Today, I replaced the fork on my bike with a much lighter, less heavy-duty Tange Cr-Mo fork that came off a mid-eighties Schwinn frame I just bought (for 20 bucks, bottom bracket and headset included too!):
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Here's the old fork, a nice chrome piece also manufactured by Tange, but unfortunately made for 27 inch wheels.
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And the finished product, in artistic black and white:
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The biggest reason I did all this today is shown below. My brakes (and I know, the cable's frayed and there aren't even any washers on the pads, a big no-no, but it's a fixie, give me a break) work fine, at least as much as I need them to, with the old chrome fork. But if I'm not careful and let one of the arms on the caliper get loose, there's not a lot of clearance between the pads and the tire sidewall. I flatted a few weeks ago this way going down a hill. Coming to a safe stop on a 20% incline after that isn't a pleasant experience, but neither is patching a tube and putting electrical tape around a ripped tire for the ride home in ten degree weather.
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You can tell from the photo that mounting those brakes on the right fork really gave me plenty of room to make good contact with the rim. I should've either done something like this or ordered long-reach brakes a long time ago, because the stopping power is incredible, even on my non-machined rims--enough to endo if I'm not careful. There are plenty of other benefits too, since I saved a significant amount of weight, made my frame clearances and wheelbase a lot tighter for more responsive handling, and now have eyelets on the front for when I choose to mount my full fenders.
Lesson learned: it's worth having the right tools for the job.