Bicycle Mechanics - Cruiser bicycle: 26 inch tube keeps tearing near valve

Hello,

My wife has a nice cruiser bicycle from Beick (in the Netherlands). She had a flat tire a few weeks ago and I replaced the rear inner tube. The wheels are 26 inch and I've used 26x1.75-2.3 for the inner tube.

Unfortunately I'm now replacing the inner tube for the 4th time: it keeps tearing near the valve. I've checked the rim and tire for sharp pieces several times and I'm quite sure it has nothing to do with the tube being teared by the rim or tire.

As you can see on the pictures the tube tears at exactly the some spot near the valve. After about 10-20 minutes riding the bike, the valve looks like the second picture. It seems to be almost diagonal on the rim.

I tried several things, including fully inflating the tire afterwards without the small ring being tightened. (so the loosened ring on the picture is on purpose :)). I also tried several different brands for the inner tube.

Does anyone has a suggestion for fixing this issue ? I get the feeling that I'm doing something completely wrong, although I've successfully replaced several inner tubes on different bicycles.

With regards,

Rutger

Is it possible that the tubes are at fault? Try a different source when buying a new tube.

Well, unfortunately I already tried three different brands and the result was the same. Could it be the size of the tube ?

I think you may need to use more air pressure. The tire isn't being held in place securely and is "walking" around the rim as you pedal.

Ok, that's interesting. What kind of pressure is reasonable for a cruiser bike ? According to the tire it should be a minimum of 30 psi and a max of 60. Any suggestions (for comfortable riding) ?

I fill mine to 45-50 psi. 26x2.125

Your picture shows a Presta valve. Are you sure the rim isn't drilled for a Schrader (automotive type) valve? If it is, the hole is too large for the Presta and doesn't support it so the failure is to be expected. There are grommets and/or inserts that will let you safely use Presta valves in a rim drilled for Schrader valves.

Your picture shows a Presta valve. Are you sure the rim isn't drilled for a Schrader (automotive type) valve? If it is, the hole is too large for the Presta and doesn't support it so the failure is to be expected. There are grommets and/or inserts that will let you safely use Presta valves in a rim drilled for Schrader valves.

Seconded. As soon as I saw the pic, I wondered how in the world it would be possible to get a valve angled 45 degrees in a correctly-sized hole.

Seconded. As soon as I saw the pic, I wondered how in the world it would be possible to get a valve angled 45 degrees in a correctly-sized hole.

The tire would still have to walk around the rim for that to happen. I'd try 50 PSI.

When I got My Snow Cat rims for my studded tires,
they reccomended for winter riding at lower PSI,
I use sew up glue, to glue 1 bead to the rim, to prevent torque 'walking'..

if you want to ride your beach cruiser with soft low pressure in the tires
I'd suggest you do that for that purpose, too.

You mend punctures , by dismounting the un glued tire bead.

Seconded. As soon as I saw the pic, I wondered how in the world it would be possible to get a valve angled 45 degrees in a correctly-sized hole.

I've checked, it's actually a Woods valve (quite normal in the Netherlands, btw). The inner tube on the front wheel has also a Woods valve and has never been replaced. I noticed that it's also a bit angled.

Are you pulling on the valve too much when you're pumping up the tire?

Are you pulling on the valve too much when you're pumping up the tire?

I'm leaving the valve as it is while pumping up the tire, to avoid unnecessary tension on the inner tube. Unfortunately, that doesn't seem to help either.

I must say that I'm starting to feel quite stupid for not being able to replace an inner tube. :( If the bicycle was still under warranty, then I would surely returned for service. It's a great bicycle, except for the lousy service of the manufacturer.

Try putting some double sided tape on top of the rim strip/tape to keep the tube from sliding around on the rim.

Heck, maybe the rear tire is oversized from a manufacturing defect ( And or a slightly undersized rim )? Tape, glue, and increased pressure are all well and fine, but it would suck to have to try to fix it by dealing with symptoms and not the root problem.

Can you obtain valves with fully threaded stems? If so having a nut on the stem on the inside of the rim as well as on the outside, both tight against the rim, may immobilize the valve sufficiently to avoid it getting bent sideways and straining the tube.

Can you inconspicuously mark the tire and rim to see whether they are moving relative to each other? This might give you a clue as to what is going on.

I googled a picture of a woods valve and look at that! The nut that the OP had screwed part of the way onto the rim is supposed to be screwed onto the rim like a presta nut. I personally do not use presta nuts because I run my tires at high pressures.

http://upload.wikimedia.org/wikipedia/commons/thumb/1/1f/Dunlop_valve.jpg/328px-Dunlop_valve.jpg

OP: Do that and your troubles should go away.

Check the direction that the tube is apparently rotating in. I'd suspect its most likely the result of braking forces causing the tire and tube to rotate on the rim. For most riders - braking forces are stronger than acceleration forces. Riding with a higher tire pressure usually solves the problem.

The tire isn't being held in place securely and is "walking" around the rim as you pedal.

+1

But braking is more likely to be the cause of tire slip on rim.


I think you may need to use more air pressure.

Easiest fix, certainly. I've had folding tires that's been b@stards at this. A smear of liquisole on the bead (made it less slick) took care of it. Extreme cases, glueing may be called for.

OP: Do that and your troubles should go away.

No.

If root cause is tire slipping, you won't cure that by securing the valve. The valve will jam as it angles, and it has still managed to tear.

Well, MAYBE there's some borderline case, where the marginal retaining force offered by the valve would suffice, but I wouldn't bet on it.

Use a schreader valve as substitute for woods, will fit hole in rim better than presta. possible that narrow presta valve is exposing too much rubber thru the larger hole resulting in stretch+tear.

Make sure valve is inserted straight, after putting about 20psi, tug the valve to ensure it is fully seated flat agaist inside of rim; unseated valves can lead to a gap inside rim which then lets inner tube form a 'bubble' that stretches too much and tears.

Inflate fully to 60psi; low pressures can lead to tire+tube 'walking' around the rim leading to skewed valve which then tears loose at base.

Note: second photo: cross hatch marks on tire sidewall indicate damage from riding with underinflation, be sure to reinflate more often and to do so fully.