So, my original plan has kind’ve failed. The threadless headset I bought is just too tall, meaning one of the locknuts won’t fit. Further investigation indicates that people usually saw off part of the head tube to make this kind of alteration work. That’s not something I’m prepared to do!
I’m almost glad, however, as the alternative is to replace the entire fork and put on a new threaded headset and a proper quill stem. It’ll look way better than the original fork, and apparently it’ll improve handling a bit. Also, I won’t have to file down the dropouts in order to get the front wheel to fit. Unfortunately, the only source I’ve found for a replacement fork has currently sold out, so I’ve been investigating alternatives. There’s lots, so why not share what I’ve found?
Option 1: Replace the headset only.
This was my original plan, as it’s cheap! Merely buy a 1″ threadless headset that has the lowest profile top race that you can find. The original nylon headset (if you can call it that) is only about 6mm tall, so I’m not sure if it’s actually possible to buy a headset that small. If it’s much larger, then you might have to live without one of your locknuts, or you might have to shorten the head tube by cutting part of it off.
I had an extra thought about the dangers of removing a locknut.. are two locknuts really necessary on a Raleigh Twenty? The fork/headset configuration bears more resemblance to a threadless setup than a threaded setup, in that the QR adjuster clamps onto the fork in the same way as a threadless stem clamps onto a fork. The difference is that there’s nowhere to put a star nut thingy on an R20, so there are locknuts instead. Also, I found this on Sheldon Brown’s website, where he uses a seat clamp to hold a fork in place. It’s probably not good enough for most bikes, but for a bike that’s only going to be used now and again, for short distances, going very slowly, and on fairly flat surfaces, then it seems like quite a viable solution! I think I’d upgrade the R20 QR to a seat clamp, however.
edit: I suppose the QR could be omitted, rather than a locknut, which would mean buying a new stem. You have to be careful using quill stems in the original fork, because if the stem wedge applies pressure to the slotted area, it can split the fork!
Pros: Cheap! Get to keep adjustability of handlebars.
Cons: Might need to shorten the head tube, otherwise locknut dubiousness. Have to use the original fork.
Option 2: Replace the fork, headset, and stem.
It is possible to buy forks that have steerer tubes that’re even longer than the original R20 fork, in rigid or suspension styles. Something to do with recumbents using them. Unless it’s an actual R20 fork, the thread on the forks are standard, so any threaded 1″ headset will fit. A new fork will mean that the stem will also need replacing, as the fork won’t have a slot cut out of it to allow the stem to be gripped by the quick release. The steerer tube might need cutting if it’s too long (not as scary as cutting the frame itself).
Pros: New, better made fork, with modern dropout spacing. You might even find one with brazed-on brake fittings or suspension!
Cons: Potentially quite expensive (estimate for my plan is £40). Will probably need to cut the steerer. Un-adjustable stem height.
Option 3: Use a short fork with a steerer extender, new headset, and new stem.
As forks with long steerers are a bit pricey, you could use a normal fork with a steerer extender, if you can find one. Most extenders that are on sale are threadless extenders, which makes things a little weird, but there are 1″ quill extenders, that basically bolt on a bit more tube on top of the steerer using a quill wedge. The ones on ebay are called handlebar risers, and add 100mm, which is enough to make a standard BMX fork usable. They’re not threaded, though, so I’m not sure how useful they’ll actually be.
Pros: Can use any 20″ fork you want
Cons: Same as option 2, plus I’m not sure how useful a riser is.
After thinking about the locknuts, I think I’ll go back to the original plan. I’m still really tempted to replace the fork completely (mainly because BMX forks are so much cooler!), but it’s £40 that I don’t really have at the moment.. £23 for the fork, at least £8 for the stem, £10-ish for a headset. Compare that to the £4 I spent on the headset, and £10 tops for a BMX seat clamp.
ooh, and I really need to get around to measuring the head tube length and steerer length! 😛
UPDATE: Steerer and head tube measured! 235mm and 186mm, respectively. I couldn’t find my proper steel rule, so I had to use a giant wobbly one, so give or take a mm or two. I’ll add them to the measurements on the previous post.