Splitting Inner Tubes

supers
supers Posts: 33
edited July 2017 in Workshop
Have just fitted tyres and inner tubes (conti) to my new wheels. On pumping the back wheel, the tube split at around 40 PSI, just above the valve. Tried to the pump the front one, same happened.

The wheels are Zonda C17, so don't need rim tape and I was using a floor pump.

Any ideas?

Comments

  • shortfall
    shortfall Posts: 3,288
    Pinched between the rim and tyre? Duff tube?
  • bondurant
    bondurant Posts: 858
    Either you are massively unlucky or the tubes were pinched as Shortfall says.

    Push the valve into the tyre as you are seating it to get the tube into the tyre and away from the rim. Also partially inflate the tube once both sides of the tyre are on the rim and check that the tube isn't caught before inflating properly.
  • froze
    froze Posts: 203
    Where the splits along a seam? or at the junction of the stem and tube called the weld?

    When you're pumping the tire do you keep slack in the hose? the valve shouldn't be moving at all while pumping.

    Check to make sure there are no burrs around the valve opening in the rim. Then try using talic on the tube so it can slide easier inside the rim. Or quite possibly you got a batch of crappy tubes that were flawed, try a different brand.

    Pinch thing is possible but odd considering you would put the stem area of the tire on first and work your around to the opposite side, thus the pinch would more than likely happen at the very last section of tire being put on. So I'm having some trouble with that idea.
  • pilot_pete
    pilot_pete Posts: 2,120
    froze wrote:
    Pinch thing is possible but odd considering you would put the stem area of the tire on first and work your around to the opposite side, thus the pinch would more than likely happen at the very last section of tire being put on. So I'm having some trouble with that idea.

    Not sure the technique described is a given - I've seen many variations including finishing putting the tyre on at the valve as it allows the opposite side of the tyre beads to sit in the well of the rim.

    Mind you, I did see a fellow club rider burst two tubes whilst repairing a flat - I watched him more closely on the third attempt and pointed out that the tyre needed to be seated at the valve as he was not pushing the valve in as you describe and getting the beads seated before giving it the beans with his pump! :roll: This from someone who had been riding for years...

    Does sound like the most likely cause is pinching the last bit of tube between tyre bead and rim, which can be easily done without due care and diligence, and then inflating with that section of tube not contained by the tyre.

    PP

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