(I posted this thread on the driving technique forum, but I figured it would be better to ask this kind of question here.)
I'm running the Dunlop SP Super Sport race tires now, but I have never push them when cold. The other day I was out testing my new alignment setting by RRE, and took a sharp turn pretty fast (the tires were still cold). The rear steps out with no warning (almost like driving on a wet surface), but I was able to corrected it. So, my question is, do R-compound tires have no grip when they are not up to temp?

 

Yes you need to build up a little heat in them before they offer all they have.

 

An obvious question should be, what's this new alignment?

 

Frankly, I'm a little surprised that someone running R-compounds wouldn't know that you need to get some heat into them before they grip. Is this your first time running R-comps?

You'll need to take it easy for a lap or two before they really start to work. Until then, they will grip worse than clapped out all-seasons. Also, when the ambient temp drops significantly, you may never be able to get enough heat into them to really work at all. Further, as the tires heat cycle, they will eventually lose grip even though the tread may look brand-new. This is why running R-compounds on the street makes no sense at all.

Emre

 

Not all R compounds suffer from heat-cycle death. In particular, Toyo RA1s never seem to "go off" due to heat cycling. They just run faster and faster as the tread wears down, right up until you wear through to the cords.

As for the Dunlop SP Super Sport Race tires, here's a good review:

http://forums.bimmerforums.com/forum...d.php?t=256400

Reading onto the second page (post #27), the author states that the "tires are holding up very well" after "quite a lot of track time" and that he has "decided to run them on my street wheels"... Also, the tires "perform so well cold that it makes me not want to take them off after track days."

Plus, Dunlop's own press release calls the tires "non-competition" tires and certainly implies that they are appropriate for street use, except in conditions where hydroplaning is possible.



Based on that description of the Dunlops, I would wonder if the original poster's problem with the rear end being loose could have been a function of the alignment (which was a new setting) or of the tire pressures not being appropriate for the tires. Just a thought...