Bizarre inner tube problem

[TomHammersley]

Hello all,

So, on Friday I had a puncture. I swapped out the tube for my patched-up spare, rode home, not a problem.

I thought I'd swap the patched one out for a new one on monday night. In went the new one, pumped it up, and it blew out. I thought I'd just pinched it or something when I installed it, so I carefully put another one in, pumped it up, and it *seemed* ok.

Came back to the bike the next day, and the rear wheel (where I'd swapped the tube) was flat. The new tube had a hole in it. I took the tube out and the tyre off, checked everything for debris, nothing to be found.

Since then, I've put in 4 different tubes of various types, both old and new, always being sure that I hadn't pinched them, and making sure there was no debris around. Every time, the tube blew about 100-110 psi, with the tyre feeling notably more difficult to inflate around that point.

I'm at a loss. I can't find any debris inside the wheel to explain the problem, having removed the tube & tyre multiple times and cleaned it out. Every time it blows out about the same pressure, so it seems there is something at play. I've checked the rims, can't see any problems there, no burring or anything.

Any ideas? I'm at a loss, and it's on my best bike too, so alas I cannot currently ride it!

The wheel is an 08 Khamsin, Pro Race 3 tyres, and a mixture of continental, specialized and random unbranded tubes.

Thanks

 

[Smokin Joe]

Have you got a spoke poking through the rim tape?

 

[shimano]

it's either a pointy bit of spoke or something poking through your tyre that only is revealed once the tube is at high pressure. Try swapping in your front tyre and see if it still happens to eliminate one source.

 

[MessenJah]

Sure there's not a hard-to-spot hole in your rim tape? If so, at high presure the tube will pop through the hole and burst.

 

[hubgearfreak]

I thought I'd swap the patched one out for a new one on monday night.

why?

 

[gbb]

Check your rim perhaps ?
Ive put nicks in my rims before, using metal tyre levers. I've found a sharp sliver of metal sticking up before.

 

[yenrod]

TOM: Try this: Check the valve hole is their any burs/sharp bits around it ie when you put valve in the hole it could pinch it OR you may well have a sharp bit in / around the rim.

OR: IT COULD BE A PIECE OF WIRE IN THE TYRE what you haven't found ie a strand of cable etc...

All the above have happened to me.

TRY A MilliMetre SEARCH

 

[Blue]

I once had a similar problem that turned out to be a delaminating tyre - under pressure the inside of the tyre was ripping the tubes. The problem was only seen when the tyre was turned inside out and flexed.

 

[TomHammersley]

Thanks for all the ideas guys.

It turns out that the inner tube was bulging out through the hole left in the tyre from the puncture. Once the pressure got high enough, the tube would burst.

Strange, I knew there was a small hole but didn't think it was big enough for that kind of problem to occur. Now I know better!

I'm guessing it's now time for a new tyre. If its big enough for the tube to escape, then it's big enough for grit and other nastiness to get in and cause further problems.

Thanks guys.

 

[02GF74]

well you've sorted it but I was going to say fit the tyre in same orientation as it was fitten; when removing t he tube, find where it has blown as see how that corresponds to the tyre/rim - narrows down the seraching considerably, especially if the inner pops in the same spot.

 

[byegad]

It would help if you could tell us where the puncture is each time.

 

[Maz]

It would help if you could tell us where the puncture is each time.

I was about to ask the same thing.
Is it at the base of the valve, by any chance? I've had a few inners burst on me just there. In my case there were no sharp edges on the rim hole so possibly a batch of rubbish inner tubes. I buy Schwalbe tubes now.

 

[TomHammersley]

The hole in the tube was always in roughly the same place, aligned with the hole in the tyre.

I put a cheap old spare on last night, all fine.

Bit irritating as it was a good tyre, and I'd only done about 1000 miles on it.

 

[Night Train]

Could you not put a patch over the hole inside the tyre?

 

[TomHammersley]

I wondered about that... but to be honest, the hole, whilst not enormous, was big enough for a decent bit of grit/glass/WMD/whatever to get in there, and it'd soon work its way through the patch and start nibbling away at the tube.