Constant flat tyres because of valve ripping

Sopor81
Sopor81 Posts: 3
edited April 2013 in MTB workshop & tech
Hi all,

lately I've been having a lot of flat tyres. I put in a new tube, yes I am sure I have the right size 26 x 1.95, and when I start riding the valve will after a while stand on a slant, just like my tube has been moving. I pumped my tyre to the maximum, tried less pressure as well but because of the valve being on a slant, the borders of the hole where the valve goes through cut a whole in my tyre (at the valve). Any of you know what's going on? How do I prevent the valve going on a slant?

Comments

  • nicklouse
    nicklouse Posts: 50,675
    what rims are they? and what tubes are you using.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • mcnultycop
    mcnultycop Posts: 2,143
    And what valve type?
    Nerve AM 7.0
    Scandal
    Felt Roadie
  • Lagrange
    Lagrange Posts: 652
    Because there are two types of valve with different diameters then ther are two options for the diameter of the rim. If you have the thin presta valve in a Schader diameter rim aperture then that could allow for different tension from the tubes on either side of the valve to cant it over. Way round it when putting the tube on is - valve in first and work the tube in evenly on either side of the tube at the same time. Also - if the valve has a lock nut - to hold it firmly on the rim then use it after the tyre is on - sometimes if the tyre is tight then you need the valve to be loose to get it on. As you are putting the tyre on ensure that there is some pressure in the tube. Check that the tube is specifies for the tyre width you are using.
  • njee20
    njee20 Posts: 9,613
    I'd look at your rim tape - a new one may well stop the tyre rotating (and dragging the tube round) and tearing. A bit of talc in the tyre can stop the tube sticking too, deals with the problem not the cause though.
  • Sopor81
    Sopor81 Posts: 3
    Thanks for all the replies and tips. I have the Specialized Hardrock sport disc 2012 which suited me fine for the dirt track to and from work (9 miles). The valves are Schrader valves without lock nut, I've tried cheap Halfords tubes, expensive Specialized tubes and even Slime ones but nothing helps. I've also changed the pressure in the tubes but still getting flats.

    The tyres are not the original ones, went for some Armadillo ones to prevent punctures from thorns but I think they are not the problem as they worked fine for 6 months.

    Any more tips? Would a new rim tape help or shall I use some blue tack to keep the tube in place ;-) ?
  • Chunkers1980
    Chunkers1980 Posts: 8,035
    Check for burrs and roughness around the hole. No to blu tack though!
  • nicklouse
    nicklouse Posts: 50,675
    use the lock nut.

    also mark the tyre and the rim. to see if the tyre is slipping.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown

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