THSCC Forums

So it's almost time to nab some wheels and tires for C Street this season.

The plan was to just pickup a set of cheap stock wheels and run RS3v2's (215's) and toss on a Strano bar and call it a day. However, I've got my eye on a set of 15# Koseis and fresh 235/40 ZII's but am not sure if this is just too much tire for a 7" rim.

Any thoughts?

235s seem like more width than needed. That said, a lot of people run seemingly wide street tires on OE rims in BS S2000s (245/255 on 7.5 and 8.5" wheels) and feel like there is negligible downside. (Edit: this opinion may in part be due to the camber friendly suspension of the S2000 vs the FRS, depending on how much static neg camber you can get.) The Dunlops have a stiff sidewall as well, so maybe that helps.

Shawn or Scott (or Steve Duckworth in CCR) likely know what works, though.

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Steve Carter
1972 Datsun 240Z-- resto pics at http://picasaweb.google.com/srcartermd
2007 GPW Honda S2000-- STR 86

Oh wow the AP2 front wheel is 7-1/2 not 7. Hmmm.. I don't know why I thought it was 7" because the 235 ZI's I had mounted on mine looked pretty balloon-like.

I haven't seen pics from the seller yet so maybe that will shed some light.

Thanks for the response Steve and maybe the stiff sidewall makes it work.

As your competitor I think you should go for it

I tried some 225 K1's on my BRZ and didn't really care for it. I ended up with 215 Rivals and they seemed a lot faster. Of course that is also comparing K1's to Rivals so completely apples to oranges. I think Duckworth was running 205 Hankook's at the Jimmy V but dont' quote me on that.

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OK so I'm back in. Now which tire should I buy??

That's because I was wrong. 7" front wheel is correct. Hey, I run STR and haven't had OE wheels out of their storage bag in 3 years...memory is failing!

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Steve Carter
1972 Datsun 240Z-- resto pics at http://picasaweb.google.com/srcartermd
2007 GPW Honda S2000-- STR 86

Hahaaa no worries Steve.

Shawn, I'm not sure what K1s are. Do you mean Z1's?

Duckworth was running RS3 215's (stock size) and they seemed to get the job done but from what I understand you can't run wide on those because the softer sidewall. My set on the Focus felt great in a 245 on a 8" stock rim, so that makes me want to stick with Hankooks.

Yeah Z1's

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OK so I'm back in. Now which tire should I buy??

Coooool. That's what I figured but Kosei K1's popped in my mind for some strange reason.

Matt, you’re another welcomed addition to CS, otherwise known as Shawn Wipple’s kingdom. Last year our record was 21 competitors at Piedmont. I’ve been running 225/ 45/17 on 7” rims for a long time and like this combo. I did not like the Rivals, maybe that was because they have soft sidewalls. The ZII’s star spec’s on the Miata now are pretty good. Matt, if you have time this year, teach me how to drive.

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Mike Miller
AutoX VP 2016/2017
Just a C Stock Miata DD
Mazda Speed 3 Family Car
Corvette Z06 Toy

Thanks Mike and I'm excited about C Street, even though I still keep calling it 'stock'.

I have a feeling I'll be chasing you guys unless I can (hopefully) figure out the rwd thing again. With the popularity of the NC's and BRZ/FRSes lately, I'd say C Street is a healthy class and the NCAC should be a good turnout.

Good to hear about your 225's too and had no idea the sidewalls were so different than the Hankooks. Strano and a few others were telling me that 235/40 on a ZII is a good combo since they don't mind being squeezed onto the rim, so we'll see. Here are a few shots and they look good for ~30 run tires I guess.

are those fronts? If so, that's impressive how the wear triangles show no change.

If Strano says they will work, I'd go with it. He's pretty good.

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Steve Carter
1972 Datsun 240Z-- resto pics at http://picasaweb.google.com/srcartermd
2007 GPW Honda S2000-- STR 86

FWIW, Chris Fenter and Chris Harvey ran 235 ZIIs on their CS Miata last year.

Stuff like that is good to hear. My ZI's on my front 7" S2000 wheels were a little too wide but I can't recall if they were 45 aspect ratio, which would make sense. This is sort of running on the assumption that the tread/contact surface were the roughly the same between the ZI's & II's.

I think I'll pick them up. Anyone driving up to Baltimore soon by chance?

I've run 235/40/17's Z1 Star Spec's on my Miata in the past. Eric, I believe that you drove the car with that combination. For autoX, I thought that they were ok to good. My car is a daily driver as well as an autox car. I don't know if it was the weight or the distortion of the tire, but the larger tire didn't feel as good to me in every day driving as the 225's. I know that the MX5 Cup cars run 225/45/17's on 7 inch rims. There might be a reason or it might just be in the rule book. The 235's definitely fit on the NC Miata, but they may work better on a wider rim. I'm assuming that you will have a similar experience on the BRZ. The Miata has very soft springs and may be more sensitive to tire weight than your FRS. I tend to drive better when the car feels good. It's something to do with confidence.

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Mike Miller
AutoX VP 2016/2017
Just a C Stock Miata DD
Mazda Speed 3 Family Car
Corvette Z06 Toy

Funny you mention that because I realize that I put too much tire on the S2000's stock wheels running in STR and never felt totally comfortable in the car. The Civic and the Focus were the two cars that felt the most 'planted' through all kinds and speeds of transitions. Strange how that works out sometimes.