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Innertubes And Heat. Do They Expand ?


dann2707

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Hey.

I left my bike in my car overnight in the driveway and I got it out this after noon I noticed the rear tyre was flat which was odd as 100% it hadnt punctured as I rode it to my car last nights ride.

Ive come to see where it had punctured and its around the base of the valve its like split.

I dont have back seats in my car and the bike was on show through the windows so as you can imagine the back of my car was like a f**king sauna when I got it out.

Im guessing the heats expanded the innertube and split the valve?

shame as I hadnt had a rear puncture in over a year :(

Saving grace is that it was a kenda heavy duty mother fugga so ive save 240g changing it for a normal tube.

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Think about it logically, all the heat is going to do is expand the air in the tube which is akin to pumping it up harder, unless it managed to temporarily inflate it beyond the tyres capacity to hold the tube (in which case the tyre would be showing signs of failure) then I'm going to guess that the valve neck has been rubbing and gone through. Especially if you have low pressures the valve stems tend to shift around a lot and rub on the hole.

Also please don't leave your bike in the back of the car, especially uncovered, I did it once overnight, lost my bike and 250 quid to fix the car :(

I live in a pretty decent area as well.

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Ahhh interesting! So it must be just general riding fatigure. Its just weird as its like a proper cut not like a chafing mark.

Its right at the bottom of my drive with 2 cars behind it over night. If it was on the street I wouldnt have left it in.

Poor kenda tube, its done me quite well though.

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I had a cheapy tube do exactly as you describe on friday as the bike was chilling in the sun.

It was a bonded valve where the valve is attached with a circle of rubber at the base of the valve glued to the main tube, cheaply.

My best guess is that direct sunlight, black moto digger, shiny black combat rim and 45 odd pounds made it incredibly hot and stressed in there and the glue melted, leaving me to carry and push home for aproxx. 3 mile :angry:

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P = RT/V

Assuming the temperature increase/fluctuation is small enough to not cause a variance in volume, then it should be pretty obvious that as Temp increases, so does Pressure. So yes pressure increases, however as Forteh said unless its increased loads (ie, not from 10 degrees to 30 degrees) its not going to really cause a blowout!

consider your answer quantified!

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