I have a pretty cheap bike (29" Genesis Two-Nine) which served me very well for 2 years and now the front wheel got stolen.

Are front wheels universally replaceable and if yes, what are properties which must be equal? For example, my bike had a 29" mountain bike front wheel with a disk brake. Will any wheel with these properties match the bike?

2 Answers 2


There are 3 things to worry about and you've covered two.

  1. Size, the wheel rim should match the current size.

  2. Brake compatibility, if you have disc brakes you need a compatible hub, could be 6 bolt or centerlock. It has to be compatible with the rotor you will also purchase. If you have rim brakes you would purchase a rim brake compatible rim. (you can use a disc hub on a rim brake).

  3. Axle compatibility, there are current at 4 main axle widths and lengths 9x100mm QR, 15x100mm thru axle QR, 20x110 thru axle and now 15x110 thru axle. You need to select the hub that is compatible with your fork. A 15x100mm wheel can work on a 9x100mm fork with the use of a shim.


For a front wheel you need to match size (29") and width (not critical - look at similar tire size), hub (Being cheap its probably 9mmQR but there is also 15mmQR and 20mmQR) and rotor size.

The rotor size was probably 160mm, but may have been 180mm (They don't give it in the specs). If you end up with the wrong size on the wheel, its easy to change the rotor or get an adaptor for the disc calliper. Have a look at the calliper on the front fork - if its mounted on an adaptor the adaptor should have a disc size printed on it (and if not, likely a 180mm rotor). If there's no adaptor, its most likely a 160mm rotor.

  • Can't one just measure from the axle center to the top of the slot in the caliper, less a couple of mm?
    – andy256
    Apr 20, 2015 at 23:10
  • That would work, but its too easy. :)
    – mattnz
    Apr 21, 2015 at 2:41

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