at setting the car up to "how" the car should ideally handle.

Eh, the stock 02 WRX has extremely soft and tall suspension. Certain cars will react better then others to suspension upgrades

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.

One suspension mod that can be worth it in a lot of cases is stiffening the rear sway bar on a FWD car. As he said, most factory suspension setups favor understeer, and stiffening the rear sway bar on a FWD car can help the car rotate more on low-speed corners (like at autocross).

You pretty much covered the gist of it, however in race applications you change camber and toe to get the maximum out of the car which you can only do when you upgrade your suspension. In road cars you do not want to do that because you will go through tires every other week. That being said in my older Colt which was a FWD car I changed the dampers to stiffer sport one's (not the springs) and added a small sway bar in the front and changed all the wheels and tyres from a 13" to a 15" lower profile, I also added two very small spoilers in the rear (mostly for aesthetics but in high speed - over 140kmh it would offer a little bit of extra grip in the rear and surprise surprise less drag due to the shape of the car - hatchback and extending the air vortices away from the rear body). The feel of the car and the performance increased dramatically, the car was indeed on rails, from very understeery it became almost completely neutral (apart from very low grip cases in oil+rain) much more direct with less body roll and overall increased my confidence tenfold (confidence is the real performance gain - i hate understeer). Yes the car became much more nervous and over potholes it would clank violently so it needed a good driver. In general I agree with you, suspension changes in most cases would ruin not only comfort but performance too if done incorrectly. As a rule of thumb I do not recommend such changes unless the driver knows exactly what he wants to achieve and even then DO NOT go over the top, make small incremental changes and see if it feels better. In racing 3 tenths of a second per lap is eternity in real world driving it's less than nothing.