Originally Posted by
MarcusT
There are 3 measurements to consider in fork replacement. Length (wheel size), hub width and rake.
The rake is the distance the fork bends outward. Also called offset or forward. Even if your forks looks straight it will have rake, usually between 40mm-50mm
Hopefully, the rake is written somewhere on the fork. If not there are references online, how to measure rake. A few mms will not change handling a lot, but may be noticeable.
Of course, don't forget about brake placement and such.
oops, forgot to mention to ensure the steerer tube is compatible with your frame. Tube diameter, headset and axle type (quick release, thru axle)
Cheers
One more critical length. The length from the axle to the headset race length is part of the geometry that the frame designer designed the bike for. Ideally this should be the same distance, but a small difference of a few mm won't impair things too much. I am not a frame designer or builder, so I can't comment further. Maybe someone that knows this stuff better could comment on how a longer or shorter axle to crown race length changes things.
And one less critical number, width for tire. You would NOT want to get a fork that was designed for only skinny tire width if you wanted wider tires. One of my bikes maxes out at 28mm, I can't even fit a fender in that fork.