Any Autocrossers here?

[mrmatto]

More tread and contact patch -- should have better cornering traction and less heat soak. At first blush, 245/40 seems like it would be too pinched and wouldn't have good steering response. But I've recently read from some GS people who are having good results with that setup at nationals, so maybe it's fine with that tire. A tire with softer sidewalls? Not so much.

I'm actually currently debating between 235/45 and 245/40 myself. Seems like a personal preference thing. Some people are OK with a pinched tire, and some people don't like the way it feels.

 

[mk8gti907]

Yeah, I do like the steering response with the 225/45. Just trying to get an advantage over the competition for 2025

 

[mrmatto]

Yeah, I do like the steering response with the 225/45. Just trying to get an advantage over the competition for 2025

In the 225 width, are you finding that the tires overheat at any point? Are they getting greasy before you finish your runs?

Generally speaking, more tread will last a little longer before getting greasy, but they'll also heat up more slowly. Do you feel like you are ready for your best runs in the front half, or the back half of the heat?

 

[mk8gti907]

I only noticed them get greasy at School our region put on, but our runs were going so fast that there was hardly any cooldown periods. I feel like last season my best runs were on the back half of the heat. We had a guy with a big head in a WRX competing in my class, so I may or may not have sandbagged to throw him off a little

 

[mrmatto]

I mean, you won't know until you do it. But if you look at what's being run at nationals for GTIs in GS, it's heavily RE71RS in 245/40/17. And they usually only get a few runs. That's probably enough evidence you need that the setup is good. You'll probably lose some steering feel but clearly the experienced drivers are finding the extra traction is worth it. Especially when competing against Civic Si drivers that can run 245 or 255 width.

 

[mk8gti907]

Definitely. I may just try that size and adjust tire pressures accordingly. I was just shopping on costco for the tires and 225/45 and 245/40 are only $4 difference.

 

[GTIfan99]

another question, tire size. We've ran 225/45/17 RE71RS the past two seasons. Would there be any benefit to running 235/45 or 245/40? Rims are 17x7.5 Sparco Asetto Gara.

I ran 245 40 17 on 17 x 7.5 with my mk7.5's when I ran GS. Probably a little beefy, but worked well with two drivers.

I feel very under tired at 235 35 19 with RE71RS's right now.

 

[mk8gti907]

I ran 245 40 17 on 17 x 7.5 with my mk7.5's when I ran GS. Probably a little beefy, but worked well with two drivers.

I feel very under tired at 235 35 19 with RE71RS's right now.

What kind of tire pressures did you run with the 245/40?

 

[GTIfan99]

What kind of tire pressures did you run with the 245/40?

Low grip old asphalt, 34 to 35 front. Grippy asphalt 35 to 36 front.

To get max neg camber in front, loosen all front suspension bolts, have some one use a 2 x 4 to pull the wheel to full neg camber, hold, then tighten. You'll get .1 extra negative camber for an hours work.

I ran .10 toe out front, zero toe rear, -1.8 camber rear. That was with 26mm RSB. It was dialed.

 

[mk8gti907]

Low grip old asphalt, 34 to 35 front. Grippy asphalt 35 to 36 front.

To get max neg camber in front, loosen all front suspension bolts, have some one use a 2 x 4 to pull the wheel to full neg camber, hold, then tighten. You'll get .1 extra negative camber for an hours work.

I ran .10 toe out front, zero toe rear, -1.8 camber rear. That was with 26mm RSB. It was dialed.

i'll have to do that when I swap tires in the spring. Should I do this before my alignment? I've got these specs saved for when I make an appointment.