Got a puncture, but don't know how...

[Maz]

Went back to the bike to go home and noticed straight away I'd got a flat.

Took off the wheel and inspected the tyre inside and out...couldn't for the life of me see any holes in it (it's got some kevlar lining stuff, so seems to be doing its job). Checked the inner tube and it wasn't obvious where the puncture was. Anyway, I put the spare inner tube on and re-fitted.

When I got home I checked the old inner and the puncture was right at the base of the valve...not repairable. I can't figure out how I got a hole in that place.

Anyone had a puncture like this? What might have caused it?

 

[Steve Austin]

Happens a lot on MTB tyres. Caused by inner moving within the tyre and the inner catching on the sharp edge of the hole in the rim.

Check the hole for burrs.

Can happen more often under heavy braking when the tyres not inflated very much. not very common tbh, just unlucky

 

[Maz]

Thank you, sir. I will look for any sharp edges etc near the hole.

 

[RedBike]

It can also happen when you're inflating the tyre. The pump pulls the tube.

 

[Odyssey]

Yeah, what the others said. I've had loads over the years. Even occasionally ripped the valve right off.

 

[briank]

It's also a natural place for a weakness in the manufacturing process to show up. After all, the rest of the inner tube is just a big, thin, continuous doughnut of rubber, but the integrity of the whole thing is compromised by shoving a valve through it. All the rest about pumping up roughly etc is true, but it's still a natural point of weakness and sometimes the tube just fails there. There's virtually no chance it was a real puncture.

 

[Joe24]

I've had them go at he valve before. 3 of them. I pulled the pump off(track pump) and with my heavy handedness i pulls the valvle down slightly and tore it. 120psi going unexpected when my hand was there was a huge shock

 

[Globalti]

You probably already had a small hernia....

 

[Bigtallfatbloke]

That is where most of my punctures happened...the valve (presta) moved around to much when I pumped up the tyre and the rubber slit where it joins the valve

 

[CopperBrompton]

You can also just get duff tubes. I had one recently where the tube suddenly (and noisily) deflated while the bike was sat in my hallway. Nothing found in the tyre, but a big rip in the tube.

Ben