Wheel wobble?

Schoie81
Schoie81 Posts: 749
edited June 2013 in MTB workshop & tech
Hi guys,

Spent the last few days giving my MTB its first proper clean (it was well overdue and I promise never to let it get in that state again!) Anyway, I was fiddling with the gears to get them running nice and cleanly and I noticed the rear wheel seems to be out of balance somehow. Spinning the wheel (fast) whilst off the ground theres a noticeable up and down movement to the bike as the wheel spins. Its spinning true - no side-to-side movement, but definitely something doesn't seem right. Problem is, I can't feel it when I'm riding it, so firstly, I've no idea whether it did it before I took the wheel off to clean it, or if it could be because i've not put the wheel back on quite right somehow. I released the wheel again and reinstalled it and it still does it.

Could it just be a balance thing, maybe even just the weight of the valve as it goes around, or just a variation in the tyre/tube? Is it something I should worry about?? As I say, with my 80kg on the saddle, I can't feel anything whlist riding....
"I look pretty young, but I'm just back-dated"

Comments

  • pesky_jones
    pesky_jones Posts: 2,890
    Could just be the tyre, how much vertical movement are we talking.
  • The Rookie
    The Rookie Posts: 27,812
    Either the wheel is egged (that is the rim isn't a constance distance from the hub round the hole circumference) or - more likely - the tyre isn't perfect, remove tyre, put wheel back in and bluetack a ruler across the stays and see if the wheel is egged (or just do it by eye, an assistant to hold the bike helps here!)
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • Schoie81
    Schoie81 Posts: 749
    Its difficult to say how much - I was holding the rear wheel off the ground, so the amount the bike moves depends upon how much i resist its movement with my arms. I don't think i'd be able to physically prevent it moving though if I attempted to.

    Will try taking the tyre off and checking the rim as you suggest.

    I don't know if its relevant but the bike is a hardtail, its almost two years old, i've had it from new and i've never noticed anything feel odd when riding it. I've never had a fall on it and it hasn't been subjected to a lot of big impacts on rocks etc...
    "I look pretty young, but I'm just back-dated"
  • shadow4532
    shadow4532 Posts: 133
    sounds like a balancing problem i.e. one side of the wheel weighs more than the other. but in any case it doesnt really matter on a bike. and you probably wont notice it on the trail. :)
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  • Schoie81
    Schoie81 Posts: 749
    shadow4532 wrote:
    sounds like a balancing problem i.e. one side of the wheel weighs more than the other. but in any case it doesnt really matter on a bike. and you probably wont notice it on the trail. :)

    Yeah, I did wonder if it was similar to a car tyre where they add weights to the rim to balance it out, but you only really notice an out of balance tyre when you're doing a fair speed - not something I need to worry about on my bike!! As I say, its either a new problem, or its not noticable when I'm riding.

    Will be out on it on a proper ride tomorrow so I'll a) take it steady to begin with, in case something is wrong, and then b) see if I can feel it when riding.
    "I look pretty young, but I'm just back-dated"
  • Chunkers1980
    Chunkers1980 Posts: 8,035
    Schoie81 wrote:
    Problem is, I can't feel it when I'm riding it

    That indicates to me that there is no problem.
  • Schoie81
    Schoie81 Posts: 749
    Schoie81 wrote:
    Problem is, I can't feel it when I'm riding it

    That indicates to me that there is no problem.

    Done 22miles on it today and couldn't feel anything untoward. The rear tyre is about ready for replacement, so when I change it i'll check the wheel is round, but I'm not going to worry about it too much...
    "I look pretty young, but I'm just back-dated"