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Wobbly tyres

rubezrubez Posts: 323
edited May 2014 in MTB workshop & tech
What causes wobbly tyres? (when you spin them, bike upside down) and the wheel itself is fine and doesn't waver.

Posts

  • stubsstubs Posts: 5,001
    The tyre might not be seated properly. Let it down make sure it is straight on the rim and then pump it up to about 50psi.
    Fig rolls: proof that god loves cyclists and that she wants us to do another lap
  • rubezrubez Posts: 323
    By seated you mean?

    I'm thinking I should be pumping it up slowly, massaging the tyre as I go? Making sure it goes on evenly... this isn't standard practice though, is it?
  • cooldadcooldad Posts: 32,601
    Some people enjoy massaging wobbly rubber things.
    I don't do smileys.

    There is no secret ingredient - Kung Fu Panda

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    Parktools
  • Chunkers1980Chunkers1980 Posts: 8,035
    Jelly
  • rubezrubez Posts: 323
    I'm guessing this may be a side effect of the way the tyres were packed for shipping (doubled up on theirselves, in a figure 8, to save space)

    You could see they were a bit out of shape, I thought once the tyres were pumped up, that would iron out the wrinkles...
  • The RookieThe Rookie Posts: 27,748
    Lots of things, from cheap shite tyres with poor manufacturing, steel bead ones that have been folded at the bead and need straightening to poor fitment.

    Given yours were flipped for shipping you need to check with the tyre off that the bead hasn't been kinked and straighten if it has, if not if it's a bend in it can cause a puncture by chafing the tube anyway.
  • rubezrubez Posts: 323
    What is the bead, the inner lip?

    I heard talc powder helps get the tye even when fitting, so I'll try that too.
  • cooldadcooldad Posts: 32,601
    I believe Parktools might have some info on tyres. Even mentions bead, maybe.
    I don't do smileys.

    There is no secret ingredient - Kung Fu Panda

    London Calling on Facebook

    Parktools
  • stubsstubs Posts: 5,001
    rubez wrote:
    By seated you mean?

    I'm thinking I should be pumping it up slowly, massaging the tyre as I go? Making sure it goes on evenly... this isn't standard practice though, is it?

    Seated means the tyre bead( the rim of the tyre) is sitting straight into the wheel rim. The wheel rim will be a clincher it has a hook that grips the tyre bead but sometimes the tyre bead is deformed or the inner tube/rim tape is caught and stops the bead going in.
    Fig rolls: proof that god loves cyclists and that she wants us to do another lap
  • cooldadcooldad Posts: 32,601
    Bang it up to 60psi or so. For that you would use a bicycle pump. Once seated let some air out. Using the valve.
    I don't do smileys.

    There is no secret ingredient - Kung Fu Panda

    London Calling on Facebook

    Parktools
  • The RookieThe Rookie Posts: 27,748
    The bead is the reinforced part that forms each 'edge' of the tyre before get to the gap between the two sides.

    You good try using Google a bit rather than asking dumbass questions, or overcome your phobia and try Parktools.
  • JBAJBA Posts: 2,749
    A picture speaks a thousand words, rubez.
    Post a couple of piccies so people can see what you're talking about and maybe offer meaningful advice. :)
    “Life has been unfaithful
    And it all promised so so much”

    Giant Trance 2 27.5 2016 ¦ Sonder Broken Road 2021¦ Giant Revolt Advanced 2 2019 ¦ Giant Anthem 3 2015 ¦ Specialized Myka Comp FSR 2009
  • cooldadcooldad Posts: 32,601
    JBA wrote:
    A picture speaks a thousand words, rubez.
    Post a couple of piccies so people can see what you're talking about and maybe offer meaningful advice. :)
    You must be new.
    I don't do smileys.

    There is no secret ingredient - Kung Fu Panda

    London Calling on Facebook

    Parktools
  • BigAlBigAl Posts: 3,122
    cooldad wrote:
    Once seated let some air out.

    That sometimes happens when I sit down. I blame my age (or Wiggle)
  • rubezrubez Posts: 323
    I have invested in a floor pump with pressure gauge, should help me better than that mini handheld affair.

    Haven't used the new pump yet, but I can sort of see the problem why the tyres are wobbly...

    My tyres have crosshatching all round, and 2 parallel lines going round them... I can see that these lines are flush all the way round when pumped up, except for one little section where it dips below, into the rim - and so the tyre is out of whack.

    What may be the reason for the parallel lines not staying flush to the rim all the way round?!

    It seems to happen on both wheels...

    Max pressure on the Magic Mary tyre seems to be 50 PSI.

    The tube is Continental MTB 26 Tube 26", 1.75 - 2.5", 60mm Valve, Presta,

    Any ideas?
  • The RookieThe Rookie Posts: 27,748
    The tube just stops air leaks, it has no structural strength.

    I would dismount the tyre and rotate round the rim a bit, check no kinks in the bead and refit.
  • rubezrubez Posts: 323
    The tube just stops air leaks, it has no structural strength.
    What does that mean?

    I have refitted the tyres a few times (tried talcum powder also), still the same problem on both wheels. Surely there must be a specific reason for this to happen consistently?

    I just need the 2 parallel lines to pop out at one little section (they dip down below the rim for about 2-3cm) and the entire tyre would be flush, and without wobble, presumably...

    Don't know what PSI I was pumping to with the little pump, but the tyres were pretty solid.

    Will pump up to 50 PSI next time.

    Does my tube specs sound OK?
  • The RookieThe Rookie Posts: 27,748
    rubez wrote:
    The tube just stops air leaks, it has no structural strength.
    What does that mean?
    It means the tube conforms to the shape created by tyre and wheel, so is irrelevant in any discussion here, it has no effect on safe pressures either.
  • YateleyChapYateleyChap Posts: 24
    rubez wrote:
    What causes wobbly tyres? (when you spin them, bike upside down) and the wheel itself is fine and doesn't waver.

    Something similar happened to me and on closer inspection it turned out to be a knackered tyre sidewall (at the area closest to the rim). The tyre was bulging slightly along this weakened section, so when spinning and viewed from above it appeared as though the wheel needed truing. Those tyres got promptly put in the bin.
  • it means the bead on the tyre hasnt seated into the seat of the rim..

    run some fairy liquid round the bead and the seat, and then whack it up to 50/60 psi..

    all should sit in..


    if it fails... give up
  • rubezrubez Posts: 323
    Aw yiss... both tyres seated, and sitting pretty @ 30psi, ready to roll.

    Just waiting on a new derailleur and I have to set up front and rear gears and thats me done :lol:

    Got two spare Chainreaction £10-off codes if anyone wants, they are only valid for a few more days probably. Don't think they are tied to my account.
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