Wheel size – check your tyre sidewall for 29" or 27.5". Mixed-wheel ("mullet") bikes run a 29" front and a 27.5" rear.
Riding style – XC wheels prioritise low weight. Trail and all-mountain wheels balance weight and strength. Enduro and freeride wheels use stronger rims and spokes for big hits. E-MTB wheels (such as the DT Swiss H and HX range) are built for the extra weight and torque of an e-bike.
Axle – most modern MTBs use Boost spacing: 15x110mm front and 12x148mm rear. Check your fork and frame before ordering.
Rotor mount – choose 6-bolt or Centrelock to match your rotors, or use an adapter.
Freehub – match the rear freehub to your cassette: Shimano Micro Spline, SRAM XD or Shimano/SRAM HG.
Internal rim width – around 25mm suits XC tyres, while 30mm and wider suits trail and enduro tyres.