# Leaving bike in a car on a hot day



## Aeryn (Mar 8, 2008)

I brought my bike to work, so I could ride it at lunch. It stayed in the car the rest of the time. It got close to 90 degrees outside during the day, but probably was much hotter inside the car.  Did I do harm to the bike by leaving it in the car in this heat? Do I need to do anything special to it before riding again?
Thank you!


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## iliveonnitro (Feb 19, 2006)

No, it's fine. I've heard of an occasional tube exploding, but nothing more than that. It's a machine of various metals/carbon/rubber/plastics. Even most plastics have a melting point greater than the boiling point of water -- not that there's any low-melting point plastics on your bike (that i know of).


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## cyclust (Sep 8, 2004)

Just don't take a swig from your water bottle if it was in there. Coffee like tempature with that Oh-so-good plastic flavor!


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## buddyp (Aug 27, 2007)

I had a tube explode doing that once. Just make sure your pressures are well below the max and you will be fine. 

BTW, There's no reason to run tires at extreme pressures unless you are a huge person. For an average sized *cyclist* 7-8 bar is plenty, which is well below the max inflation of most quality tires. 

If you do need to run them near the max inflation let a little air out when you put the bike in the car and bring a pump and air them up before you ride. Don't forget to let a little out when you are done riding.


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## Dave Hickey (Jan 27, 2002)

+1 on the tire pressure on hot days... Let a few pound of pressure out and you'll be fine..

I also cover the bars with a towel...aluminum bars get very hot to the touch while sitting in a car all day....


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## jupiterrn (Sep 22, 2006)

You should always leave a window cracked and leave plenty of water for your bike to drink while you are at work. JUST KIDDING. I have nothing more to add, should be fine unless it is carbon and bursts into flames. Sorry kidding again. Oh, I thought of something real. As Hickey said put a cloth over the bars and SEAT. Black seats and sunlight not a good combination if you just jump right on.


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## mohair_chair (Oct 3, 2002)

I often leave my bike in the car on very hot days. I've done it for 10 years. I take no precautions and have never had any problems. It's no big deal.


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## capt_phun (Jun 14, 2004)

I saw on Mythbusters where they put a bike in a hot car & it exploded and killed the person in the front seat. Oh wait, that was a can of biscuits.


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## mohair_chair (Oct 3, 2002)

capt_phun said:


> I saw on Mythbusters where they put a bike in a hot car & it exploded and killed the person in the front seat. Oh wait, that was a can of biscuits.


Was the car on a conveyor belt?


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## Mr. Versatile (Nov 24, 2005)

No, no, no! See...this is how rumors get started. What capt phun said is just wrong. They were using their dummy in the front seat because they fully expected something to go wrong. So the truth is, no one was killed, but the dummy was permanently maimed.


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## fakeplastic (Aug 5, 2006)

the only other thing i'd be concerned with is if you have CO2 cartridges in your car. the ones i bought recently said not to expose to temperatures higher than 49C (about 120F). its possible the car could get up to that temp on a really hot day.


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## Aeryn (Mar 8, 2008)

Thank you everybody! I left no water bottles, co2 cartridges, or over inflated tires in the car, so it's all good


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## ZoSoSwiM (Mar 7, 2008)

Don't leave your helmet in your car.. Cover your cycling computer so the sun doesn't fry the LCD... Direct sunlight for hours on end isn't good for anything..


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## Aeryn (Mar 8, 2008)

ZoSoSwiM said:


> Don't leave your helmet in your car.. Cover your cycling computer so the sun doesn't fry the LCD... Direct sunlight for hours on end isn't good for anything..


Is it the heat or the sun light that's bad for the helmet. All the stuff was covered so protected from the latter, but not the former.


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## ZoSoSwiM (Mar 7, 2008)

well.. I would think both are bad.. direct sun for a long time can melt plastic. When it's on your head you've moving and it keeps cool. The foam and such might also melt or become weakened. I doubt a few times left in a hot car will destroy a helmet.. but after a while I bet it will harm it enough to make it not so protective.


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## Kerry Irons (Feb 25, 2002)

*Heat and light*



Aeryn said:


> Is it the heat or the sun light that's bad for the helmet. All the stuff was covered so protected from the latter, but not the former.


Sunlight can degrade plastics, but it doesn't happen in hours or days or weeks. Years is more like it. Besides, the car window glass is a great UV filter, so you don't get much of that when something is behind the glass. Heat is the issue inside a car, particularly if the item is in direct sunlight because the temperature can get much higher than the air temp, which already is pretty high. If you just put your helmet on the floor of the back seat so it's in the shade and down low, you certainly will have no issues.

The only experience I have had with bikes in a hot car is that the temp can get high enough to soften the glue on a patch and cause a patched tube to go flat.


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## ZoSoSwiM (Mar 7, 2008)

I guess my point with the helmet is why risk it... how much is your brain worth?


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## nor_cal_rider (Dec 18, 2006)

I didn't use to think much about this as I typically leave my front windows cracked. This weekend we had the first real heat of the summer - got up to 106-108 depending on where you were in town - and I had forgotten to roll my windows down. No big deal, except I also had left my mtn bike in the back from a ride last week....got in this morning and saw the front tire was completly flat. Moral of the story...try not to leave your bike in the car longer than necessary and remember to crack the windows in the summer (would have remembered this except I didnt drive last week due to 'Bike to Work Week').


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