New fork?
 

I've got a Nishiki Colorado mountain bike with a suspension fork...the fork doesn't hold air, and one of the canti studs has been broken off into the mount, with no way of getting it out (it dulled and then blued a diamond tipped drill bit). As a result, I'm looking to go with a new fork, that is preferably cheaper. I'm looking right now at the Tange cromoly forks (~$40), and the cheaper, hi-ten Sun forks (~$20). How much fudge factor can you assume when screwing down the threaded headset? Can it be a little short and still work? My biggest concern is getting one that is way too long. There's no way to put spacers on it to allow it to be screwed down, is there? What would you guys recommend? I don't have the bike with me right now, but it's a 21" frame. Not sure of the head length, but the forks that I've found don't really come in many different steer tube lengths.

Also, 1" is what I'd need, right? It's got a standard quill stem, so I'm doubting 1-1/8"...

Too short is bad, I think. Too long is good, in that you can always have it cut to size and re-threaded.

Does the bike have a quill stem now?

You now have a donor bike. For the cost of changing that fork out, you should be able to find a decent MTB used. 21 inch is a pretty big MTB.

This is why I wanted to use this bike - it fits me rather well. The reason I wanted to keep this particular bike is that it'd be hard to find a larger MTB in the shape that this one is in (nearly scratch free, mechanically sound) for $40 (the original cost) plus another $30 for a new fork. Makes me sad...

Assuming the bike was originally designed for a suspension fork, a replacement fork should be suspension-corrected to keep the original geometery.

I know what you mean about finding larger MTBs. Just bought younger son a 21" '91 Diamond Back Topanga that needed tires and some lubing and adjustment but no other parts and paid $120 for it. I probably overpaid but they do not come up around here very often.

It was originally designed for a suspension fork, but judging from the original geometry and the riding geometry (rode it around with just the back brake for 10ish miles) on the saggy fork, riding one with a rigid fork would be suitable. I was primarily curious as to how one would go about setting up a bike with a new fork, given a certain head tube length. What ratio would one need for a replacement fork as far as steer tube length vs. head tube length?

I have a used tange chrome MTB fork that I'd be willing to give you, Matt. Depends on how long a steer tube you need? If you can measure I can let you know if mine is long enough.

Holy crap, you're my hero! I'll measure the original fork tomorrow and let you know. Thanks!

of course I'm 'Mr. Bent Fork' on C&V, so be forewarned : )

Don, I measured it, and it appears to be about 6-3/4" steerer...

I measured the fork and it's approximately 8 1/4" from the bottom of the crown race to the top of the steer tube, with about 2" of thread. I'll bring it to Indiana this weekend. Will double check if it's 1" or 1 1/8".

Sounds good! I won't be in town this weekend, but will next, and hope to get off (I'm working in the Uniform dept. at the Academy for registration. If not, I can ask my dad to swing by. Thanks again!