Tire Decision

I autocross a 99 Miata Base regularly in C-stock. I run the Hankook R-comps Autocross tread. While cleaning up the rims (Carbotech brakes sure do create a lot of dust) I noticed that one of the tires is just starting to show cord. I was hoping to last the rest of the season on these and buy a new set over the winter break. 3 more autocrosses this season. Given up going for 1st in class but have 2nd nailed. Again, 2 years in a row. But back to the issue. I have 3 worn Kumho V710's that I kept, corded one. Now the choice is to mount 2 of the V710s and run 2 Kumho's and 2 Hankook's for the rest of the season, naturally matching on axle - front/rear. Most likely the 'kooks on the front and Kuhmo's on the rear. Or bite it and buy 4 new Hankooks. Might not run the R-comps at the last race because even here in Alabama it does get cold in early December and I've driven or rather skated on R-comps in the cold before. Scary. So the last race would most likely be on Azenis. I have 3 sets of rims. Enkei with the R-comps mounted, stock hollow alloys with Azenis mounted and NA daisies with Ziex 512's mounted for DD use.

Now arguments either way please. Next autocross is Oct 30 so have to have the decision complete before that.

Thanks

I'd love to help you with your dilemma, but your 7 tires cost more than my entire race car (and it's a Porsche!!!), so I have no idea what to do.

Do you have 2nd locked down? if so just throw hankooks and kumhos on there. thats only for two of the races anyway right? get through the season then get new tires for the new year. since nats is passed I see no reason to invest in new tires for two or three more autocrosses this year. keep in mind though that you could buy new tires now and have the NEW scrubbed off in the next two races thus leaving them very sticky for the first of the season next year. food for thought. good luck with your decision.

From my experience, put the stickier tires ( I assume the 710's) on the rear (stickier tires up front = donut machine)

The "kooks" are just as bad as R comps in the cold, I think worse, and they take longer to heat up

Yeah, second locked down. I was concerned about mixing the different traits of 710's and C71 "kooks". Actually the Hankooks are the stickier tire but was thinking 710's in the rear myself. But you did bring up a point I didn't consider, that of stickier up front = spin. Which is why I asked. Well aware of R comps in the cold, learned the hard way. But it is a 2 driver car which helps immensly for tire heat up. Daughter co-drives. I have thought about getting new and scrubbing them in but was hoping for a sale over the winter on Hankooks. Ever the GRM thinker .

Javelin, the car runs 14" rims, tire are more affordable at that size. The 710's came on the used set of 4 Enkei rims I bought for the price of one new and the tires were half worn then. And I got the Hankooks on sale. Spread out over a 18 month time frame, not much impact on wallet. Used Miata stuff is affordable, which is one of the main reasons why I stick to the Miata for autocross.

The real problem with using different compounds (especially in the late season cold) is that they will react to heat differently, so as the tires heat up they will be changing behavior in different ways at either end of the car. This is not going to lead to a car that is easy to drive fast.

I say mix 'em, put the less grippy tires on the back, and practice your drifting... er, I mean, car control skills. Especially since it won't affect season results. One of the most entertaining fun runs I've ever had was in an E30 325i with test fitted R-compounds on the front and all-seasons on the back. I could hang the back out as far as I wanted and know for sure that the front would do whatever I wanted it to do to recover, whenever I finally got around to feeling like it.

mix'em and go. Buy new tires in the spring and scrub'em in at an empty parking lot. Maybe do a little empty lot practice with your mix'n'match before the next event.