How important is tire width and sidewall size for autocross?

I jumped over 13s because I figured if he's going to lose the 14s, he should do better than going from the lowest to the second-lowest level of Tire Selection Hell

(and I was assuming he didn't want to change overall wheel diameter too much while running a lower-profile tire)

SVreX wrote: Why no love for 13's? I've run 13x8s on my '84 GTI with great success. Smaller diameter wheel means less rotational/ unsprung weight. Depending on tire choice, it can also mean smaller outside diameter, which can change your final drive ratio very positively on a low powered car. You can have a big contact patch, reasonable aspect ratio, AND improve the shift points. Can anyone tell me why everyone always jumps to the 15's and does not consider the 13's? I agree about the 14's.

I'd think about 13's but I can't run 8's in STS and I've done a 10.1" rotor and Griling 54 Caliper upgrade from a 16v Scirocco so I can't fit 13's. 14's are the smallest I can go.

GameboyRMH wrote: (and I was assuming he didn't want to change overall wheel diameter too much while running a lower-profile tire)

This too. I have a working oddometer that still says I have 77,000 miles on the car so I hate to throw that off! If that ever stops working on me then I'd think about a lower profile tire that wouldn't match the oddometer calibration.

Duke wrote: For me, 13s won't even begin to fit over my brakes.

Huh. They fit on my Miata wearing '97 brakes (minor grinding). They fit easily on my GTI.

In reply to Contradiction:

Ok. Fair enough.

SVreX wrote: Can anyone tell me why everyone always jumps to the 15's and does not consider the 13's? I agree about the 14's.

Because street tires.

ProDarwin wrote:

SVreX wrote: Can anyone tell me why everyone always jumps to the 15's and does not consider the 13's? I agree about the 14's.

Because street tires.

That's actually a pretty good answer.

I am generally only looking for odd wheel sizes/ unique aspect ratios, etc. for my race cars (which I don't generally drive on the street). I couldn't care less about that stuff on my my street drivers.

Therefore, 13's work for me (but might not for someone who cares about street tires on the same car).

SVreX wrote:

ProDarwin wrote:

SVreX wrote: Can anyone tell me why everyone always jumps to the 15's and does not consider the 13's? I agree about the 14's.

Because street tires.

That's actually a pretty good answer. I am generally only looking for odd wheel sizes/ unique aspect ratios, etc. for my race cars (which I don't generally drive on the street). I couldn't care less about that stuff on my my street drivers. Therefore, 13's work for me (but might not for someone who cares about street tires on the same car).

Yeah, if I cared less about the appearance and street driveability of this car I'd have "Berg Cup Kit" wheel flares like this and 13x8s in a heartbeat:

The car is just too original and clean to go that route though. Maybe someday I could see myself building another one in that fashion with a 1.8T motor swap to go along with it.

In reply to Contradiction:

I've got the Berg body kit AND the wheels, if you ever want to get serious.

SVreX wrote: In reply to Contradiction: I've got the Berg body kit AND the wheels, if you ever want to get serious.

Don't tempt me! Or at least let me find a good shell for it first!

I almost bought a stripped out track car MK1 that would have gotten that treatment but it was getting pretty tired and there were some structural rust issues that concerned me. I also felt like half the performance parts on it were worn enough to need replacement anyway.

I literally went home after looking at it a second time and loosely negotiated a price and I popped onto searchtempest.com and typed in "rabbit" hoping to find a clean southern shell to transfer parts to and mine popped up 2.5 hrs away in Chicago and in MUCH better shape. I bought it 3 days later.

Okay, a friend of mine has a set of 15x6.5 Jax Light wheels that were on another MK1 GTI and were good for fitment for him and I can get them for $250. These are 12.9 lbs. each so this is kind of a no brainer.

He was running 205/50/15 first gen Azenis on them before. The are shot so I'm going to replace them with ZII Star Specs.

On a 6.5" wheel is a 205 okay?

205 on a 6.5 might not be quite as stiff as on a 7" or a 195 on the 6.5, but the 205 on 6.5 will work fine and still get all the tread on the ground (and should still be within the manufacturer recommended width range).