Exploding inner tube

wallace_and_gromit

I had a lucky escape on Sunday. 2 minutes after descending at 80kmh, my rear tube exploded and the rear tyre came off the rim for around 1/4 of its circumference. Fortunately I was stationary at the time having stopped to dump some rubbish in a bin. Not sure what would have happened if the tube had gone whilst I was descending. :shock:

Anyway, the rear tyre had been in place for 500k without any prior issues and the rims were stone cold when the tube exploded, so I'm curious as to what might have casued this. (The tyre is fine, and with a new tube fitted, I rode a further 80k with a lot more fast descending, but with no incidents. The tube that exploded was quite and old one.)

Any thoughts as to what the cause might have been? Or were the Cycling Gods just out to scare me?

Thanks.

danlikesbikes

Had a club mate park his bike up after a 5 mile ride to meet up with the group, after about 10 minutes of chatting his rear went bang for no reason. Some people thought it was the sun, others heat from the rim even though only a short ride ever did find the reason though.

Could have been heat transfer from the road and or use rather that just heat from the rim?

Would put it down the to the Gods myself

sungod

the tube has to escape from the tyre to explode, i.e. first the tyre bead unseats, then the tube goes bang

likeliest is that the tube was nipped between tyre and rim - i've had it happen, also after a descent, i'm sure i must have nipped the tube then it just took a while before it finally snuck through the gap and exploded, maybe the braking/cornering forces on the descent flex the tyre enough to trigger the final step

otherwise faulty rim and/or tyre

even if the tube suddenly dematerialised the tyre would probably just deflate gently, not go bang

wallace_and_gromit

Thanks for the suggestions, guys. A "nipped" tube, pushed past the point of no return by the forces on the descent seems reasonable. The tyres are quite tricky to fit (so nipping is a significant risk) and I was racing a friend during the ride, so descending and cornering was much more aggressive than has been the case since the tyres were originally fitted!