Wheels, tires and ride comfort.
 

Hi guys! Frequent lurker, first time poster here! Currently drive a stock BRZ.

I was wondering this: How much does wheel weight and tire selection affect ride comfort?

I've been finding the ride in the BRZ a bit harsh over rough roads and highway expansion joints, with road imperfections sending vibrations through the car and highway expansion joints almost as if tossing or jolting the occupants. To be honest, the stock wheels don't bother me too much style-wise, but if dropping a couple pounds from each corner could remedy the harsh ride it would be something I'd consider. How much of the ride is in the tires? I'm still on the stock Primacies, and would be looking to swap to the Michelin PSS or a Potenza tire in 225/45 for more grip and a bit more sidewall.

Tires: considering Michelin PSS in 225 for the stockers or 17x8 wheels, but don't really like the rounded sidewall/balloon shape, or Potenza RE003 (closest thing on TireRack is probably the S04 Pole Positions), which have a much squarer profile that I like. I've also always run sticky Potenzas (RE11 on my RB3 Odyssey) so I'm a bit biased, but all of my previous cars have been more comfortable than the BRZ. Downside is that the Potenzas have stiffer sidewalls and weight more than the PSS.

Wheels: I was considering 17x8 RPF1s (15-ish lbs per corner). I'd have to think much harder about going even lighter as the TC105N and CE28N are in a completely different price range.

I get it, this car handles great and rides not so great, but it'd be nice if the ride was a bit more... German. Stiff is fine, but perhaps a little less harsh would definitely be appreciated. Thanks in advance!

If you're not concerned with the aesthetics of smaller wheels, 16's may be a way to get some additional ride comfort. More sidewall, less weight, means more compliance.

There's a ton of information in this thread: http://www.ft86club.com/forums/showthread.php?t=27023

I'm running 16's with snow tires on them (not representative of a performance tire, certainly, and the switch from stock wheels/tires has certainly taken the edge off harsh bumps. When I'm shopping for wheel's, I'll be seriously considering going with 16's.

I have MPSS 225/45/17 on stock wheels and I don't think it looks balloon-y.

http://imgur.com/bWIGwn6.jpg
http://imgur.com/RuzCaOE.jpg

Generally speaking, the higher the second number (stock is 215/45R17), the softer the ride. Downside is generally less responsive handling. If you went with a 16" wheel to something like a 205/55R16 then it would be softer ride. 245/40R17 which is what I run in non-winter months is slightly less soft than stock. Going with 245/35R18 would be even less soft.

Side note: I can't really notice the difference between lighter wheels and heavier wheels, but some people can.

Wheel weight doesn't really affect ride comfort. Tire selection does. Thicker sidewalls yield more comfortable rides at the expense of responsiveness.

On another note, I think 17x8 rpf1s are great wheels for the car. They aren't too wide so the car is still playful, yet they're very light.

Actually, that looks perfect. Fears quelled. Did the ride change at all?

Was hoping the drop in unsprung weight alone could improve ride quality, but it sounds like my mileage could vary...

Also if we're talking only about tires, in the same size, would I be gaining/losing anything in terms of ride harshness when comparing the stock Primacies/PSS/Potenza?

For reference, my BRZ has the stock Primacies but I daily on the Potenza RE-11.

I recently changed to RE002s (can't get RE003s yet here). The ride is noticeably worse over Primacys it has to be said, but it's all worth it when you come to a corner. So much better.

In theory the greater the ratio of sprung to unsprung weight the better the ride. So reducing wheel weight will be more comfortable.

I noticed I dropped about 3 MPGs. Road noise went up a tiny bit, but it wasn't bad. When I first got them, it felt like initial turn-in was a little less precise, but that might have been my imagination. Ride quality didn't seem to change.

Regardless, once I got them on the track, I was thoroughly pleased.

Well, primacies are of low rolling resistance. No wonder of economy drop installing grippier tires. Every tire is compromise of sorts with different sorted priorities. One just has to choose tires that fit best his individual priority set. :)

Hi,

I would like to know if your car is lowered? (does not seem to be in these photos)
Also, do you have spacers?

I plan to replace the OEM Michelin with 225/45/17 Michelin Pilot Sport 4S and I am afraid that the tires will rub in the rear wings.

I currently have 25mm spacers and a drop of about 1.25"
The 215/45/17 are relatively close to the wings.

I read that some people with 30mm spacers and stock tires/rims had some rubbing.
Adding 10mm tire width (5mm each side) may create the same issue?

Does anyone here drive with 225/45/17 tires, 25mm spacers and a drop of about 1.25 "?

Thank you for sharing your thoughts.


(PS: I have consulted several conversations on this forum. Thank you for all the information present.
It helped me a lot and keep helping me in my choices of modifications.) :thumbsup:

Honestly I don't remember, as that was 3 years ago. I think I was at stock height then, and no spacers.

Nowadays I use 225s on stock wheels with 15mm spacers all around, and with around a 1.25" drop. No rubbing issues at all, but I also have an aggressive track alignment.

Do you mind sharing the specs on your alignment? I'm hoping to change mine soon to -3.2 f and -2.6 rear.

I had 225/45-17 tires on stock 17x7 wheels for about a year. Switching from stock Bridgestone Turanza 215/45-17 tires to Yokohama Advan 225/45-17 tires made a big difference in comfort and grip. The sidewalls did not bulge out, fit was perfect and within specs. If you want more grip, comfort, stability, 225 was noticeably better for me. If you are more into drifting, 215 could be better.

Front: -3.4 camber, 0 toe, max caster (around 6.8)
Rear: -2.2 camber, 0.2 toe

Edit: I'm about to install some SPL FLCAs, which will let me play with the numbers a bit more. But those are the specs I've used for a couple years now.

Thanks!


SPL parts are nice! Are you max camber in the front now? Also, do our cars have OEM caster adj?


Thanks again!

No, could get a few more tenths in the front on my current setup, but I still daily the car and don't want to get *too* crazy. And no OEM caster adjustment. I'm using raceseng cascam plates.

Thanks! I figured as much about the caster adj.


I recently replaced a bunch of suspension parts... I look into how to add caster more.



I don't want to get Too Crazy either. It happens sometimes though.:thumbsup:

Thanks again!

any excessive wear due to running that much camber at highway speeds/straight line cruising?

Nope. Toe ruins tires more than camber, and I'm zeroed out in the front.

That's good to know! Thanks!


I was curious about -3 or more camber in the front...


I knew that -1.5 front and -2.2 rear didn't cause any uneven wear, as I have had those specs for 65,000 miles.


Thanks again!

Depends on where most of wear for one happens. If one does 5-10 or more trackdays per year, then camber of -3 is beneficial, as 4/5th of tire thread will be worn on track and if anything, they will wear more even and will last a bit longer.
If one never tracks, or at most 1-2 trackdays, then -3 might be excessive, and imho some -1.5 may be more reasonable.
If one does more then 10 trackdays, i doubt any tires will last longer then that anyway :)

I don't think that tracking the car has to do with the amount of camber being reasonable. If the tire wear is acceptable to the owner, then it is by definition "reasonable"

"reasonable" in my book - changes handling to wished, enhances grip, makes wear better. On all these accounts it's different for if car is daily driven vs tracked.

For example - when daily driving (within legal limits) car never sees such side-Gs for tires to flex enough to need lot of static camber to compensate, thus with less camber tire contact patch will be more even/better (for driving mostly straight, in turns taken at reasonable/legal speeds, or when there is lack of grip, eg. when wet/on ice/on snow), resulting better traction when accelerating, better stopping distances, better tire wear. Car also will tend less to "follow" longitudinal road grooves.

On track with high side-Gs you get more even contact patch and more grip with more camber to counter that tire sidewall flex. Faster laptimes, even "track" tire wear, not just chewed tire outer side with rest of tire still having loads of thread left. No "enthusiastic driving"/"fast canyon runs" on public roads will provide those loads, unless one goes at 2-3 times posted speed limits, endangers himself and others on road and such.

After i did my first 5 track days, i had worn around 3/4ths of total tire thread, even if total mileage on track was just small portion of daily driven mileage on public roads.

Due all that above is why i "link" advisable/"reasonable"/best chosen camber when doing alignment to amount car gets tracked. Most wear happens on track - choose more track oriented alignment. Never or rarely tracking and just ramping up tens of thousands miles on daily driven public roads? - car benefits more of daily driving alignment if you want to maximize setup.

Of course except wear/handling/performance there can be reasons such as some stance/camber "scene" thing, eg. "hella-camber", or if one chooses unreasonable wheel/tire choice (too wide and/or staggered), and needs that extra camber simply to not rub/clear fender arches & suspension bits. But such are minority, and i don't care much about such reasoning, as for me it's always function over form and i choose specific tires/wheels/alignment settings only for performance/handling/practical (eg. even wear thus money saving) reasons.

So many assumptions... If the word was "Optimal", I would agree with you.

Almost 40k miles on my street tires at -3F, -2R and the amount of camber wear is negligible.

Excessive toe usually wears down much more. Hence the reason many cars (including ours) have at very least toe adjustment stock. After all, toe = wheel preturned all the time to (toe-in, positive value) or from (toe-out, negative value) centerline, hence it drags tire slightly sideways, increasing wear, even when tracking straight.
Wrong camber for use provides extra wear less. It more affects unevenness of wear, "camber wear". If car tires won't wear much for eg. mentioned 40K miles, then lot of static negative camber won't add much "extra" wear, rather that same wear will be distributed more to tire inside then center/outside, due wheel always skewed a bit sideways. It will "increase" wear mostly in sense, that if one side of tire is down to tire cord, it makes little sense to keep using tire, even if other parts of tire still have lot of thread left, due wrong camber wear.