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Rear tyre wont inflate.. Broken valve??

Discussion in 'Technical and Troubleshooting Torque' started by deXtrous, Sep 5, 2011.

  1. Hi, the tyre isn't popped or anything, or at least I don't think so.

    Right now there's a problem with even pumping the tyre up. I noticed the rear a bit flat after a break in riding for a bit, so I went to a servo to pump it up. Nope, wouldn't work. Thought the machine was farked. Went to a different servo and still didn't wanna inflate. I checked if my front tyre would inflate, and it did.

    Then I checked if my rear tyre would even deflate. It wouldn't.

    Are valves expensive to replace? Is it worth just getting a new rear tyre?
  2. Go to supercrap or similar, buy a packet of valves(usually 4? to a pack), and get the tool to change them, then you have spares.

    Should only cost $10 - 20 roughly....
  3. Carry it on your keyring forevermore. You'll know when to use it :twisted:.
  4. If it is the valve mechanism , then new valve insert should fix it. May even be the old one just needs tightening.

    However LizzyM's bike has developed a leak due to the valve itself not sealing in the wheel. This is going to require wheel removal and a new valve put in.
  5. If you can break the bead with "Tyre pliers" or something similar, there is no need to remove either the wheel or the tyre. There's enough room to remove and fit the valve stem if you push the tyre to one side.
  6. Oh wow, what a relief. Thought I'd be in a couple for a new tyre. I'll see if it works tomorrow, cheers all.
  7. I take it the existing tyre still has air in it? Like, it's not completely flat?

    The automatic pumps with the digital readout require a few psi to work. If the tyre is dead flat they don't 'know' they've been hooked up and just sit there. There's a 'flat tyre only' button on them for this exact purpose.

    If the tyre has been ridden dead flat for any distance, there's a pretty good chance that the tyre has rotated on the rim. If it has a tube, this will mean the valve will have torn off, and you'll need to replace the tube. Do NOT put one of those 'fix-a-flat' cans in it at this point, as it won't work. It will just make a very nasty mess inside the wheel that your mechanic is about to work on. He won't like you. If it's a tubeless tyre, you may have broken the bead, which means the tyre will need to be reset. It just means you have to get all of the wall in contact with the rim, all the way around on both sides at the same time. Otherwise, air goes in, air comes out ... no change.

    You could of course, try one of these.


    The ones I'm interested in are the first four.

    NOTE: I do NOT recommend this. I merely point it out.
  8. Thanks Kneedragon, the tyre isn't completely flat, I only noticed it whilst riding. It feel really soft over bumps and kind of 'rippley' in corners so I decided to check it out.

    It's a tubeless tyre. Actually it's a bit confusing, on the tyre walll says 'TUBELESS - on a tube tyre rim. Fit a tube'. Don't know what that's all about.

    So it's not fully deflated, so the automatic pump should have worked. I hooked it up to a little 12v air compressor pump at home and still nothing - would not read the PSI or anything.

    So it's tubeless - not fully flat - and possibly has a broken bead. Will this require a mechanic to fix? If the tools limited to a home job I'd like to have a crack at it.

    edit: if it was the bead, wouldn't the valve still somewhat work? It wont read ANY psi, inflate, or deflate. The tyre still has pressure.
  9. Basically it means that, if the wheel is not suitable for a tubeless tyre (most spoked rims for example) it is acceptable to put a tube in that particular tyre. For some tubeless tyres it is not (theoretically anyway; I've never had a problem).

    If it ain't fully flat, the bead ain't broken.

    Sounds like a valve issue, or, at least, an issue with the interface between the valve and the inflation devices you've tried. All I can suggest is to make sure the fitting is fully home on the valve stem so that the centre pin of the valve is depressed. If the pin isn't depressed, you won't get a pressure reading and the seal probably won't be good enough to force air in past the closed valve.
  10. So I took the valve out, unfortunately I dropped the end piece in the tyre. Whoopes. Looks like the wheel's coming off now.
  11. If there was a loose bit that could fall in, the valve was knackered.

    I wouldn't be inclined to faff with tyre removal for the sake of anything that could fall off a valve. I'd just screw in a new valve core and wait until tyre replacement time. That is, however, my personal opinion and not to be taken as a recommendation.
  12. So, you think the little bit of plastic in my tyre wont cause me any drama if I just revalve it and pump 'er up?

    I just took the tyre off, and I got quoted $30 for a rebead and new valve, but if I can avoid paying that I'd like to.

    It's not such a waste I took the tyre off I guess, I'm going to have to drive the tyre down to the servo to pump it up after a new valve is put in anyway.

    So repco/supercheap definitely have a valve I can just easily screw into the hole?

    edit: just a little question, the axle bar when I took off the tyre was very messy, so were the bearings. Should I clean them up and regrease them? if so with what would I grease them?
  13. Yes. Schraeder type valve cores are standard and have been for nigh on 100 years, which is pretty impressive really.

    I would consider it highly unlikely. I've not seen anything on any valve I've ever seen that I would regard as a problem in a tubeless tyre. Whatever it is, I doubt whether it weighs more than a fraction of a gram or has any sharp points. When you're moving it'll be firmly stuck to the inside of the tyre by centrifugal force so it won't rattle around to wear stuff away and something so light will have zero detectable effect on your wheel balance.

    Considering some of the crap I've found inside tyres (including the snapped off end of a cheapo tyre lever in a Land-Rover boot once, no wonder the bloody thing wouldn't balance :D), I'd definitely wait until tyre replacement time in this case. That, however, is what I would do, and I'm regularly berated on this forum for giving advice or indulging in behaviour that others consider dangerous.
  14. Start by replacing the valve core - for about $1.00. Then take it (by hand) down to the servo and pump it up. I'm not sure what sort of bike you have, so I won't suggest a pressure.

    NOTE: Don't ride it down there! Don't wheel it. Take the wheel off and carry it. If you roll that bike along, even a dozen metres, with a flat tyre, the tyre will turn on the rim and either rip the valve out of the tube, or unseat the bead from the rim. If you've come this far without messing either of those things up - don't stuff it up now!

    What the writing on the sidewall means, is that the tyre is suitable for tubeless use, if the wheel you're mounting it on is also suitable. In other words, a roadbike with a cast alloy wheel. (Or - less common - a dirtbike with a wire spoked wheel and a fancy pantsy rim that the spokes don't penetrate inside the tyre. BMW make some. I think if you had one, you'd know.)

    Tubeless valves look like this. The plain black rubber sort are by far the most common.

    Tube valves usually look like this.

    Note the valve-cap there. That's a good one, because it has that little screwdriver affair on the top. Turn that upside down, and you have a valve core tool. (A little awkward one, not a screwdriver one, but for a motorcycle that can actually be a good thing.) Also note the little space-ship looking thing under the valve cap, next to the lower nut. (B N1) That's a valve core. That's what you need to replace.

    The core is the same, whether it is a tubed or tubeless tyre. Buy it from a car place, not a push-bike place. Most treddlies now have car valves anyway, but older ones used to have a unique push-bike valve which was smaller and stupid, and cheaper to make. Not much chance but why take any chance on getting the wrong one?

    Car valve cores all look similar, but they don't look exactly the same because they're not exactly the same. Don't let that freak you out. They are a standardised part - in so much as they will all screw into any standard valve body and work.
  15. Don't bother buying the valve cores. Go to your nearest tyre service & just ask nicely if you can have one or two cores. I've worked in the industry for nearly 20 years & would be extreeeeeeemmly surprised if they wanted to charge you for a couple of valve cores.

    Another thing that is handy, however you may need to buy, is to ask if they have any metal valve caps from light truck or truck tubes. Benefit of this is they are a brass valve cap with a built in valve core tool. Fit them on the bike & you always have them available.

    If a bit of the valve fell into the tyre then the core must have been broken which will explain why it would not compress to take air.


  16. Exemplar help all guys, cheers.

    Kneedragon, thanks for the drawn out explanation, as I said I'd drive the tyre down to the servo as it's already off the bike (ready to be taken to the shop). Sucks that nobody was genuine enough to tell me it just needed a new valve when I called the shops.

    PatB, Cheers for the poticially (and legally) corrent answer :D

    Whitey, thanks for the cap advice. Seeing as I just called all the bike shops in my area and they basically all said it needed to be rebeaded, I think I'll just take my spare $2 down to repco and have a go there.
  17. e-e-e-r-r-r ... slow down a bit. I don't know that you only need a core. I don't know at the moment whether you have a tube in there or not. It may be that the core is faulty, or it may be something else. I think the core is most likely, and very cheap and easy to fix. If it turns out not to be that, then you might be looking at a tube. (Maybe $30.00. Less if you look around.) It may be tubeless and have a fault in the valve stem. Whitey might be able to change a tubeless valve without taking the tyre off, but I can't. (Well, not take it off, but I need to pop the bead and get in behind the valve hole, feed the top through and then get the pulling tool onto it.)

    Change the core first and see if that works.

    Repco may be able to help up to a point, but I'll make a guess here and say they don't have the right cones and clamps to suit a motorcycle wheel. Possibly they do, maybe not, but shop policy will usually be to tell the fool at the counter that you need a whole different type of tyre machine to do bikes, and they don't have one. That's bullshit. They don't like to do bikes because bike owners tend to be fussy, and the tricks and tips and corners you can cut are different between a bike and a car, so car tyre fitters often bugger up motorbike wheels and tyres - so car tyre shops usually have a policy of not touching them. The basic principle is the same, but the practice varies slightly in the details. And the wheel clamps and adapter cones are usually different, and if they have any bike ones, they may be mixed randomly in with all the others and you'd have to know which ones fit, or they may be out in the back room in a cardboard box marked Biological Waste - Do not look at! You'd be amazed how many tyre fitters ride bikes.
  18. The valve looks identitcal to the tubeless valve you pictured above. Plus the tyre says tubeless on it?

    Can't I just buy a new core and squish it through the open hole?
  19. Hang on a minute. I assumed what had fallen ito your tyre was part of the valve core, through the stem of the valve, after you'd unscrewed the core.

    From the above, I now take it that the whole valve body has pulled off and the rubber mushroom bit on the inside of the rim is what fell in, so you've now just got a hole in the rim. Am I right?

    If that's the case, take it to a bike tyre shop to get a new valve fitted to the rim. Yes, it'll cost $30 but it's worth it.
  20. As per PatB's post above it is sounding more like the entire rubber valve assembly has broken, not just the metal core inside the actual valve. In the valve picture a few posts up the valve will have broken near where the lower arrow for dimension "A" is. You would have had the top piece in you hand & the lower inside the tyre. If that is the case then your only course of action is to take it to the shop, break the bead & take out the rubber base & get a new valve fitted.


    FYI, $30 is not too bad a price considering you would pay similar for a car tyre to strip/valve/refit/balance anyway.