Rear QR levers and spinning of wheel

mickisup
mickisup Posts: 295
edited October 2015 in Workshop
I am noting that with one of my bikes that tightening the rear QR by various degrees alters considerably the time the wheel with spins. Using a baseline of one full revolution of the crank, in same gear, I can vary the wheel spinning duration from 6 seconds to 30 seconds by having the QR at different degrees of tightness.

Should this make such a difference, the bike (cyclocross) has been noted as being slow to get back up speed.

Does this sound like a wheel problem or something else, and is there a right and wrong tension on the QR?

Comments

  • Rightarmbad
    Rightarmbad Posts: 216
    The QR pressure is being added to the bearing preload.
    Cheaper wheels suffer more from this problem than better ones.
    loosen off the preload on the wheels until there is a tiny bit of play and test fit to see if it just goes away with the QR at an acceptable tightness.
    If not, keep playing until you find the perfect amount of play that disappears when the QR is done up.
    Or go buy some better wheels......
  • mickisup
    mickisup Posts: 295
    :shock: thanks for the information. I will also see whether I can help by backing off the QR a little to see what the differences are in actual riding, it never occurred to me until yesterday that this mattered so much, it would appear that riding with the QR done up very tight is using more energy than is necessary as the wheel spins less freely!
  • desweller
    desweller Posts: 5,175
    You can't accurately assess the performance of the bearing with no weight on the bike. When your weight is on the bike the bearing races and rolling elements will all deform; the running condition of the bearing will be different to how it is with no load on it.
    - - - - - - - - - -
    On Strava.{/url}
  • keef66
    keef66 Posts: 13,123
    You shouldn't really be adjusting the tightness of the QR clamping to compensate for badly adjusted bearings. Adjust the bearings so that the properly clamped QR just eliminates play but still allows the wheel to spin. If tightening the QR is inducing too much drag in the bearings it suggests they are overloaded and will likely fail prematurely.
  • keezx
    keezx Posts: 1,322
    [url=http://www.bikeradar.com/forums/viewtopic.php?p=19721111#p19721111]Rightarmbad[/url] wrote:
    The QR pressure is being added to the bearing preload.
    Cheaper wheels suffer more from this problem than better ones.
    l

    Cheaper wheels will have steel axles and suffer LESS fom compression.

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