Ride Quality, Handling on 17" vs 18"

[Spektyr]

Specifically asking those who've driven the Gen2 on both 17" wheels and 18" wheels, ideally with same/similar tires.

Is there a noticeable difference in ride quality, harshness, handling characteristics, etc, and if so how would you describe the difference? Which do you prefer and why?

Thanks in advance.

(I have 18" on mine and haven't been able to compare them to anything else, and I'm debating whether there's an advantage to having a second set of wheels/tires on 17".)

[Edkwok99]

I use 17 inch for track and oem is 18 inch for daily (same diameter). I definitely can feel more bumps and stiffness riding on the 18. Sometimes I feel like I want to throw up after meal on the 18. I am actually looking to get another set of 17 for daily driving. 18 is just not for me with the rubber band tire (215/40)

[gskv]

i've just ordered a set of RCE T0 and 16" OEM JDM wheels to combat the bumpiness and stiff suspension.

[Dake]

1st Gen here, but regardless it's all about that sidewall. The difference between a 40 mm and 45 mm sidewall is noticeable. So option C is go up a size on the sidewall for your 18".

[dragoontwo]

Originally Posted by Dake

1st Gen here, but regardless it's all about that sidewall. The difference between a 40 mm and 45 mm sidewall is noticeable. So option C is go up a size on the sidewall for your 18".

You do know that the 40 and 45 are not the height in mm right? You do know that it is a percentage of the tread width, right?

[Rustyoid]

I think overall weight makes more of a difference than an extra half inch of sidewall. The OEM 18s are relatively heavy, 23.x LBS if I remember correctly. Light wheels improve everything significantly

[SuperTom]

Originally Posted by dragoontwo

You do know that the 40 and 45 are not the height in mm right? You do know that it is a percentage of the tread width, right?

That plus you will throw off speedometer and slower acceleration with larger diameter tire.


Yep its all about the weight. Especially on the outside perimeter. On a 17 the weight of the barrel is pulled in closer.

[Dake]

Originally Posted by dragoontwo

You do know that the 40 and 45 are not the height in mm right? You do know that it is a percentage of the tread width, right?

You know... I don't think I did (or if I did it fell out). I just knew one was taller than the other and assumed!

That plus you will throw off speedometer and slower acceleration with larger diameter tire.

Anyway, this is true. Going from a 17" to an 18" while keeping the 45 sidewall will result in your speedo showing 3.5 mph slower than you're actually going, whereas dropping to a 40 sidewall on the 18 will only throw off the speedo by about 1 mph.

[Busybee]

Gen1: switched from 17 oem wheels with Michelin AS4 (215x45) to 18x7.5 STI (from 2018 ts) with Michelin PS4S (215x40).

Maybe it’s just me but there is nothing dramatic. First time using 18 on the brz and totally fine for the daily. Almost no difference on mileage and stiffness. Everything else is stock on the 2019 brz.


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[drivejumpfly]

How about tire wear on the 18s? Think you can hit 7,500 miles on them with moderate driving?

[Busybee]

If you asked me, just switched 10 days ago.


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[Racecomp Engineering]

The tire type itself makes the most difference IMO. More than weight and sidewall (within reason).

I always caution against ultra-light wheels if your roads are extra crap because wheels can and do bend.

- Andrew

[Spektyr]

I've got BFG Comp2 A/S on my 18" OEM wheels right now (waiting for the weather to warm up enough, consistently). The ride quality is "quite informative". You get the impression you know everything there is to know about the road surface, but it's not "was that a boy worm or a girl worm I just drove over?" Fillings don't rattle, but if you had a sore back before you get in you should probably take some Aleve ahead of time.

I'm okay with it the way it is. I also wouldn't mind taking some of the sharpness out of it as long as I don't lose much (or ideally any) of the handling quality.

I'm toying with the idea of getting a set of daily driving tires on 17" wheels and keeping the 18s for track use.

I realize that for the most part it's all about compromise - can't have everything. And the cost has to make sense.

[Yoniyama]

Originally Posted by Racecomp Engineering

The tire type itself makes the most difference IMO. More than weight and sidewall (within reason).

I always caution against ultra-light wheels if your roads are extra crap because wheels can and do bend.

- Andrew

My Enkei RPF-1 bent when going over a pot hole (at around 15mph).

Super-light cast wheel is more prone to bending, whereas super-light forged wheel is more prone to chipping and cracking.