About half an hour after my ride last night, I heard a hissing sound and quickly realized that air was escaping from my tire. Same problem as last time: a tear at the place where the valve attaches to the tube. This one was at least partly my fault; for at least the last few days, I’d noticed the valve was slanting, not protruding from the rim at a 90-degree angle, but was jonesing to ride so I did nothing about it. Looks like the rim bit into the valve and tore it open. I’m pretty sure that the reason this happened last night, and not during one of the other rides I went on since the valve started slanting, is that I deliberately rode over some bumpy grass last night.
When the bike shop installed this tube, I made sure the valve was poking out of the hole at the correct angle. Not sure what caused it to start slanting. Is there something about unicycles that makes them prone to this problem? I’ve got to find a way to prevent this from happening.
first step - check your rim tape to see that it covers up the valve hole’s edges.
If not - get an old bit of tube and cut an X into it, poke your valve through that, then put the whole thing into the valve hole, similar to a tubeless tape-type setup. Apparently this setup is common for FOSS tubes to prevent the problem you’re having, but it works with regular tubes too
Not sure if this is recommended, but if your valve hole is extra-sharp, you might be able to file it down a bit to smooth the corners off. Wait for others to confirm if this is a good idea though!
I decided to order tubes and tire levers and do the replacement myself this time, so that if this happens repeatedly, at least I won’t be paying the bike shop a labor fee. I looked up how to change a tube on YouTube just now, and it seems pretty easy.
changing a tube is the easiest thing in the world once you’ve done it a couple of times. You’ll never have to pay again!
Check the hole, if it’s got a sharp edge then sand this off, by hand with some FINE sandpaper, you want a nice smooth edge (on the inside - the outside shouldn’t matter but any sharp bits there should be removed too).
A rotating tube is normally due to a rotating tyre which is normally down to under inflation or a loose tyre/rim combination. Some tyres are just a bit “baggy” so if you run them a little low they tend to move.
Also check whether they used anything to make getting the tyre on easier - some use soap like products so the tyre goes on easier (like they do on cars) but this makes the tyre slip. Clean this off.
As a unicycle is pedalled a bit unevenly and doesn’t get any braking action (in most cases) there’s a good chance the forces are pretty much all in one direction and will add up over time. Check regularly, if you see it’s starting to angle then just let the tyre down and give it (and the tube inside) a little pull round until it’s straight again. Might be worth building into your regular checks like if your pedals, seatpost and bearing nuts are still tight. Also I forgot - you’ll be wanting to rotate the tyre anyway because of the flat spots you might start getting due to always starting with your feet a certain way - others would know how much this really happens.
One way to stop the tire from rotating on the rim is to use some rubber cement on one bead of the tire where it hooks into the rim. Paint it on, let it get almost dry then install like normal. That should prevent the tire from shifting on the rim but doesn’t wreck anything, allowing easy disassembly in the future.
That should really only be necessary for fat tires running low pressure but works on all wheels.
Definitely check the valve stem hole for anything sharp. I had that problem years ago when I had to buy a new wheel on a bike tour. There was a burr on the stem hole that ate thru the stem on me a few days later. I don’t remember how I fixed the rim though. I was a long way from anywhere. I must have had a small piece of emery cloth in a tire patch kit.
No, Catsmeat, the problem you describe is not particularly a unicycle problem. It did happen to my bicycle once, but never to any unicycle that I had.
It’s good that you’re learning to fix things yourself, as unicycles do have their quirks. A guy I know insisted on getting his tire replaced at a bike shop, and they put his wheel on backwards, with the right-threaded pedal on the left side. Eventually his pedals came unscrewed as he rode, so the threads got stripped and he had to buy new cranks. Besides, if you use this forum, you can learn how to fix just about anything that breaks on a unicycle, or even build a new one! Some people on this forum are welders, engineers, etc, and lots of us have built our own wheels. Some also build elaborate trials obstacle courses out of wood…
If it’s a persistent, ride-ending problem you might be able to go tubeless, which should eliminate this type of issue. I haven’t tried tubeless on my unis yet, but haven’t used tubes in bike tyres for years and haven’t had a flat since. I use Stans products on my mtbs. Someone else on here should be able to advise on tubeless uni setups. I expect I’ll try it once I put the duro back on my Nimbus muni, the only reason I haven’t yet is it makes swapping to different tyres a bit more messy!
I’ve been doing a lot of bike repairs as part of my job recently. I’ve seen a few tubes that are messed up in the valve stem area because of bad quality control at the manufacturer. I’ve pulled multiple dead tubes apart and found air bubbles in the rubber around the valve stem causing the holes. So it is possible that you got a bad tube.
As you already know, having the valve stem pulled to the wrong angle is more likely the problem though especially since you had a problem like this before. In case you don’t know, all you have to do to straighten the valve stem is let the air out of the tire and slide it along the rim. As saskatchewanian suggests rubber cement could help stop the tire from moving in the future but if you don’t really care too much about your pressure you could just try increasing it a bit to force the rim to hold the tire tighter. Removing sharp edges with sand paper is also a pretty nice idea. Good luck!
I blew so many tubes around the valve that I have lost the count.
the main reason: I tend to ride with lower pressure.
the main way to fix that: buy tubes where the valve can be screwed to the rim: in my case no such tubes ever had their valve ripped off.
Only problem: find such tubes (May I suggest that unicycle sellers also provide such tubes thanks!)
I used to get a lot of flats until I perfected my tire changing skills. I watched some guys at a bike shop do it a few times, and now I almost never get flats.
One key is to put the tube in the tire, put the valve in the rim hole first, then carefully put one bead in the rim, then the other. I’ve found that helps. But as others said, it’s also been the case that the issue has been insufficient rim tape, or something caught in the tire. More often than not, though it’s been tire changing technique, at least for me.