I have a few winter "trackcrosses" coming up. Essentially higher speed autox.

I have a higher HP miata with some aero currently running a RS4 in 245/40/15.

For an event with temps in the 40s/50 would a undersized 205/50/15 all season perform better then a cold RS4 in a 245?

 

I ran some 245 RS3's on the street, in the cold a few years ago, and vowed NEVER to do that again! I would not even TRY to run something like that on a track - I like living.

 

You'll actually get heat in them on track. I ran R888s at a track day where the first session was 35* outside. Just took an extra lap to get up to temp. I've also ran R888s in the rain at a track day.

Use common sense and drive to the amount of grip you have available.

 

I drove my RS4's in literal snow due to getting caught in a freak early season storm a couple years back.... That was a butt puckering drive home I'll assure you..

That said, as z31 alluded to above. My thoughts are that as long as you can get heat into them on a dry track, you'll be fine. It may take you another lap or two to get there, but I wouldn't waste money trying to move to a different tire that you'll only use for a couple events then never want again. You wont be the only person making the same tire compromises. Know your traction limits and go enjoy IMO

 

Above 40 keep running whatever 200tw street tire you have, just know they might be real funky for a couple laps.

 

OP is talking about trackcross... think one-half of an out lap. He's not going to get any significant heat in them in the run.

I would recommend something like Conti ECS, but you're probably not going to find anything in a 245 except 200TW or lower.

 

yes, the RS4 is a great tire for many reasons but they like a bit of heat before they start hooking up a bit. I recently started trying RT660’s for cold weather and I’m extremely happy with them. You’ll read a lot of mixed reviews on this compound, so YMMV, but personally they reminded me of RE71R but better in every single way with a slight downgrade in wet performance. I set the same times on RT660 and A052 but the 660’s lasted over twice as long and cost less. Both A052 and RT660 were almost a second faster than RE71R at streets of willow. Again, this is for me, and I’m certainly not the best driver in the world.

 

Is your car modified or stock? I'm also looking at trying the RT660s next year, but in autox. Planning to run stock setup in Street class. I'm surprised the 660s lasted that much longer than the A052. Also, do you have video?

 

Modified, stock power but loads of grip and aero... Xidas, APR GTC300, huge splitter/air dam, etc, racepak usually logging a 1.6-1.7 G peak. I've got videos but none of them are uploaded to anything. Yeah, I never plan on getting A052's again. RT660's are a more driveable tire than A052's and for an amateur driver such as myself the confidence I gained with RT660's equalled out with the grip of the A052's. I have buddies that run A052's because they're much better drivers and need A052's to pull that last half a second, but they admittedly trash the tires after only one HPDE track day.