Tire Rack Rocks!

[Mako Koiwai]

Ordered a set of heat cycled 710's yesterday at around 2 PM. Asked for regular ground shipping. The Tires arrived at our place in South Pasadena before noon today!!! ... shipped of course from their Las Vegas facility. Last time we had to wait while they heat cycled a set in Indiana.

[Steve Abbott]

I would ask around about getting them heat cycled. From my understanding it's a waste of money.

Steve A.

[Scott McHugh]

IMHO Not necessary to heat cycle them

[Mako Koiwai]

Not if you went to the Kumho Seminar that Brian Robertson organized a few years back. Obviously doesn't make a huge difference, but $60 extra when you're already spending over $1,300 is worth it to me ... considering what each lap costs in tires. One thing is clear ... you can't heat cycle tires yourself unless you have the discipline and extra tires and wheels to do two hot laps on the brand new tires, and then let the tires sit for 24 hours. You just can't get the tires hot enough any other way.

[Tom Berry]

I agree with Steve and Scott.

[Mako Koiwai]

Well in that case! ... the Kumho engineer gave a pretty good talk about Heat Cycling. On the other hand, I was watching a video on how tires are made, and what the engineer described seems to be what happens during manufacturing, so you would think that it's redundant to heat cycle?

[Aaron Goldsmith]

Data says the tires are always slower the second time you use them, I wouldn't heat cycle anything I was taking to a national event.

[Mako Koiwai]

This is in effect what the Kumho rep was saying ...

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.

[Mako Koiwai]

From Discount Tires (didn't Josh Sortor work for them?)

http://www.discounttiredirect.com/direc ... ycling.jsp

[Mako Koiwai]

Tire Rack's Tech Article on Heat Cycling:

http://www.tirerack.com/tires/tiretech/ ... ?techid=66

[Christine Grice]

from the Hoosier website:

A6 Autocross

For autocrossing, the A6 does not need the same break in procedure as the R6. The A6 needs a minimal scuff-in session before the first autocross run. This “session” can comprise of simply driving around the event site at minimal speeds on the A6 set of tires. By scrubbing off the newness of the tread (no or minimal shininess remaining) prior to your first competitive run, the A6 tires will be more consistent in handling, grip and responsiveness on the first run. If this is not completed, running on un-scuffed A6 tires on your first run may result in the tires not gripping properly, or feeling like they “skate” over the course surface. You are welcome to run 3 – 5 psi higher when scuffing in a new set of A6’s, but be sure to reset them to the correct operating pressures before your first autocross run. As you compile autocross runs on your new A6’s, they should become more consistent in run times.

https://www.hoosiertire.com/rrtire.htm" onclick="window.open(this.href);return false;

[Mako Koiwai]

The next paragraph:

"Cure" Time
After completing the initial run phase, the length of time the tire is allowed to set is possibly more important. The barest minimum for this process to be beneficial is 24 hours. (Not "the next day"). Any less than this is a waste of time. The best situation would allow a week before using the tire again.

Proper tire management is a difficult process. To accomplish this almost always requires a second set of wheels. The payoff is greatly increased competitive tire life.

... emphasis mine.

[Marshall Grice]

what you're posting links to is correct BUT your first autox is good enough to heat cycle them properly. unlike road racers we don't go out and beat on a tire for 20+ continuous minutes a session. so no need to have them pre heat cycled.

The truth is your kumho's will age-out before you wear them out. And with the hoosiers they're so slow by the time they get past 50 runs we get rid of them anyways regardless of how much tread is left. so again, don't pay extra money for heat cycling, you don't need it.

[Rad_ Delgado_]

Ordered a set of heat cycled 710's yesterday at around 2 PM. Asked for regular ground shipping. The Tires arrived at our place in South Pasadena before noon today!!! ... shipped of course from their Las Vegas facility. Last time we had to wait while they heat cycled a set in Indiana.

So you're paying extra to get less life of your autoX tires? TireRack and Kumho must be very happy.

[Bob Pl]

Skip paying for TR heat cycle (on 710's) and use the $$ to flip them one (or two) times. Disregard "this side out", and reverse direction of rotation each event.

If TR sold toasters they would want you to buy the extended warranty on them. They are, after all, in business.

Let's hope the current administration does not bail out any tire companies or we'll be competing on ultra high mileage, low rolling resistance stones (possibly made out of bamboo or some other pc material.)

Oops, wrong forum for that last sentence, disrgard.