pros/cons 13" wheels

[oasis]

I was looking at options in the 4x130 bolt pattern and I saw 13" wheels that were 7" wide for SCCA racing. So my wondering made me do some further wondering -- what advantages do 13" wheels provide? Do racers want an overall smaller diameter for some reason, or do they want larger sidewalls for some reason?

[spannermanager]

Originally Posted by oasis

I was looking at options in the 4x130 bolt pattern and I saw 13" wheels that were 7" wide for SCCA racing. So my wondering made me do some further wondering -- what advantages do 13" wheels provide? Do racers want an overall smaller diameter for some reason, or do they want larger sidewalls for some reason?

They are a VERY viable proposition in my book, a lot depends on your agenda with the car, and its mostly 'fashion' that wheels are ever larger, but remember modern cars where designed for bigger wheels, ours were designed for 15" wheels and present problems trying to run much over this dia'. especialy as we try to lower them, i cant think of a better way to lower a high cog car than 13s, without major geometry problems, they are a popular choice in circuit racing, with a huge range of compounds and constructions, not to mention constant r&d and the latest Kevlar lightweight carcases.
theory says traction goes down with 13", but it only needs different thinking to recover it, gearing may need rethinking, but for hillclimbs or autocross events, i know where i would be, they wont go on a ball joint beam with drop spindles without some work with offsets , but i know they go over stock calipers because ive done it. why not go for it and start a new trend..

[KaferChris]

13x7/8's are probably the most common race rim in the world - just about everyone in a 4 cylinder at every oval track in America runs them. I raced in one class that allowed 13x10's...Usually tire heights in slicks are 21-23".

Here's a 'Ghia on 13's:


My old 'mini super' or 'pro-four' Type III rear drums and 13x10's: