Thursday, October 21, 2010

Unconventional Headset Build

I recently picked up a chrome Klein 700C fork for Juliana's to-be 650B Schwinn, both to reduce the pink factor and to make the front brake reach situation a little more manageable than with the bike's original fork, which had very long legs (designed, as it was, for 27" wheels).  Something I didn't really anticipate is that this fork would create some complications from a headset perspective.

I was surprised to find that the steerer tube of the fork is fully chromed.  And on this fork, the threads stop about an inch and a half short of where they need to be for Juli's frame.  I think if I took the fork to a bike shop that has the tools needed to thread the fork down, they'd refuse to do it because the chrome plating would be hard on the threading die.  Also, the unthreaded length of the steerer is a little too short to support both a brake cable hanger (which I need because I'm going to install centerpull brakes on the bike) and a threadless stem, without having to clamp the stem onto a partly threaded area, which seems like a really bad idea.  And I've found it difficult to find 1" threadless stems with a short reach appropriate to a 10 year-old.  I have a nice Nitto quill stem with a short reach, though.

So, I probably can't thread the fork to work with this frame with a threaded headset, and I probably can't safely use it with a threadless stem.  What to do?  Well, here's what I'm going to try:
  1. Get a threadless headset (done)
  2. Get a threaded headset (also done)
  3. Find a brake cable stop/hanger that will clamp to the steerer tube (found, but not purchased yet)
  4. Buy a bunch of 1" headset spacers (not done yet)
  5. Buy a locknut for a 1" threaded headset (done -- NOS Suntour part)
  6. Install the threadless headset, spacers and cable stop, getting the spacer stack up into the threaded zone of the steerer
  7. And finally, the theoretical part:  Instead of using a star-fangled nut, top cap & bolt, spacer stack and stem to tighten the headset, I'll use the spacer stack, hanger, and the locknut and top nut on the existing threads. 
With the open steerer top, I will be able to use the Nitto quill stem I have, as normal.

Has anyone else tried this?  It's unconventional, and I haven't seen any postings on the web where someone has bastardized a headset this way, but I don't see any reason it wouldn't work, and work safely.  Just as with a threaded headset, there will be two threaded nuts tensioning the bearings and locked against each other -- the only difference is where the spacers will fall.  And just as with a threadless headset, I'll have spacers playing a role in tensioning the bearings.  Yeah, I'm pretty sure it'll work just fine.

Guess I'll find out!  If it doesn't, I'll have to go get a new fork, I guess, and flip this one back on eBay.  I don't think I'll end up wrecking any parts in the process, and if I can't use that configuration, I'll be able to reuse one of the headsets with a new fork.  I'll snap some pics and follow-up when I find out if it works.

All for now,


No comments: