chopper2

I recently bought a Trek 8.3 DS and the lockout mechanism on the fork started acting funny. I keep it locked all the time and would rather have a rigid fork. What rigid fork would be a good replacement with the same geometry and still work with disk brakes?

Bianchigirll 

Welcome to the forums. There are lots of good forks out there and any difference in rake and trail will be negligable.

Just be sure your new fork is suspension corrected

Check nashbar, ebikestop and niagara they all have great parts and should have a fork to suit your needs.

This nashbar bar is 'suspension corrected' https://www.nashbar.com/bikes/Product...0052_174928_-1___

This one is corrected too. https://www.ebikestop.com/dimension_m...ack-FK1266.php

How recently did you buy your trek? did you buy it new? If the fork is defective your shop may be able to get you a rigid fork from trek.

chopper2

So I take it my bike has a threadless fork? Will my disk brakes work with any fork designed for disk brakes? Is it tough to remove/install a fork? Sorry for the dumb questions, I've just never disassembled that part of a bike before.

DannoXYZ 

Yes, but the semi-integrated headset will limit your headset replacement options.

As long as you get a replacement fork with the same brake-caliper mounts, it will work. There are some common disc-brake mounting standards: two flavours of IS and post-mount (along with a smattering of other not-so-common mounts). Check out this site: Shimano Framebuilder Info to see what exact type you have. And get a replacement fork with that same disc-brake mounting method.

Not really, I've done it on the side of the trail with tools you can carry in your pocket. Check out this Park Tool - threadless headset service guide. Make sure you lay out the parts removed in a specific order so you can get it all back together in the correct sequence. Good luck!

jimc101

Why would the OP need to replace the headset? if just changing the fork, only the crown race needs to be swapped between forks.

For brakes, the bike the OP has has only been in productions for 2 model years (2012 & 2013) so will not have any obsolete brake mounts. All modern discs are Post Mount, and have adaptors for IS. IS as a dedicated mount (i.e. the brake will only for this has been obsolete for several years now).

For fitting a fork, the biggest issues are swapping the crown race correctly and installing the Star Fangled Nut correctly, if the OP doesn't have the tools / experience, these are probably better left to a bike shop, and if the OP buys a fork from one, could get these fitted / the steerer cut to size when purchasing.

As Bianchgirll, would be looking at getting the fork checked by a Trek dealer initially; before spending any money on it, as if the fork is defective, it should be a warranty issue.

FBinNY 

The key dimension in a suspension corrected fork, is the crown to axle distance. When you measure yours be sure to use the loaded dimension for your fork, which occurs when you're sitting on the bike in riding position. Then either lock the fork there so you can measure off the bike, or have a friend measure for you while you're on the bike.

Odds are you won't match this perfectly, so go for the nearest match. If you're in the middle between 2 choices, let handlebar height decide. If you're near the top of the bar height, or have lots of spacers under the stem, go long to raise the bar a bit, or if you have no spacers, and want a lower bar, go shorter.