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Questions about converting from a suspension to a rigid fork

So i bought a Trek 820 at a yard sale this past weekend for $20. Its a 2002 so it comes with what looks to me like a crappy suspension fork. id like to swap that out for a rigid fork with rack/fender mounts on it. I've seen the term 'suspension corrected' tossed around and was wondering what what the ramifications are of doing such a job. I'd like the bike to handle well when loaded, but also perform ok on singletrack. does anyone have any suggestions on doing a swap like this? Would one of Kraynick's Schwinn forks do the job?


floggingdavy
2011-06-03 20:34:42

Kraynick's Schwinn forks won't do it. They're short, and I'd imagine the bike you have is 1 1/8" threadless whereas most of Gerry's forks are 1" threaded. He may have the fork you need however... read on.


You need a fork with the same or similar axle to crown race measurement and rake. Rake is more than likely the same across any model you're going to readily find, axle to crown differs quite a bit between forks. "Suspension corrected" simply refers to a rigid fork that is longer than it the minimum length it needs to be to fit the given tire size, which was the length of most mountain bike forks pre-suspension.


You probably want a rigid mountain fork with an axle to crown spec of about 410mm. Think Surly 1x1, Kona Project 2, etc in the aftermarket realm. Ask around enough and someone surely has something that will work just hanging around.


bradq
2011-06-03 21:06:14

I’m not sure but I don’t believe you need to worry about converting from a suspension fork to a rigid. It’s when you convert from a rigid fork with a rake to a straight suspension fork without a rake that you need to check the front wheel clearance.


Edit - If it’s a suspension fork it’s most likely a 1 1/8 fork and all the old Shwinn stuff is 1 inch and won't fit


greasefoot
2011-06-03 21:06:24

All forks have rake, or offset, between the steering axis and the front axle. It is achieved through a curved fork blade, forward mounted dropouts, or an angle less than 180 between the fork blades and the steerer tube as measured form the front of the plane of the headtube. One, two or all three ways may apply on a given fork.


Most all 26" mountain forks (suspension and rigid) have 45mm of offset.


bradq
2011-06-03 21:09:01

Brad you are right. I guess it would be easier to suggest something if we could see the bike in question.


greasefoot
2011-06-03 21:17:41

thanks guys, im gonna have to pay Gerry a visit and see what hes got laying around. and thanks again, Brad, for some numbers. It's def a 1 1/8" fork. i was looking at the kona projects. my only problem is the cost. i did get the bike for a deal, but something about putting an $80 part on a $20 bike makes me second guess the decision. Although, its not like putting a Rohloff on a Huffy...


floggingdavy
2011-06-03 22:16:30