Your steer tube is 1 ⅛. The tricky part is finding a fork that will approximate the fork length of the suspension fork you’re replacing and has the brake mounts you need. If you don’t get a fork with a similar over all length, a standard 26” front fork will be too short. Way too short. Your front end will be too low, head angle too steep and bottom bracket too low. Your seat tube angle will also get a bit steeper too. Measure the axle-to-crown and try to find something close. It doesn’t have to be exact. You have a better chance at winning the lottery than finding an exact matching length rigid fork for a 1998 Stumpjumper. The angles on those old MTBs are pretty slack, so if you find something that comes up only a little short it might be close enough.


-Kedosto