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Heat Cycles:

Heat cycling, or scrubbing tires, is a very useful thing to know about. But it is not something that many people understand or use properly. A tire will perform differently when it is new, compared to how it will perform after it has been through a heat cycle. This is not necessarily a bad thing. In fact, in a lot of cases, it is a very good thing indeed. In the case of the R1's, a heat cycle will make the tire wear much longer, and be more consistent in its performance. By this I mean that the tire will not change as much during a race or practice session if it has been heat cycled. There will be a slight drop in performance during a session , (lose grip), with non-heat cycled tires though.

Let's look at what a heat cycle is, and what it does to the tire. We will concentrate on the tread compound, but there are similar benefits for the other compounds in the tire that actually hold everything together.

To understand what happens in a heat cycle, let's talk about the molecules that make up the compound. For those of you who don't remember your high school chemistry classes, the molecules that make up polymers are long chains of atoms. To kind of visualize this, think of a bunch of rubber bands. Imagine that they have all been cut with a pair of scissors so that they are not closed loops anymore. Now throw a bunch of them into a box and shake it up. Those represent the polymer molecules.

In addition to being highly intermingled, these molecules are connected, (or attracted), to each other by a variety of chemical networks. For simplicity, we will refer to all of these networks as chemical bonds. These bonds, (or attractions), are what we are concerned with here. During the manufacturing process, these bonds form in a more or less disorganized way. Some of the bonds are very short and strong. Some of them are very long and weak. The rest of them vary between the two.

Now, when you take that tire and run it, things start to happen. The molecules get stretched and compressed. This first causes the weaker bonds that connect these molecules to break. When the bonds break, heat is generated. As the heat builds and the flexing continues, more bonds break, more heat is generated, stronger bonds break, more heat is generated, and so on... Remember that these bonds are what connect the molecules to each other. They give the compound its strength. When this strength is reduced, the compound can't grip the road surface as well. It rubs off instead of

holding together. The result is less grip, more slip on the road surface, more heat generated, and more tread wear. You can see that it can become a self perpetuating kind of thing. How fast this all occurs determines how fast the tires "Go Off".

So then, what happens in a heat cycle that can improve this pretty bleak situation? Well, actually, the situation described above is the first step in the heat cycle process. You want to break all of those "uneven" bonds. Because what happens next is where the real magic of alchemy comes into play. After these bonds have broken, and this heat has been generated, and the tires are finally allowed to be set aside and relax, the bonds tend to REFORM! But now they reform in a much more uniform manner! This means that they are more consistent in strength. Therefore, the compound becomes more resistant to losing its strength the next time the tires are run. That doesn't mean that you can't make the tires give up anymore. If you exceed the limits of the compound, (both mechanical and thermal), the bonds will still break. But they will be more resistant to it because they are working together now as equals (in parallel), instead of individually (in series). And, given the time to relax again, they will reform again in the same uniform manner.

Here is the most important thing to learn, and remember about this process. These bonds MUST be given ENOUGH TIME to do their magical reformation. In the case of the R1, the tires must be allowed relax for an absolute minimum of 24 hrs after that initial "break in". I will sometimes tell people to wait up to 48 hrs to be sure. But we really haven't seen any additional advantage to waiting any longer than that. If you don't give the tires enough time to reform those bonds though, then you are going out on tires with a weakened compound and their performance will show it. Understanding how this works, and how to use it to your advantage, is important to getting the most from your tires.

Let's talk now about the number of heat cycles you can expect out of a tire. I've heard people talk about Brand-X, or Brand-Y, or Brand-Z tires only being good for X number of heat cycles. We really have not seen this with the Comp T/A R1. You should be able to expect the same performance level from the tire after 20 heat cycles as you get after 1, (assuming of course that tread wear isn't an issue). Additional heat cycles beyond the first don't make the tire "harder". The tire can and will change over time just due to "aging". But that is due to other influences like ultraviolet light, ozone, etc. And that time period, with proper care, should be at least a couple of years.

So, to recap, heat cycling will help improve the consistency and longevity of your R1's. The first heat cycle is the most critical. Subsequent heat cycles do not cause any detriment to the performance of the tire. It is still possible to overheat heat cycled tires. But, assuming you don't do any other permanent damage to them, give them the minimum of 24 hrs. to relax afterwards and they should be fine for later use.

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rustang: Vt. näiteks http://www.toyo.com.au/tech_info15.html

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kronja:
natuke guugeldasin ja väga kindlat arvamust ei suutnud endale tekitada; kuidas kohalikud võidusõidumeistrid küsimusse suhtuvad?

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peep: Kui R1 puhul on kuumatsüklist kasu, siis ilmselt ka 888 puhul. See vahe ei ole ehk nii tunnetatav ega oluline meie ürituse raames aga samas, kuna kord rehv kuumaks sõita ja siis 24 h. seista lasta pole eriti keeruline, siis mina küll kavatsen seda teha.

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Jesper: Minuteada on Šveits ikka mingil poolkõval viisil euroliidu liige, nii et tolli maksma ei pea.

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que: Kusjuures ma olen ka varem aru saanud, et rehivmüüjate marginaal on eesti väga bro.

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Raceboy: Leidsin ühe rehvimüüja Saksamaalt, võibolla on kuskilt läbi käinud see link, aga enivei: http://www.reifendirekt.de/

Slikke müügis ei näinud, küll aga väga heade hindadega tänavarehve kõikvõimalikes ja võimatutes mõõtudes.

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