Can I put 27.5" wheels in a 29er frame?
By Crankworthy · Published · Updated
It will usually fit, but it changes the bike. The smaller wheel lowers the bottom bracket, making pedal strikes more likely, and slightly alters the geometry. Disc brakes still work; rim brakes will not line up with the smaller rim.
Why
A 27.5" wheel has a smaller outside diameter than a 29", so the whole bike sits lower. The bottom bracket drops, and pedals and cranks get closer to rocks and roots.
Disc brakes are unaffected, because the rotor is mounted at the hub. Rim brakes are set for the 29" rim and cannot reach down to a smaller one.
Many riders make this swap to run a plus-size 27.5" tyre, which is wide enough that its outside diameter ends up close to a regular 29er's — restoring most of the lost height.