Building a fixie with an old Norco frame with Tange 900 double-butted tubing.
The bike was made for 27 inch wheels, but I was planning on spreading the mounts to fit 700C's.
The fork weighs a damn ton and am hoping to replace it, but two things concern me:
1. It is one of the curved style forks common on old road bikes, in considering a new fork should I look for one that is the same style, or does that affect the bike?
2. Can I make use of a 700C fork without real detriment to the ride-ability of the bike? I'm worried that an alteration in the size of the fork will offset angle with the rear wheel.
If I'm going with a new fork, I may or may not switch the headset to threadless. It is a 1 inch steer tube... so given that... should I switchover to threadless... or just get a lighter quill stem and threaded fork?
What do you mean by spreading the mounts to fit 700c???
Take it to a bike shop that has older bikes. Find a oldest most-haggard looking mechanic there. Ask him if he has a 700c fork that would match the rake of your old 27" fork. He should be able to help find you a fork with the closest crown to axle measurement so it doesn't affect handling so much. Chances are it's going to be just as heavy as your old fork if it is steel. Maybe a shop near you would have some carbon or aluminum forks with 1in columns. If you find a nice light fork that would work and it is threadless, I'd convert to threadless. If not, stick with a threaded fork.
Look out for Lemond forks from the late 90s. Some have an icon logo. They are carbon with an aluminum steerer and are threaded. Fairly light. May or may not work for your frame geometry wise.
So, should I find a 700C fork that matches the rake of my old fork, then the difference in length of the fork(s) won't cause problems? Wouldn't there still be about an inch of difference between the rear and the front?
You still need to worry about the crown to axle measurement to closely match your old fork. so yeah, the difference in length matters a bit. But a slight difference isn't going to be a huge deal. Chances are it will just make your head tube angle steeper and you'll get faster, more responsive handling (some people say twitchy). This could be a plus or negative. If your frame wasn't a pure race bike or track bike, chances are the headset angle isn't all that steep to begin with so this shouldn't be a big issue.
Head Angle of 73 degrees is considered ideal for some builders. 72 or 74 degrees is perfectly acceptable. You will notice a difference if you go from say 73 to 75 degrees or 73 to 71. This is for road bike geometry. Mountain bike geometry is a more relaxed to add stability.