Originally Posted by
seeker333
You also must consider the fork's length. Swapping a fork in to a bike that is of improper length will change HTA, STA, BB drop, can cause pedal strike and ultimately affects how the bike steers and handles. The critical fork length dimension I refer to here is normally called "axle to crown" (ATC) distance.
If this fork is for a Ritchey Breakaway Cross, and the
linked geometry chart is correct, then you ideally want a fork with a 390mm ATC. You can usually go +/- 5mm without noticing a difference from the original fork; more than that, you begin to notice the effect of the geometry changes you've made with an improperly sized fork.
The closest touring fork that I know to be near 390mm is the LHT 700c fork @ 390mm - basically a perfect choice. The Cross Check is a bit too long @ 400mm. Space Horse @ 395mm could work. LHT is likely your best bet.
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I am in the final stages of building up a bike, the frame manufacturer sold a fork with a 400 mm axle to crown length. Instead I put on a 2004 LHT 700c fork that I had instead of buying their fork. I assumed that the length of my LHT fork was close enough.
I found handling to be quite good with the LHT fork on a frame designed for 400 mm fork. That said, I have not yet put a load on the bike, have 30 some miles on it unladen so far. I am running 37 mm wide tires.
Maybe since the LHT is a high trail bike, using the LHT fork on a frame designed for a fork 10 mm longer reduced the trail slightly to make the fork have a more neutral trail?
But, I do concur that you want to have a measurement that is quite close to what the frame designer had in mind.