Affect of wheel width and offset on stock suspension feel

[Ohio Enthusiast]

Originally Posted by Capt Spaulding

The steering will be marginally heavier, you should notice substantially less understeer and the maximum grip level will increase as well. It will feel more "serious" and less playful.

I'm pretty sure that's what I'm after as well. Still, I have some time to really get to know the car stock before I need to jump the gun on the wheels.

Originally Posted by RuyGuy2

I went down in rim size to a 16" and Up to a 225 tread width and 50 sidewall. I got used to the steering feel in the first 20 minutes not a huge change, to be honest I can't remember what it really changed in the steering feel on the car it was so small.

Cornering, braking, and acceleration all improved quite a bit.

That's really interesting! Could you give some more details on the setup (which wheels and their size and offset, which tires)? Also, did you go to this wheel/tire setup straight from the stock 17" Primacys or did you have other tires to compare with?

[scottbrz]

I'm basically in the same boat as you. I'd like to replace my stock wheels with some nice lightweight wheels. But, I don't want to mess with the stock feel too much. Also, the car in bone stock form is already fast enough to get me into trouble, so making it faster is not particularly important.

And, I have PP brakes, so that complicates things.

Every time I look, I keep coming back to RPF1 17x8 et45. Several sources say they fit the PP brakes. And the 3mm difference in offset should not be too significant. Tirerack specs seems to suggest you can stretch a 215 tire over them.

But, do the 17x7.5 et48 fit the PP brakes? I don't recall seeing any info suggesting they do. If they do though, they'd be the obvious choice for me.

[Ohio Enthusiast]

Originally Posted by scottbrz

And, I have PP brakes, so that complicates things.

Every time I look, I keep coming back to RPF1 17x8 et45. Several sources say they fit the PP brakes. And the 3mm difference in offset should not be too significant. Tirerack specs seems to suggest you can stretch a 215 tire over them.

But, do the 17x7.5 et48 fit the PP brakes? I don't recall seeing any info suggesting they do. If they do though, they'd be the obvious choice for me.

I don't have the PP, and I actually opted to buy a non-PP BRZ somewhat due to this reason - wheel selection is a challenge. According to our registry for PP fit (https://www.ft86club.com/forums/showthread.php?t=135328), 17x8 should fit the PP brakes, but there's no mention of 17x7.5. Since the 17x9 don't fit without spacers, I'd say it's not clear cut that the 17x7.5 will fit. I'd hazard a guess that due to the higher offset vs. the 17x8 you'd need spacers to fit 17x7.5, negating some of the benefit of keeping stock configuration.

On the other hand, if you don't want/need the 8 inch wide wheel, you could try the 17.7.5 and if they don't fit try some spacers. For most wheels that don't fit mild spacers seem to be enough.

Edit: actually, it might be that the narrower wheels will actually have better backspacing, so they might fit without spacers. This is especially appropriate for the RPF1 that are more convex in narrower widths (so the more concave 17x9 not fitting might actually be a good sign )

[RuyGuy2]

Originally Posted by Ohio Enthusiast

that's really interesting! Could you give some more details on the setup (which wheels and their size and offset, which tires)? Also, did you go to this wheel/tire setup straight from the stock 17" Primacys or did you have other tires to compare with?

The wheels are pressure cast sport edition P4, enkei makes an identical rim size and offset wheel. My wheels are 16/7 +35 I had factory wheels with the Michelin then some R3's, before I switched to these. I wanted a good all season tire with decent performance so I went with General Gmax AS-05. If you drive your car in the snow or bad weather this tire is flat out awesome. Performance on dry pavement for how I use the car is good enough and it's got good overall life.

[Ohio Enthusiast]

Originally Posted by RuyGuy2

The wheels are pressure cast sport edition P4, enkei makes an identical rim size and offset wheel. My wheels are 16/7 +35 I had factory wheels with the Michelin then some R3's, before I switched to these. I wanted a good all season tire with decent performance so I went with General Gmax AS-05.

Awesome, thanks for the info!

[scottbrz]

Originally Posted by Ohio Enthusiast

Edit: actually, it might be that the narrower wheels will actually have better backspacing, so they might fit without spacers. This is especially appropriate for the RPF1 that are more convex in narrower widths (so the more concave 17x9 not fitting might actually be a good sign )

After a bit more research, it appears the 17x7.5 RPF1s won't fit. So, 17x8 it is then.

I'm also considering the Continental ExtremeContact DWS 06 since they are 20lbs (same weight as the stock tires). I just have to wear out the Primacies first.

[Ohio Enthusiast]

I ended up getting the Enkei RPF1s in 17x7.5. I'm very happy with them - the stock Primacys look a tad stretched already on the 7.5, I doubt I would have liked them on 8 inch wide wheels. According to the Butt Dyno™ the car feels sprightlier in low gear acceleration (the Enkeis are about 5 lbs lighter per wheel).