General Cycling Discussion - Will my bike be safe from the heat ?

Heya'll... just finished building up my new Lemond bike, and was wondering... usually on Tuesdays and Thursdays I go on club rides after work... meaning I have to leave my bike in the back of the truck with a shell on it... it gets pretty hot in there, especially now, in the summer, the temps are in the mid 80's.... so my question is... is it safe to leave it in there ? will the heat do anything to the grease, and/or lube on the bike ? How about tires/tubes ?? I know that heat expands things, and I've had a spare car tire explode from being in the heat before (it had something wrong with the steel belt, but blew anyways)

Lemme know what you think.. I can always bring my bike into work in the nice A/C....

Thanks

Jeff

You shouldn't have any problem leaving your bike in the back of a truck. The oil and grease should handle much higher temperatures than what will be seen in the back of your truck. Similarly, the tires will be fine. Any increase in pressure due to a temperature rise is minor and can be neglected. You tires probably get hotter from riding on hot pavement.

Then again, your bike would enjoy the A/C.

Originally posted by supcom
You shouldn't have any problem leaving your bike in the back of a truck. The oil and grease should handle much higher temperatures than what will be seen in the back of your truck. Similarly, the tires will be fine. Any increase in pressure due to a temperature rise is minor and can be neglected. You tires probably get hotter from riding on hot pavement.

Then again, your bike would enjoy the A/C.

I've got to disagree with Supcom... I'd suggest deflating the tires unless you want to risk a blowout, the inconvenience of it, and the wasted $$$. I had a blowout last summer after a ride and my bike was just hanging in the garage... In Houston, that means the garage might have gotten above 110F. The inside of a vehicle is likely to be much hotter.

For the minute or two it takes to pump up your tire before the ride, it's worth it to inflate just before you take off.

I didn't notice where you're from - so if you're in Canada, forget I mentioned anything.

Originally posted by Trekaholic


I didn't notice where you're from - so if you're in Canada, forget I mentioned anything.

Let me add, that here in Toronto the temperature this week has been hovering around 31 degrees (88F) 2 weeks ago, we hit 100F, and at night it usually is around 77F. So it ain't that much cooler up here :crash:

Don't make me jealous. We are in the middle of winter down here and the daily temp struggles to 15ºC, fortunately that's as cold as it gets. 32ºC is my ideal temperature, especially for beer.:beer:

CHEERS.

Mark

Originally posted by AquariaGuy
Let me add, that here in Toronto the temperature this week has been hovering around 31 degrees (88F) 2 weeks ago, we hit 100F, and at night it usually is around 77F. So it ain't that much cooler up here :crash:

OK, AquariaGuy, I hereby bequeath to you the authority to deflate your tires. Just don't write back in the winter when it's gotten so cold they shatter going over blocks of ice or dead caribou.

:beer:

I'd take the bike inside just to keep it safe from the bike thieves. Sooner or later, someone will see it in the back of your truck and steal it. Don't let it out of your sight!

Originally posted by SipperPhoto
Heya'll... just finished building up my new Lemond bike, and was wondering... usually on Tuesdays and Thursdays I go on club rides after work... meaning I have to leave my bike in the back of the truck with a shell on it...

Lemme know what you think.. I can always bring my bike into work in the nice A/C....


if you can bring the bike inside, why not just do the smart thing and RIDE IT TO WORK on the days when you have "club rides."

Originally posted by slotibartfast
I'd take the bike inside just to keep it safe from the bike thieves. Sooner or later, someone will see it in the back of your truck and steal it. Don't let it out of your sight!

well i have a shell on the back of the truck.. adn it is locked up.. and I work in a safe neighborhood.. so i'm not too worried...

Jeff

Originally posted by OneTinSloth
if you can bring the bike inside, why not just do the smart thing and RIDE IT TO WORK on the days when you have "club rides."


hmmm if I didn;t live 30 miles from work with like 3, 10-12% hills each way, I probably would... it's a little tough to do 60 miles each day, and still have any energy to get things doen when I get home

Jeff

Originally posted by Trekaholic
OK, AquariaGuy, I hereby bequeath to you the authority to deflate your tires. Just don't write back in the winter when it's gotten so cold they shatter going over blocks of ice or dead caribou.

:beer:

Blocks of ice maybe... but caribou.. I don't know if we have much of that in metro.

Originally posted by Trekaholic
I'd suggest deflating the tires unless you want to risk a blowout, the inconvenience of it, and the wasted $$$.
Yep. I got two heat blow-outs on a bike carried in the back of a station wagon before I figured out the problem. Deflate your tires and throw your floor pump in the truck when you load your bike. It takes little time (and no money) to re-inflate tires.

Funny, we have been getting up to 115 F here and I haven't had a problem with my tires at 120 PSI. I guess there must be a lot of variables.

The safest thing to do is deflate the tires, especially in a camper shell......temps can easily reach 120+....no kidding. My tire once blew out simply by sitting out in the hot summer sun.
So where is this Thurs evening club ride? I do the Rose Bowl ride on Thurs evenings, but these guys are waaaaaaay to fast for me... I could use a change of scenery if reasonably close to where I live.

I live in Atlanta, GA, and ride my bike at lunch time daily, and put the bike in the back of my Explorer. I failed to deflate the tires, and had 2 blow outs, on 2 different days. The first time it was the front, the next day the rear. It was mid to upper 80's both days that the blow outs occured. I recommend to deflate the tires for sure. That is what I'm doing now.

Originally posted by George
The safest thing to do is deflate the tires, especially in a camper shell......temps can easily reach 120+....no kidding. My tire once blew out simply by sitting out in the hot summer sun.
So where is this Thurs evening club ride? I do the Rose Bowl ride on Thurs evenings, but these guys are waaaaaaay to fast for me... I could use a change of scenery if reasonably close to where I live.

Well if you are ever in the OC area... lemme know.. I ride with the OC Rebel Riders outta Irvine.. near the 5 fwy and Jeffrey Rd. They are more a social group that rides... usually rides are broken up into 2 or 3 groups... usually a faster group.. a medium group, ad a slow group.. i usually ride int he middle group... but I'm usually faster than most of them... but i'm not quite sure i'm ready for the fast group yet.. a few more rides...

check them out at www.ocrebels.com

I still think we need a SoCal Bikeforums meet :D

Jeff

Originally posted by WorldIRC
Blocks of ice maybe... but caribou.. I don't know if we have much of that in metro.

What the hell is a caribou? Is that like a Geo Metro or something?

According to my calculations, a tire inflated to 120 psi at normal room temperature of 25 deg C (298 K) will increase to about 130 psi at 50 deg C (323 K). So, if you inflate your tires at, or above the maximum or if your tires are not in good condition, you might consider deflating them slightly.

Originally posted by SipperPhoto
Well if you are ever in the OC area... lemme know.. I ride with the OC Rebel Riders outta Irvine.. near the 5 fwy and Jeffrey Rd. They are more a social group that rides... usually rides are broken up into 2 or 3 groups... usually a faster group.. a medium group, ad a slow group.. i usually ride int he middle group... but I'm usually faster than most of them... but i'm not quite sure i'm ready for the fast group yet.. a few more rides...

check them out at www.ocrebels.com

I still think we need a SoCal Bikeforums meet :D

Jeff

Thanks Jeff......Irvine is a bit too far for me. I live near downtown LA. I'll check out the link and keep those tires deflated a bit. Thanks! George

I would think that high temps would cause deterioration of the tire rubber, handlebar cork or gel tape, saddle leather or vinyl. I would not leave my helmet or cycling shoes in the closed up car for the same reasons. And if you use CO2 inflators, there's another problem. Take it inside if you can....

Originally posted by supcom
According to my calculations, a tire inflated to 120 psi at normal room temperature of 25 deg C (298 K) will increase to about 130 psi at 50 deg C (323 K). So, if you inflate your tires at, or above the maximum or if your tires are not in good condition, you might consider deflating them slightly.

Supcom has apparently nailed down the science behind this tire popping phenomenon.

It's been a while since I studied chemical engineering, but one equation I remember well was the Ideal Gas Law, which states that PV=nRT, where P=pressure, V=volume, n=number of moles of gas, R=gas constant, and T=Temperature, in degrees Kelvin.

Assuming for a tire that P, V, and R are all basically constant for a tire rated at 120 psi and inflated to that amount, then the equation balances by increases in n offsetting decreases in T... and vice versa.

With that thrilling stuff said, what may be at issue is not so much the absolute temperature, so much as the difference in temperature from when the tire was pumped up to 120 psi vs what it becomes inside a hot car, or in my case, inside a garage. In the situation where I pumped my tire up, I did so in the house, at, say 70F. As the tire's temperature rose more than 50F higher than that, the Pressure inside the tire had to increase beyond the tires rating plus whatever safety factor the good volks at Continental specified. Kaboom.

I suspect that if you leave your bike outside or in the garage all the time, and you're pumping it up to 120 psi when it's 90F outside, the differential in temperature may not be enough to blow the tire.

Now I've used 120psi in my example, but your results may differ. I'd guess this is never a problem for people riding mountain bikes with big gnarly tires that are generally inflated to lower pressures.

One thing I know for sure: I wish I'd seen the thing blow, because the hole was huge and ruined the tire.

When it gets hot here in Las Vegas Tourists always say it's a dry heat. Yea, so is fire.
At any rate, I've never had any heat issues with any of my bikes.

PV = nRT is the equation I would use for calculating tire pressure changes. However there are some assumptions that go along with it. (Your tire does change shape when it is inflated, so V isn't exactly constant) It's close enough for a rough estimate though, likely within the tolerance of your temperature measurement.

That being said car interiors can get up to between 150 and 160 F in some cases. So there is even more heat to worry about.

Your tires and tubes are made of a polymer. Most polymers don't exhibit sharp phase changes between rubber and melt. (like ice to water) Rubber properties vary as temperature varies. A good way to think about it is that a rubber is a melted solid that is held together by entangled molecules. As more heat is applied, melting does occur.

This transition zone between rubber and melt varies on a lot of things. I don't doubt for a second that the heat in the car expands the molecular structure and entanglements that keep your tire together. Thus your tube and tire are weakened, when combined with higher pressure....boom!

Can you keep a window in your rear compartment slightly opened? This would really help keep temp down.

Hope this helps, It should be mostly right, though my polymer knowledge is limited.
CranialCrusader

Everything on the bike should be just fine. I would highly reccomend deflating the tires. It is a little suprising to sit back on the bike after a long, hot day and have what sounds like a gun go off just below you.

Where are your priorities? Your Lemond will survive the heat just fine. If you're going to use the AC, reserve it for the beer, okay?

Originally posted by bentrox!
Where are your priorities? Your Lemond will survive the heat just fine. If you're going to use the AC, reserve it for the beer, okay?

:) That is what the cooler in the back is for !!! Gotta keep my Sammy's nice and cold !

Jeff