Overheating tires

Hey guys,

I am having a graining issue running mg reds at my local track CHMS. A new set of tires are fast the first session (duh) but there is a huge fall off from that session to the very next. Even at starting at 7ish psi the tires seem to have nothing left even when I think I am gentle the first time out. I run an energy eclipse with a ka on it and run the standard run of the mill Douglas mags and wondering if anyone thinks running a low volume otk wheel or something of the sort would help. Any recommendations?

Thanks

Lower volume wheels might help but part of the problem is probably just the surface at CHMS. We’ve always found it to eat tires pretty quickly, as the surface is pretty old and abrasive.

The Monza and the final tunnel corner both are tire-killing corners too. Tire wear always looks atrocious at CHMS.

I thought you’d want much more pressure in MG Reds. When I’m low on pressure with any tire, I get lots of wear. How about going to as much as 12 cold?

You can even go higher than that. We race 18-20 in the cold evenings. I’ve heard even more at NCMP.

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I would definitely go up on air pressure. Last time I raced there I was at 8psi right rear, on MG Yellows in the shifter category for a 25 lap main in pretty warm weather. I would try starting at 10psi and see what that does for you. May even need to go up from there. The tires are never going to look good at that track.

Would higher pressures prolong the life of the tire?

Generally Higher pressures=more heat (which could lead to more wear, of course there are many other variables but in general higher pressure will raise tire temp). you get less surface area of the tire touching the track with higher pressure, will it really prolong tire life In my experience no, in fact I wouldn’t tune for tire life unless your just going out for fun/low on tires.

Someone feel free to contradict me but in my experience that’s what I’ve learned.

No, a higher pressure will typically reduce contact patch and overheat and grain tires quicker, as @SahibT noted.

@tjkoyen, just curious; is there any relationship between pressure and where heat is built in the tire?

For example, would lower pressures tend to generate more heat in the tire carcass (due to increased movement/twist/deflection), but less heat in the tire’s contact surface, and visa versa for higher pressures?

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Yeah that’s generally what I’ve always believed.

The guys at MG once told me the proper way to warm up the tires. They said big, sweeping high-load tire scrubbing is how you build core temp and quick sliding is how you build surface temp. The sliding flashes up the surface of the tire but doesn’t build any retained heat.

By that logic, a higher tire pressure will build more surface temp as it’a sliding across the surface more and the tire isn’t deforming. A lower pressure will not flash up as quickly on the surface.

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Cool, thanks for the info! :+1:

That makes sense. I guess the only way to prolong the life is not to run them :slightly_smiling_face:

I did hear that deflating the tires after a race day helps prolong life…

Also wrapping your tires!

Very cool to hear you share that. I had a very old-school mentor when I first started karting. He said scrubbing tires on the out lap “heated the wrong part of the tire”. So, instead of scrubbing tires on the out lap, I always lay back and then run the corners as hard (and safely) as I reasonably could. I felt it showed me level of grip i the cold tire too vs just wiggling the wheel back and forth. I always have done it this way because I didnt know any better or maybe out of habit now? Maybe I got lucky and mentor wasn’t as crazy as I thought…

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Are you serious? With cling film? Why would that be?

It’s pretty common to wrap tires between long periods of use. It helps keep them from being exposed to the elements and keeps the natural oils of the rubber from drying out.

Interesting tips. Thank you