Inner tube blowout, any ideas why?

JamesB

Going downhill late this afternoon, about 30 mph. Fairly smooth roads didn`t hit any gravel / stones I`m aware of; suddenley inner tube front blows out lifting tyre (Mich Krylion) off rim (brand new tight fitting tyre too ).
Very fortunately manage a stop without crashing as tyre flapping around rim; rim is warm but not hot. Inner tube has long split on `inner` face ie onto rim bed, no signs of any spoke protrusions etc on rim.
Tyre has an inch split just along beading, just managed to fix with tube patch and foil and limped home; wheel rim is damaged, and now out of true.

Tyre and tube as far as I can see was fiited OK, any ideas what went wrong? had just been around tight corner so very lucky ??? this happened when it did. Big bill now new tyre and possible wheel rebuild (DT swiss 415 / Tune radials) costs

eede

If it's a tight fitting tyre, is it possible a bit of the tube was caught between the bead and the rim? I check for this pretty meticulously having done it myself causing a loud unexpected bang and a split exactly as you describe.

sungod

to go bang and split, the tube has to be outside the tyre

mostly likely is that the tube was pinched between tyre and rim, this can sometimes be ridden quite a while before it goes bang

rim or tyre bead damage/wear is another possibility, but i'd go with pinched tube

JamesB

is it possible a bit of the tube was caught between the bead and the rim

this is possible , although I did check very carefully as on first fitting a bit of inner was caught and I started tyre fitting all over again--but may have missed out a bit maybe?? , or the pinched inner was weakened ? bad experience but knowledge of why will reassure

kozzo

Happend twice with Continental inner tubes... never with Michelin and Vittoria
Personally I don't trust Continental at all.

singleton

Interesting topic.

I had a continental race light tube do this to me a few months back. Rear wheel, loud bang and a 3 to 4 inch split in the tube. I had always used conti race tubes before and put this problem down to the 'lighter' tube letting go. I replaced it with a conti race and not had any issues since - but maybe there was more to it than I first thought...

sungod

the thinner the tube, the easier it is to nip it between tyre bead and rim - done it myelf - i find that with the race lights i need to be more careful than with the plain race 28s

desweller

Pinched tube.

Two techniques I use to avoid this:

1. Dust the inside of the tyre with talcum powder to help the tube find its way inside.
2. When the tube is partially inflated, make your way round the whole tyre, rocking it back and forth in such a way that you can see the rim tape from either side of the wheel.

balthazar

This is one of the failure types you can be sure about- the tube is always innocent! As Sungod says, the tube must be outside the tyre to explode, which means the tyre bead must have escaped the rim. The usual cause of this is that the tube is trapped under the bead.

It cannot ever be caused by the tube because no tube can support high pressure without the tyre. All other puncture causes (tread penetration, exposed spokes, rim tape failure, valve seat failure etc) have different consequences.

sturmey

i had four different inner tubes (two were lightweight butyl and two latex) burst like this on a brand new dura ace wheel. i can only guess that some rims ALLOW this to happen.
In the end the only thing that worked was a standard heavyweight tube. I have never had this problem with any other wheel.