I know this must have been debated: whether to use a 225/45 front or to squeeze a 245/40 on the same 7" wide rim. The 225 is specified (for the RE71R) for a 7 to 8;5" rim, not much different from the stock 215/45 which is rated for a 7" to 8" wheel. However, the 245/40 is rated for an 8" to 9.5" wheel; going to 7" seems like quite a squeeze. The 245/45, 1" taller, is rated for a 7.5" to 9" wheel. The extra cross section height seems to allow it to be pinched more.

Unfortunately I haven't figured out any search criteria to figure this out. If you know what the threads are, know the correct search criteria, or would like to share your recommendation, you help is appreciated.

Sidebar: I went to order 225/255 RE71Rs today but was told the 4/30 shipment was delayed to a now projected 5/23. So there is some time to get this figured out since I can still change the order.

 

https://www.s2ki.com/s2000/topic/111...d/page__st__25

being discussed here as well.

 

I feel like I'm missing something. I've heard people argue for and against both the 225 and 245 for various reasons, but does no one run the 235?

 

Different tires are going to react differently to pinching. Some will be faster than their smaller width counterpart, some will not. It also comes down to feel. Drivers that are not able to feel the limit as well as others may desire the more "appropriately sized" tire so that the breakaway and slip angle feedback is more precise.

I ran 245/255 Z1 SS on my CR and it was very fast. A bar setting change, mild shock change and tire pressure tuning was all that I needed to restore a great balance to the car.

In my opinion, you won't be making a bad decision regardless of what size tire you choose in the range of 225 to 245 for the front. One will be faster than the other. Which one? Nobody knows for sure until you test it. But if I was a betting man, I would probably pick the wider tire.

 

^^ and he would know.

 

That was the tread that I based going forward with a 225/255 order. However, in that same thread someone added at the end that they are running 255 square on stock rims. So...it in the end it just leaves the issue hanging.

It is the height of the tire. The 215 and 225 are 45 aspect ratio with and are 24.7" and 25" tall. The 245 and 255 are 40 aspect ratio and also 24.7" and 25" tall respectively. The 235 only comes in a 45 aspect ratio and is 25.4" tall, raising the front 2/10ths of an inch. more than the 225 and and nearly 4/10ths more than the 245. If the car could be lowered (not in the stock class) some of that could be mitigated, but there would still be a fender clearance problem.

 

I run ZII SS in a 235/40 (yes they do come with 40 aspect ratio) on the front and 255/40 on back. with the OZ wheels, I am a bit gun shy to go to 245s, especially on the ZII with the wider tread dimension. Might consider the 245s on stones though.

 

You would have to make a choice...there is no 235/40 on the RE71Rs. On the V2SS they are interesting since they lower the car a bit without adversely affecting the suspension geometry. The Rival S folks are going to have similar limits: only 225/45, 245/40, and 255/40 sizes.

 

Being new to the s2k, I just bought some 225/255 RS3s to upsize slightly and getting an alignment to go with it. I have a stock front bar and don't plan to spend $700 on an aftermarket bar this year so I stayed away from 245/255.

From the previous threads I have read, if you go 245/255 you need an aftermarket bar to balance the car, but an experienced s2k driver will be more competitive with the wider tire.

If you are still getting your feet wet with the car you will likely have an easier time learning limits with the narrower front tire. If money and skill are not considerations I would run 245/255.

 

I also run 235/40 ZII*'s and love them. If that isn't a common size then it makes more sense, but I ran 235/40/17 on my last car for several years and assumed it was more readily available.