Page 1 of 1
Tube valve stem cut off
Posted: Sun Jun 14, 2020 12:28 pm
by jonathan
Besides low air pressure, what would cause a valve stem to shear? Tire pressure was 60 psi. The stem was still perfectly straight and stuck in the rim! I am using a flapper also, could that be a problem? Have about 2000 miles on tire and tube.
Re: Tube valve stem cut off
Posted: Sun Jun 14, 2020 12:47 pm
by Mark Gregush
Front or rear? Are your rims powder coated, painted or?
Re: Tube valve stem cut off
Posted: Sun Jun 14, 2020 12:49 pm
by BE_ZERO_BE
Most likely, the tire and tube rotated on the rim.
What kind of tire was it?
What kind of rim was it.
There are certain combinations of tires and rims that are prone to tire slippage.
I have had this problem since 2007.
Re: Tube valve stem cut off
Posted: Sun Jun 14, 2020 12:53 pm
by jonathan
Front drivers side. Hayes rim and riverside tire. Rim painted not powder coated.
Re: Tube valve stem cut off
Posted: Sun Jun 14, 2020 12:57 pm
by Steve Jelf
What brand of tube?
Re: Tube valve stem cut off
Posted: Sun Jun 14, 2020 1:03 pm
by Rich Eagle
I lost several like that in a particular run of Firestones in the 80s. All were at high speeds downhill. I did not use flaps then but do now and haven't had that problem with different tires since.
Re: Tube valve stem cut off
Posted: Sun Jun 14, 2020 1:05 pm
by jonathan
Hartford tube made in China
Re: Tube valve stem cut off
Posted: Sun Jun 14, 2020 1:55 pm
by Steve Jelf
Hartford tube made in China
That's a surprise. I was expecting Custom Classic. I haven't had that problem with Hartfords, but that may be because I replace the rubber stems with metal.
Re: Tube valve stem cut off
Posted: Mon Jun 15, 2020 10:18 am
by R.V.Anderson
If this is the flapper you were using, it could be a problem.
Re: Tube valve stem cut off
Posted: Mon Jun 15, 2020 11:35 am
by Original Smith
Try using a flap instead of a flapper!
Re: Tube valve stem cut off
Posted: Mon Jun 15, 2020 2:45 pm
by DanTreace
jonathan wrote: ↑Sun Jun 14, 2020 12:28 pm
The stem was still perfectly straight and stuck in the rim
Could be the issue, those rubber valve stems have a taper and can stick in place too soon, and not be fully up into the rim. That can cause the tube to be 'suspended' just beneath the valve stem, and allow the tube to bunch just a bit, and be like a loose pocket under the stem when aired up.
Also, don't see much remains of talc on the tube or around the stem, unless you wiped it clean on removal. Talc powder is needed to provide lube to the rubber surfaces and prevent chafing that can cause valve stem/tube interface issues.
Re: Tube valve stem cut off
Posted: Mon Jun 15, 2020 4:38 pm
by Adam
I air them up with no valve core in place and allow all the air to escape about 5 times before installing the valve core and final airing up. That allows the tube to move around inside of the casing and self align itself so there is no stress or bunching on the stem.
Odds are fairly good that your issue was the stem being stressed internally in some way.
Re: Tube valve stem cut off
Posted: Mon Jun 15, 2020 11:40 pm
by Alan Long
Yes, we all install Tubes with good intentions and care but nobody really knows what’s going on inside the Tyre!
Who would check or even know how to check if the Tube is the correct size and not manufactured too large or small with
over stretching or folds being a issue. Another reason to us Blockley. The Owner of the Business told me his Tubes are correct
and you can install them with knowledge they are the correct fit in the Tyre. Not suggesting this is the issue
with the initial question. Alan