Serial blowouts

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sungod
Posts: 1702
Joined: Fri Dec 24, 2010 9:37 pm

by sungod

to go BANG the tube must be outside the tyre

even if a tube is really poor quality/faulty, it won't go BANG if it fails inside the tyre, it'll just go sssssss

typical causes...

tube nipped between bead and rim - pressure slowly (it can take many hours) forces bead off rim
tyre bead faulty/damaged - bead slips off rim
rim worn/damaged - rim deforms, bead slips off rim

...in each case, the result is tube protrudes, BANG

try inflating the tube slightly before fitting, that greatly reduces the chance of nipping it

also take careful note of tyre and tube position wrt to rim, then if you do get another failure you can look at the corresponding areas on tyre and rim

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mrfish
Posts: 1749
Joined: Wed Mar 28, 2007 12:49 pm
Location: Near Horgen, Switzerland

by mrfish

+1 it's either a small bit of glass or something in the tyre, or a bit of debris in the rim.

I've had a set of rims which required a few blobs of epoxy to fill minor depressions in the carbon, plus tyres which looked fine but would puncture a tube after 1 hour of riding.

To diagnose it is to mark the tube and tyre so that when you take it all apart so you can roughly locate the area causing the problem.

madmole
Posts: 138
Joined: Thu Nov 17, 2011 4:29 pm

by madmole

I've heard numerous tyres go "Bang" over the years, totally within the tyre and no bulges or protusion, but in every case it was a bulge into a spoke hole (so not the cause this time)

So if its 10" away each time, is the hole in the outside or the inside of the tube. Inside its the rim, outside its the tyre

Could it be that the tyre is now old and weakened by past blowouts that the kevlar/wire bead is weakend and is moving in the rim and pinching the inner tube (hole will be in side of tube)

I'd try a new tyre

Oh and supersonics for me are one of the most durable inners there are. They are like the latex tubes in that they are flexible enough to deform around protrusions and my experiance is that they puncture less and are as durable as any normal tube, plus they give a much better ride. I even use them in my mountain bike !
Cervelo S3 2011. Blinged 6.718 Kg

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WMW
in the industry
Posts: 893
Joined: Sun Jul 29, 2012 2:59 pm
Location: Ruidoso, NM

by WMW

Regret wrote:The blowouts are not at the valve hole. They are at least 10 inches away.


Are they always 10 inches away?

A blowout (explosion) can only occur if the tube's container *suddenly* fails. This is never the fault of the tube. It must be something to do with installation, loose tire bead, or a hole in the rim that tube slowly protrudes into and then explodes.

What tire is it? Does it seem tight?
formerly rruff...

Regret
Posts: 27
Joined: Wed Mar 28, 2012 12:53 pm

by Regret

Ha!

WMW's comment made me look again. It turns out there is a crack in the tire, hidden in the maker's logo. Very small, and not noticeable through inspection. It didn't turn up until I changed the tube, inflated it and went over it again. Can't believe I and my mates missed it all those times.

Rookie mistake I know, thanks for all the input.

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WMW
in the industry
Posts: 893
Joined: Sun Jul 29, 2012 2:59 pm
Location: Ruidoso, NM

by WMW

Thanks for closing the loop!
formerly rruff...

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