So my bike is quite handy and I like it. However it has been really annoying because it always fails from the exact same spot. Right beside the valve. I have attached a picture of the puncture and how does the inner of my wheel looks like.
Help.
by HeavyAd1191
25 Comments
Often this comes when you let too much air out of the tube and the tube/tire slips a little bit on the rim, or from installation issues.
Not sure. But my best guess would be old rubber ? So it is slightly degraded. Try flexiable valve stems
Use a pump with a gauge, check pressure more frequently. You are riding the bike with slightly under inflated tires and the valve is tearing away because you are using threaded valves. Under inflated tires slowly rotate around the rim and tear valves off.
Looks less like a cut and more like the valve was pulled from the tube.
Do yourself a favour, do not use the washers to secure the valve, you’re likely over tightening them and pulling the valve from the tube. They also are prone to rattling and serve no real purpose.
Under-inflation causing the tube to rotate inside the tire.
Make sure that when removing the pump head from the valve, push it off rather than pulling it off. This is often caused by what others are saying. It is also caused by removing the pump head with a diagonal force, putting all the force on one corner of the valve bonding.
Or the bead of the tire is sitting on the shoulder of the valve, the thicker area around the valve. Make sure when you install the tire to push the valve up into the tire, then pull it out with the beads under it to inflate.
Be careful not to overtighten the retaining ring.
Are you putting the tube in the wheel as pictured?
You need to remove that washer.
In my experience it’s bad rim tape at the valve opening
You may be better off leaving that nut off the valve stem. It may not be the problem, but it eliminates one strong possibility.
If your using CO2 there’s a chance your filling it too fast, and its freezing there. The other thing is that you might be tightening the nut down too tight. Tighten in gently when the tire is flat, avoid the urge to tighten it down all the way once the it’s pressurized. The nut isn’t there to secure it tight, it’s just there to keep it from slipping inside when you put the air chuck on.
I’d also check the rim tape around the valve hole to make sure it covers the hole properly and that there are no sharp edges.
i had theese problems with rim brakes on long descents, when they get hot.
Check for sharp edge on the valve hole on the inside of the rim and sand it a touch to make it not sharp. Also try different tube vendor, could be quality control issue on the tubes.
Valve nut and low tire pressure. When you pump up the tubes it pushes the tube and the valve out. As the tube loses air over time it starts to shrink and pull away
Overtightening the knurled jam nut pulls the tube into the hole in the rim and causes it to tear.
Get rid of the nut. It isn’t needed for tubes.
On larger tire sizes, I would put the nut INSIDE the rim to 100% prevent this problem. On an 18c, though, space will be a little tight, you might just leave the nut off on the outside. But if you can find even a washer to put over the tube threads and leave that washer inside the rim, if will prevent the valve-adjacent flats.
Overtightened, rim tape or wheel has sharp edges.
More info please – what pressure do you put in your tyres, and about how much do you+your bike +your load weigh? How wide are your tyres?
I’d suspect the tubes+tyres are moving on the rim, twisting the valve in its hole and fretting against the hard rim. You may also have some burrs or sharpness on the inside of the rim.
Another possibility is the brand of tube is just a bit rubbish and the seal between valve and butyl rubber isn’t very good. Try another brand – schwalbe is a good brand of tube for example. May have to spend a little more sadly.
That little collar nut – are you putting it on the valve stem after it is installed in rim? are you overtightening it ? Should be just finger-snug, no tools needed.
Baby Powder the inside of the tire prior to tube install
This happens when the tube sticks to the tire.
One other thing to mention, I’m curious what the size/length of the valve is. If you don’t have dished rims you may want to consider getting a shorter valve. If the valve is too long you could be putting stress on the tube unnecessarily when airing up.
To add to some good comments made by others, I had a pair of rims once that caused that. The holes for the value stems were a little big, and (I should have deburred them) a bit sharp.
I ended up making a couple things leather washers to go around the stems.
sharp edge on the valve hole
burr or something
I had an older tire that was stretched out and was allowing the tire to slip and tear the tube at the stem. A new tire fixed the issue.