Diabolical RX8

Ok I really dont feel like reading all of that, so I am just going to post about something I did read on this thread.

225/45/18 are 101mm tall. 245/40/18 are 98mm tall. Discount Tire installed my 245/40/18's on the stock rims and said my speedometer might be off by 1mph at the most. Other than that everything should be fine.

In my honest opinion 245/40/18's have tremendous grip. I would suggest trying out 235/40/18's on the front and 245 or possibly 255 on the rear. The main reason I said trying a smaller width on the front is because I got understeer on places I usually had oversteer on.

It all comes down to your choice.

BlueEyes

Having less width up front (less grip) would increase understeer.

Diabolical RX8

It seems as if 245 was to wide for the front. Atleast for my car it does.

BlueEyes

In what way was it too wide?

It rubbed? too much grip?

Razz1

I use 245 with no problem. Mike has 19" wheels.

Many other people with 19" are running 245 or 255's I have seen 265 and 275 on stock rims, but i wouldn't go there. To me handling is better than looks.

eclps0

I have a 8.5 inch rims i need new tires should i go with 245/40/18 or for more expensive tires go with 255/35/18

I auto cross and drive very hard all the time

Razz1

Go with what ever is cheaper as you are going to wear your tires out fast eclspo.

PUR NRG

Not quite. He's offhandedly suggesting a 265 tire on an 8.5" wide wheel. For street use that's considered unsafe. It's one thing to do something dangerous yourself, it's another to tell someone else to try it.
I believe Hoosier race slicks have much stiffer sidewalls compared to street tires. As such I don't think it's valid to compare tire sizes that way.
That all depends on your budget. 245 is recommended size for 8.5" wheels, 255 is the max safe size. I have RT-615 255s on 8.5" wheels right now. You have to decide if the extra tire cost is worth the 0.2" extra tire width.
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APPLEBEES GIFT CARDS

brtzrx8

Will using the stock tires (225/45/18) on a 18 x 8.5 rim be too small. Also will it be ok if I have 225/45/18s up front and 245/40/18s in the rear, on a set fo 18 x 8.5 rims?

Thanks in advance...

Brett