Aside from looks, are there any pro's/con's to one vs the other? I want to run a tire as close to 26" as possible, so will one out perform the other in autocross, drag or track?

Thanks,
Anthony

 

For auto-x, 18's have a better tire size selection. 17's have 275 and 295, but both are a touch tall. 285x18 are a pretty good height gearing-wise and the 295s are about the same width just a taller tire (24.9" vs 25.3").

Why do you want a 26" tire?

 

Wanted to try out a 26" for a little diff gearing. Maybe I'll just stick with a 25".

 

in autox it depends on what class your in. if in stock or STU then 17's are optimal, its said the 40's are faster than the 45's. but thats a lot smaller than your 26" ur looking for. if in SM then yes the 18's have a better tire selection for size.
i guess it depends on what your trying to do. 1 might not be good in another. ie u dont want 18's for drag, rotational mass, easier to spin something with a smaller diameter than a larger. if ur trying to do higher gearing, 17's with taller tires can be used.
the weight is a big factor that the 17's will have an advantage as well as a 40 series tire. which is smaller :-/

 

I run 17s due to overall savings. While 18s have a much wider selection for tires, 17s cost far less, usually 2-300 dollars for a set of 4 tires. I'm perfectly happy running 255s on a 9.5 inch wheel, and dont feel I need any additional traction with the level of driving I'm doing now.