What size sidewall should I choose on a tire, if I jump up to 18" wheels? I imagine we should try to stay as close to OEM wheel/tire diameter as possible. I dropped from a stock 50 series to a 40 when I ran 17" rims. Should I drop to a 30 series then, or will a 35 be sufficient with 18s? I would rather not bang up my new rims with a 30 or smaller rubber band tire on our shitty Pennsylvania roads.
Thanks

 

Being that sidewall is a ratio it really depends on the width of tire you run. My 285/30/18 sidewall is 3.36 in and 245/35/18 is 3.37 in and 245/40/18 is 3.85 in, which rubs in the front of my stock suspension FD. Go to 1010tires.com it's helpful to see what's what.

 

Wow! Sweet website. Never been to that site before. Has a ton of info and specs. Aswered all of my questions.

Looks like 245/35/18 tires for me. Only throws the sppedometer off by .2 @ 60mph

Thanks a ton. Adding that site to my favorites.

 

How wide are the rims? You're going to be better off with 255/35-18 sized tires on most 18 inch street rims around 9 inches wide, the 245/35 has a very skinny sidewall.

 

They are 8.5" wide. With an offset of +38, if that matters.

I will probably do some drag racing this year so I'm not sure if I should go with the wider tires in the front. I have some M/T on stock rims for the rear.

The tires I was considering for the 18 x 8.5 rims are 245/35/18

Not sure which are stickier for autoX but was looking at either;
Kumho Ecsta XS or the Continental ExtremeContact DW.
Or maybe another suggestion in the same $ballpark

I only bring the car out maybe a dozen times/year. So I only care abouy dry traction.

Suggestions?
Thanks

 

I think you're on the right track, the Kumho XS are very grippy in the dry, just be careful if caught in heavy rain.

 

Shouldn't be an issue. Doesn't leave the garage unless 70 degrees and sunny.
The Continental seem to be getting decent reviews and only 21 lbs. Any thoughts?

 

Wow, that's crazy light. I'm biased against Conti's from the past decade of their sub-par tires, but these may be worth a shot. Let us know what you decide

 

Hmm? Never really heard anything negetive about Continental myself. Actually I thought they were the tire of choice for the Germans. BMW, Mercedes, etc.. I could be wrong about that though.
Anyway, I put a set on my Subaru SVX for the horrible winters we've been getting in PA and they were fantastic. On an AWD car they kept the tires from spinning much and seemed to get pretty good traction.
I realize a sticky, summer, high performance, tire is a completely different animal but so far I've had good luck witht the brand.