as more and more people start with the track day craze they are asking about heat cycles on their tires. i have copied a few different paragraphs from different car/bike racing tech pages for people to look over and try and understand what is going on.
these are not my opinions, just what i found
Another good idea is to track is the number heat cycles your tires experience. Each time your tires get hot they release chemicals from deep within the rubber. As the chemicals are released the tires lose some of their grip. You can see tires that are hardly worn lose their grip due to heat cycles. Count the number of heat cycles that your tires go through and you may find a repeatable pattern that lets you know when to get that new set
Q:_ What is a heat cycle on racing tires? How does it affect the wear and grip of a tire?
A:_ A tire heat cycle is when a tire is brought up to operating temperature and run for some laps, then allowed to cool. Taking a tire through a heat cycle changes its chemistry. In most instances it stabilizes the tire compound by decreasing its heat generation. But that process also slightly increases the durometer hardness of the tire. So scrubbing the tires (one heat cycle run) will help the tires run a little cooler and wear slightly better.
Successive heat cycles will continue this curing process. Eventually the tires will not provide nearly enough grip because they have gotten too hard, but they will wear like iron. Each heat cycle cures the tire rubber more and makes in harder.
Keep good records on each of your tires so you know how much use – and how many heat cycles – each of your tires has.
Heat Cycles: Heating your tires for practice and then keeping the warmers on between practice sessions saves Heat Cycles (the # of times a tire gets hot and then cools) which age your tires (the tire goes "off" meaning the best grip is gone).
here is my 2c..... if the correct operating temp for your tire is 180' F (just a number i pulled out of my ass), and with a brand new tire it takes 2 laps to warm you tires up to operating temperature, then the next day ( i am spacing it out longer than a session) it may take 3 laps, then 4 laps etc.
at a certain temperature a tire's compounds have a chemical reaction which makes the tire sticky and gives it more grip, after each heat cycle the tire hardens and then it takes longer to get to that temperature.
each heat cycle hardens the tire (as explained before), if you cool the tire very slowly it is less likely to harden as much as if you pulled off the track, parked the bike on a stand and let the ambient temp cool the tires. this is why a lot of trackday riders/racers will put their tire warmers on but not plug them in, the insulated blanket will slow down the cooling effect.
chickenhawk tire warmers also have a low temp setting where you can almost have the warmers on the low setting all day.
of course if you live in Ariziona the 110'F air temp and 130'F track temp means you dont really need warmers