Jim Michaels

I've been using the cold natured 18" Michelin Cups for autocross and track this year. I drive on them to and from events, and the Cups work very well in that role. I also like them on track. Do the Yoko A048s work any better than the Cups for autocross (i.e., provide grip quicker)? I know they are noisy, so I'll turn up the radio while traveling to events. How well do 048s work at the track? Thanks.

intense_tracer

I'm curious about this as well. I'm getting ready to get a set of 19s MPSC (235F, 305R) for my 997 mainly for autocross but also a few DEs. My other choice was to go with 18s and get either the A048s or Toyo RA1s. How do all 3 of these compare? No one at my local autocross runs the A048s, but several run the RA1s and like them because they heat up faster than the MPSCs. My main concern is that the MPSC does not heat up in time to really make them worth it for the Autocross? Please advise.

I'm burning through my street tires (19s) fast, so need to pull the trigger ASAP! Thanks.

cgomez

MPSC provide more grip than both 048s and RA1s, but they need to build heat to do that. Therefore they are a terrible autocross tire.

The grip of the RA1s is almos the same as the 048s but they are far more consistent during a track session than the 048 that have a very narrow operating band (temp) and you might have to "cool" them (slow down) a bit to get them back to 100%.

None of them are great AutoX tires. For autoX nothing is better than Kuhmos or Hoosiers. (that's probably why nobody that's a serious Autoxer runs any of those). If you have to have one of these three for triple use (AutoX, drive to and back, Track) I would go for the RA1s.

Jim Michaels

My only experience with RA1s was on my RSA with 17" tires. They were quite slippery at autocross too, although I liked them for track (where they were also a little slow to heat up) and driving to and from events. Maybe the RA1s needed more scrubbing and wear, as the Cups are not quite as slippery at autocross now as they were earlier in the season. I liked the Kumho VictoRacers on the 17s, as they could fulfill all the functions. But the Kumho VRs don't come in 18s, and the V710s don't come in the exactly correct sizes. I'd like to avoid hauling wheels/tires on a tire trailer and switching them at events, so I may be stuck.

intense_tracer

Thanks for the quick response.

Looks like the RA1s have good sizes for the 997s too with 245F and 305R in 18s in proper diameters.

Our local autocross gives us 1 warm up lap and 3 or 4 timed laps as well. Usually, each lap is 30-60 seconds in time, unlike the SCCA events. Is this enough time to reach operating temp for the last 2 laps for these R compounds? If it does, then maybe I might give the MPSC 19s a try.

Jim Michaels

You don't have much choice of R-compound tires in the 19" sizes. R-compound tires will not get hot enough during autocross runs to provide their optimum grip, although they may provide slightly better grip during the last two runs compared to the first two, if you don't have to wait long in line between runs. Kumho V710s and Hoosier autocross compounds will provide good grip very quickly, however. They are just not tires one would want to drive to and from events on. Taking your car out on the road for a brief drive just before you run may help a little. Warm ambient temperature will also help a little. I know several autocrossers that have "co-drivers" who do all their runs first to warm up the tires and brakes for the number 1 driver. Ironically, the V710 and Hoosier drivers often cool their tires down with water between runs, while I'm wishing I had a hair dryer to warm mine up. Apparently, it's SCCA legal to cool down tires artificially, but not to warm them up.