Dunlop Star spec Z1 as front Tire high speed "autocross" ?

[Schulmann]

I am tracking and riding on street a 2006 Coupe.

We have a very special race track here in Montreal. This is the Mirabel international airport. We ride this track in 3rd gear around 100mph. It is like a giant go-kart or Autocross track.

The concret is very very tough on the front tire. The grip on the concret is very high. The Michelin PS2 is the front is just "falling apart". I am loosing chunks ... I don't want to put -3 camber in the front ... I am just running -1.8.



I was thinking about running Dunlop star spec Z1 in the front 275/35/18. This tire has a good reputation for autocross on BMWs.

My rear is Michelin 345/30/19


I could also increase the tire size in the front but still the outside of the tire will "chunk" or the Viper will over steer. So the size 275 looks good, it gives a very good balance to the Viper.


Can we combine Dunlop with Michelin PS2 in the rear ? How would be the high speed stability at braking ?

 

[j-rho]

Wouldn't recommend mixed tires F/R, the balance of the car will be inconsistent as the tires move through their grip vs. temperature curves. Not to mention the differences in feel and response, etc.

Shaving a new street tire can actually decrease the probability of it chunking, due to reduced tread squirm. As such, it may actually increase tire life when used under severe circumstances as you plan.

Another tire you might want to consider is the Kumho XS. It is a street tire with performance similar to the Dunlop Star Spec, but comes in a rear size you can use in the Viper. I would recommend having them shaved to 4/32" to reduce the probability of chunking. You can order them shaved from the Tire Rack. If you're overheating the outside edge I would also recommend more negative camber in the front, -2.1 or 2.2 would help, and as long as your front toe setting is at or near zero, it shouldn't really hurt street wear.