I'd say there is no general answer to your question. There are so many varibles involved including but not limited to,,,,,,,, ruber compound, manufacturer, ambient temperature, asphalt temperature, tire pressure, among others. What really heats the tire up is acceleration and braking. Cruising will warm the tire and the faster you go the warmer the tire becomes. However, the tire really never gets hot on the streets like it does on the track with excessive acceleration and hard braking. If I'm not using tire warmers I usually wait until the forth lap before I really reach max velosity. First lap, hard on the straight and gentle in the corners. Second hard on the straight with a bit more agression on the brakes and curves, third lap is about 80%. Then it's balls to the wall kaos for the remainder of the session. It's winter time and I'd be just a bit more cautious with tires. They just won't perform as well in cold weather as warm or hot weather. More caution at night when the pavement cools than during the day when it's warmer? Good judgment and common sense is what counts! Have fun, be cautious!
