Hardheadmandca

I posted this in the Mechanics section and haven't gotten much play, so I thought I'd try here.

I seem to get a lot of flats - particularly on the rear tire. I run good tires. I was using Ultra Gatorskins, and now Michelin Krylion Carbon - these with Mr. Tuffy liners. Still, I get flats. These are put on Neuvation M 28 Aero wheels.

I just went out to my van to get my bike out for my lunch time ride, and the back tire was flat again. It was fine when I put it into the van yesterday after my lunch time ride.

My bike tends to stay in my van. I live in Fresno, CA. It is now 97 degrees outside - probably higher in the van.

Is the heat causing these flats, or weakening the tubes?

Should I bring my bike into the office with me every morning?

One of my employees, a soccer player, says she can't leave a soccer ball in her car because the heat will expand the air and will damage it.

This possibility never occurred to me.

Snuffleupagus

If your tires are inflated to right at max PSI, I could see it being a problem. If you deflate the tires though, it'd remove the issue. Just pump them up and go.

curiouskid55

Uh, no.

Snuffleupagus

Sure about that?

Say he had his tires pumped to 120psi.

The tubes themselves may only be rated as far as 120psi. Going from say 20c to 60c inside of a hot car could cause a more than 10 percent increase in pressure...

asgelle

Except max pressure is 50% of pull-off pressure.

Snuffleupagus

That's assuming a 'perfect world'

Perhaps the tires or tubes are wearing/worn out, or already very slightly damaged.

biker128pedal

13.6% assuming constant volume.

johnny99

Very unlikely. I would believe the rubber melting theory before I would believe that the air pressure changed enough to explode the tube.

rob999

My bike is often in my car all day in DC heat.
I let air out of the tires, 'cause I was worried about blowing a tube as the air in the tire expands...

I never had a tire flat on me before I did this or sense...but I definitely had 'full' tires become pretty low by the end of the day and since I was going to have to pull out the pump any way I just let some air out in the AM. Better safe than sorry....

CastIron

I'd look three places,myself:

1) at the rim itself. Is there a small bur of metal in there somewhere? Perhaps a spoke head?
2) Tire mounting technique. If you're ham fisted like me, it's easy to boof.
3) take off the tubes that are flatting and inflate them under water to find the holes. You need to really study where it's going flat to discern why.

To experiment with the exploding tire theory:
Take a wheel and pump it up to 20psi over max. Set it indoors (say a cool dark closet) for 24 hours. Then move the wheel to your van parked in the sun for many, many hours. I doubt you're cooking the tire off, but this should provide a reasonable answer.

barba

Charles' Law is the one at play here. I think that your tires are fine in the car. I find it hard to believe that the change in temperature could bring the pressure up more than a few PSI. Even if it did manage to raise the PSI, the evidence would be that the tire was blown of the rim, not a simple flat. Are you checking carefully that there is no debris embedded in the tire when you change the tube?

vantassell

It seems more likely you have a slow leak. Are you changing out your tubes when you get a flat? or just patching up the hole?

Also, if you're getting a lot of flats, check your rim tape and the inside of your tire. There's probably something stuck in your tire the keeps causing flats, or you're not patching up the holes properly. I swap out my tubes every flat. I only patch if I don't have a spare tube available.

Hardheadmandca

I always use a new tube, never a patch - it's just not worth it to me. I do check for embedded materials in the tires. I have checked for spurs and not found any. The spokes are recessed and the rim tape is in good shape.

Right before my first century, a week and a half ago, I had these Michelins put on by my LBS while they were doing a pre-ride tune up.

This was a small puncture. I found a small thin piece of flat white plastic near where the puncture was, sitting on the rim tape. I have removed it, and will assume that it is the culprit, for now.

Thank you all for your help. I am still suspicious of the heat build -up in the car hurting the tubes, but there seems to me no physical evidence of that here, now that I have been able to examine the tube.

genejockey 

Really, what biker128pedal said is true. Even if it was 140 degrees in the van, the pressure would still be below 140 psi.

RTB

same thing happened to me show up to the club ride after work and the rear tire is flat. I had pumped it up to 110 psi that morning. I have seen a burst disk on a scuba cylinder let go after it had been sitting in the sun. I now only inflate my tire to 90 psi if they are going to sit in the car all day and have not had a flat since. If that is too low bring along your good pump.

Snicklefritz

I've seen tires explode in the wheel pit at races in the summertime - pumped up to the max psi then sit in the sun for 30-45 minutes...