Rear wheel flex when climbing

markiegrim
markiegrim Posts: 136
in Road beginners
Never had this issue with my old alu trek and alloy fulcrum Quattro wheels (1800 g) but recently got a titanium bike with Hunt Aero Race Wide wheels

When I get out of saddle on a climb of 13%+ the rear wheel flexes laterally to the point where the brake rubs on the rim

Is this just to be expected of lightweight alloy wheels?

Wheel is 1498 g. I am 66 kg

Bit of Backstory: wheel was previously even flexier to the point where it was flexing at hub as well as rim. But I resolved that after calling Hunt and they talked me through taking hub apart, reassembling and refitting wheel. I don’t think that issue is relevant now but thought I’d mention it.

All advice and shared experiences welcome

Thanks

Comments

  • zest28
    zest28 Posts: 403
    1500g for an alloy wheel is light. So I am not suprised if it flexes.

    Upgrade to some nice carbon wheels which should be much stiffer.
  • pblakeney
    pblakeney Posts: 27,490
    I have 20kgs on you and any increase in wheel weight will be at the hub.
    Sounds like a badly made wheel.
    The above may be fact, or fiction, I may be serious, I may be jesting.
    I am not sure. You have no chance.
    Veronese68 wrote:
    PB is the most sensible person on here.
  • tonysj
    tonysj Posts: 391
    Im 76kg and have been using CERO EVO AR24 wheels for a couple of years and have never experienced rim brake rub or flex and they are reported to be sub 1500gr wheels on the website. No experience of Hunts though.
  • whyamihere
    whyamihere Posts: 7,716
    Rubbing at the brake is actually more likely with a stiffer rim is if the build is poor. Think about the geometry - You can assume the hub is fixed (unless there's frame flex or a bad hub involved), so the rubbing on the brake is because the rim has effectively pivoted around the hub. If the rim was flexy, it would flex at the bottom where the weight is being applied, but because the rim is stiff, it translates the movement up to the top of the wheel and causes it to rub on the brakes.

    It could be caused by poor hub geometry, the wrong spokes for the application or simply a bad build, but the one thing that's not likely to be at fault is a flexy rim.

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