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Discussion Starter #1
Can you guys give me a crash course about tire heat cycles and how it effects me, or riding on the street? What does it have to do with the life of a tire or a particular brand? Does this have anything to do with not leaning too far into any turns with cold tires in the morning? Thanks guys.
 
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Re: Someone teach a new guy about the whole "Heat Cycle" hype!! (galaxy)

For street riding on street tires, the reality is that heat cycles do not even come into play.


My understanding:
Each time a tire goes from cold to hot to cold, that is considered a heat cycle. On the track, each time a tire reaches the point where rubber 'balls up' and sheds, the tire actually leaches out chemicals from within. Track oriented tires have a limited heat cycle life just as they do a limited thread life. Too many heat cycles and the tire loses the very chemicals that give it that stickiness - they tend to turn a bit blue.

Using tire warmers between sessions can reduce the overall number of heat cycles a tire goes through so that you can better match the number of heat cycles to the threadlife of your tire. Some people replace their track tires based on a certain number of heat cycles OR certain level of threadwear "whichever comes first" approach....
 
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I'm no expert, but my understanding is that a heat cycle is when a tire goes from cold (room temperature) to hot and back to cold again.

Racing tires aren't made to go through very many of these heat cycles. Something about the rubber compounds in the carcass breaking down somewhat with each cycle. Street tires like sport touring tires, don't produce as much grip at high heat, but are made to survive many cycles between cold and hot (although I'd imagine getting them really hot like at a track would still wear them quick.)

DOT race tires are considered by some to be great for both street and track. I have little experience with these, but I did have some Dunlop 218s at one point that I hated on the street. I didn't ride hard enough to get enough heat into them on the street. So I actually thought they were kinda slippery and as they went through heat cycles I felt the condition got worse.
 
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Re: Someone teach a new guy about the whole "Heat Cycle" hype!! (hank)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hank »</TD></TR><TR><TD CLASS="quote">they tend to turn a bit blue....
</TD></TR></TABLE>

This is a myth. I’ve had race tires that had two heat cycles on them that have turned blue and have seen many more laps without any loss of grip.
 
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Re: Someone teach a new guy about the whole "Heat Cycle" hype!! (galaxy)

I think maybe the whole concept is a myth.
I can imagine chemical processes happening in the rubber as it changes temperature that would be different if the rubber were always at the same temperature, but it's also very possible to "cook" a tire by keeping it hot for too long without any gaps. There's definitely a finite amount of time the tire can last while hot, but whether there's any difference between getting that time continuously or in multiple periods, I don't know. I personally don't worry about it at all.

Also, blueing doesn't come from heat cycling, it seems to come from getting a tire hot and then letting it sit for a long time while in contact with air, especially cold air. My race tires regularly turn purplish-blue over the winter sitting in the garage, even if they've only seen one short heat cycle since they were new - and if I set one leaning against the wall, it will turn colors everywhere except in the area that's in contact with the wall. The discoloration is just at the surface, and goes away the next time I run them.
 
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This is funny...I can vouch for "blueing"...Right now,we have a taxi speed restriction on my airplane due to tire blueing. Engineering hasn't really gave us a good reason for the cause, just that speed in general and in turns too fast are aggrivating the problem. I've actually seen a couple, but it doesn't really jump out at you. Really dark bluish color (almost blends in with the black) forms where the edge of the sidewall and the tread meet, if you can picture the part that would get scuffed up in a fast turn. Seems to be a new issue so I don't know if it could have something to do with the compound they are re-capping them with or not??
 
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Re: (galaxy)

I have noticed that older tires on cars tend to dry out & crack. So could the blueing be due to some sort of carbon 'oxidation' from perhaps ozone or some other interaction?
 
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The blueing I spoke of really isn't effected by the age of the tire. Seems to be strictly a heat issue, but I'm sure it's closely related to material composition somehow cause like I said, it's a new issue on our tires.
 
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Re: Someone teach a new guy about the whole "Heat Cycle" hype!! (galaxy)

Nah, doesn't have anything to do with how far you lean on cold tires in the morn. Try not to do that anyway with any tire. Generally speaking most street riders needn't concern themselves with heat cycling. BUT, if you are into hardcore canyon stafing to the point of cheese grating your tires with little balls of rubber coming off then it may be a concern. Last fall I was following a local on his RSV Mille shod with Dunlop 208's at Deal's Gap when he lowsided. Perfect corner with runout for a crash, no injuries but broken sump. He'd been coming there for years on his trick 900SS Duc and had always ridden Michelins. He and his buds have been goin there for years staying for a week at a time. They'd already been there for days doing exteme high speed runs on local roads. The day before his crash he thought his tires were getting "greasier" at the end of their ride. That night he also thought the rubber was harder than should be. He hoped it would soften up the next day riding. It didn't and down he went. The tires had under 500 miles on them. Some think I corner pretty aggressively (and lord knows I try!) but I never cheese grated tires on the street till I rode Deal's! Midweek, morning, 85-90deg, little traffic, no 5-0. Corners so tight you can barely crane your neck far enough to see! Ya hoo! Absolutely fantastic! I've heard you've got the canyons in CA, how ya gonna ride em? Have fun, MH
 
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