Rupturing inner tubes

carlosestinos

Hello All,
I’ve recently started commuting to work. The bicycle I’ve bought is specialised tri-cross elite. It is kitted out a winter bike really.
• Rear rack
• Fenders
• Lights,
• Tool kit, spare inner tube
• Pump
• Water proof detachable pannier
Id actually bought the bike about two months ago and had covered roughly 150 miles (not commuting) prior to me using it for my daily commute. Last week was my first full week.
The other day i decided to put some air in the rear tyre, i tapped the end of the presta valve and proceeded to put some air in, all of a sudden the tyre lost all its pressure, i thought this was somewhat unusual as I hadn’t over pressurised the tyre. When I took the tube out I noticed that it had ruptured where the valve joins the tube (picture attached) I duly replaced the tube with my spare and off I went to work the following morning. Roughly half way through my commute (my commute is roughly 5 miles) the front tyre completely deflated. I tried to pump the tyre back up but i could tell by the way it deflated that it wasn’t going to pump up! So then, as I had used my spare the previous night I had to walk to work 
Upon inspection of the tube it had ruptured in the same place. I put this down to both of them being a cheap inner tube. I had replaced both the burst tubes with continental inner tubes. I thought this problem was short lived, and I even decided to carry two spares to never come up short again!
Today I went out for a spin, and to my despair the rear tyre lost pressure again. This was a continental inner tube, so I had the joy of carrying out a roadside repair in the icy wind and rain. Having now got home and inspected the inner tube it had also failed in the same place. There definitely seems to be a recurring problem. And I don’t think it’s a batch a faulty inner tubes
That’s the outline of the problem. The tubes that the bike came with, the valves didn’t have a lock nut on. When I replaced the first burst I assumed that the lock nut had to go on the inside of the bicycle rim. And this is firstly something i wanted to check, is this correct place for it?
I’m intrigued to hear if anyone else had had this problem with inner tubes failing at this point and if so what is the root cause of the problem?
Any feedback would be gratefully received

Carlos

raymondo60

I'd first check the inside of the wheel rims, if you haven't already, make sure there aren't any bits of debris/sharp edges around the valve holes. Also, are you inflating the tyres to their correct pressures? It is possible to have a 'bad batch' of tubes - I'm sure that's happened to many cyclists here, as it has to me. Personally I don't bother with the lock nuts that come with inner tubes but that's a personal preference. Lastly, it is possible to sometimes damage the tube right by the valve by being a little too 'heavy handed' when pumping them up - valve stems are delicate mechanisms so go easy when fitting the pump etc.

Good luck.

ricky1980

poor quality tubes? bad installation method? no rim tape or rim tape not aligned to the valve hole causing some kind of pinch point? the lock nut is not tightened once pumped up? low tyre pressure?

I had a continental tube failed in similar fashion. I bought it from a very cheap place...i think they were fakes! I have no issues with any subsequent continental tubes.

BigLights

What size are your tubes? I have a theory. My colleague on 23's keeps getting punctures, but his inner tubes are 18-23s, which means they're going to be maximum stretched all the time and more prone to punctures. I use 23-28 tubes on a 23 wheel, which in theory means the the rubber is not so stretched out.

Just a theory, though.

pdw

When I replaced the first burst I assumed that the lock nut had to go on the inside of the bicycle rim. And this is firstly something i wanted to check, is this correct place for it?

Not quite sure what you mean by "inside". You push the valve through the rim, then screw the lock nut on, but don't screw it on too hard.

Does your pump have a hose, or does it attach directly to the valve? If the latter, you need to be careful when pumping not to damage the valve.

One possibility that is consistent with the damage, and the recurrence of the problem, is that the tyre and tube are slipping on the rim. Never seen it myself, but Google suggests that it can happen (e.g. http://forums.bicycletutor.com/thread-1675.html). The suggestion of marking the alignment of tyre and rim should quickly rule this in or out.

carlosestinos

pdw wrote:

One possibility that is consistent with the damage, and the recurrence of the problem, is that the tyre and tube are slipping on the rim. Never seen it myself, but Google suggests that it can happen (e.g. http://forums.bicycletutor.com/thread-1675.html). The suggestion of marking the alignment of tyre and rim should quickly rule this in or out.

Thanks for all the reply s, yes I probably wasn't being very clear there with the lock nut, but indeed I have it outside the tyre against the rim. In all honesty I believe that the tyre is moving with the inner tube, what's consistent with this is that the tape on the inside of the rim is always crimped up as if the whole thing has compressed/stretched clockwise, and consequently the valve does not stick out of the rim perpendicular, its at an angle after the bikes been ridden. Im going to mark the tyre up and see if I can observe this movement in the tyre in relation to the rim(as suggested in that other forum post link pdw put up) I've just put some new winter tyres on today(schwalbe spikes) so might not get a fair reflection of the problem I was experiencing.

father_jack

Check tyre pressure
Check inside of rim doesn't have any sharp edges.
No loose glass rattling around rim
Check spokes and nipples
Check rim tape.

Initialised

Lock nuts both inside and outside of the rim should stop this from recurring also might be worth cutting a protective shim from a busted tube to reduce any chaffing of the tube from material around the hole.

ricky1980

Initialised wrote:

Lock nuts both inside and outside of the rim should stop this from recurring also might be worth cutting a protective shim from a busted tube to reduce any chaffing of the tube from material around the hole.

no way, lock rings inside a rim?! that will cause more punctures and shears.

check your tyre pressure is at least 100PSI, if under inflated there will be a lot of movement which will cause this kind of problems.

Also the rim tape is properly aligned with the vale hole.

MrChuck

Is the tube the appropriate size for the tyre?