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This evening in trying to true a rear wheel run over by a car I managed to snap a spoke on a 24-inch rim.

I have some salvaged spokes and spoke nipples from a destroyed 26-inch mountain bike rim, and I've eyeballed one of the 26-inch spokes and cut it with lineman's pliers to about the length of the 24-inch ones, but now I'm trying to figure out how to hammer or otherwise squash the spoke end that connects to the hub into a hemispherical shape to be retained by the hub.

Is there a method to do this that's reasonably simple, or would I be better off just buying some replacement spokes specifically for the 24-inch wheel?

Thus far I've tried using a workbench vise to hold the improvised spoke in place, applied heat with a butane torch for around a minute, then tried to hammer the tip to try to blunt it, but to no effect. The vise couldn't keep a good enough hold by itself to enable me to basically squash the head into that dome-like shape.

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  • This sounds like you cut off the "lower end" with the bent knee - I would have cut off a bit of the upper part with the screw windings and reapplied the winding (usually left-wound) to fit the head again.. done
    – eagle275
    Feb 7 at 9:10

4 Answers 4

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Answer: Buy new spokes.

A spoke is threaded not with a die, but with rollers. The difference is that a die cuts away metal leaving a thread with an OD no-larger than the original. A roller will cold-form the metal, physically pushing material from the valleys to the peaks of the thread.

Here's a thread roller in use. They're significantly expensive, so beyond the home-workshop. The blanks are probably about as expensive as a fully made spoke, but a shop would not have to stock every possible length and thickness and head combination which is a saving.

From video linked below

The only way it might work is if you used a fatter spoke and a die, but then it would look thick and have different mechanical properties to the thinner spokes nearby.

On the other end, trying to hammer-form the J bend is asking for problems. Anything you can make with a hammer can be unmade by the pressures of riding. Even truing the wheel will be hard because the nipple will exert tension and your cold-formed J bend will relax.

Given one spoke has snapped, there's an excellent chance more spokes will go too. Buy some spares and shout yourself some new brass nipples too.

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  • My LBS was unable to supply exactly the weird spokes I wanted (15 gauge and 185mm) so I used this source to custom-make, and they were perfect while a dozen cost less than one spoke at the LBS. Downside, it took weeks to arrive. jqorg24.aliexpress.com/store/809083 There are plenty of options.
    – Criggie ♦
    Feb 5 at 3:44
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    I'd like to accept all answers received and have upvoted them but picked yours for the benefit of videos into the thread roller which is way beyond my hobby cyclist price point. Have ordered some new spokes and nipples, thank you!
    – Darth Continent
    Feb 5 at 20:31
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    @DarthContinent thanks - good luck with your repairs. If you do this kind of thing a lot, save reusable spokes and store them in separate bunches/bags by length. I have a stack of old 20mm plumbing PVC pipe with endcaps, and each has a different length of spoke inside. Long term I was going to put them in a hanger made from webbing strap, but for now all the pipes are in a box.
    – Criggie ♦
    Feb 6 at 1:36
  • I can't UV this answer because the OP's question indicated that OP was keeping the thread end and trying to figure out how to replace the hub end.
    – shoover
    Feb 6 at 19:48
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Buy a new one, they cost cents, so the only issue is does it take longer to drive to a bike shop than rehash an old spoke. Used spokes are prone to failure, anyway, heating the spoke enough to create the end dome will affect the hardness to the point I believe the chances of a long-term successful fix, doing it your way, are at best slim.

If for some reason you must reuse a spoke that is too long, best way would be to use a die and cut a thread to the correct length at the nipple end (Edit: see @Criggie's subsequent answer on why this won't work). I would leave the die below the cut point, cut the spoke then remove the die, reforming and thread distortion caused by cutting (Nipples being aluminum or brass will be destroyed by a damaged thread).

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    This is undoubtedly the only way to shorten a spoke and leave it mechanically sound, but if the spoke is double-butted then it may be too narrow at the new end to mechanically engage with the nipple. (Of course if the spoke is single- or double-butted you have the same problem at the other end, with even worse results.)
    – DavidW
    Feb 5 at 3:59
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    You're lucky if you've got a bike shop that stocks a decent range of spokes (or indeed any spokes). A few shops round here have common lengths for common wheel sizes, but they'd have to order anything unusual - like for a 24" wheel. I have to get mine mail order from a wheel builder/spoke supplier (who happens to be in my city, I think I could order and collect).
    – Chris H
    Feb 5 at 9:52
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    Just to confuse matters, the word "die" is sometimes used in the context of thread rollers, by people who should know what they're talking about. The thread is unusual, and a cutting die, even if it worked, would be hard if not impossible to find.
    – Chris H
    Feb 5 at 9:54
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The head of a spoke is carefully made with a specific shape. Your homebrew version might not sit correctly in the hub's spoke holes (making the tensioning process more "interesting"), and irregularities might even accelerate stress fractures at the hub holes. There's also quite a bit of materials science going into the heat treatment of the steel, which you are unlikely to be able to replicate with a blowtorch. Buying a new spoke for a dollar or two is by far the safest, cheapest, and easiest option.

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There's no way you'd form a spoke head with hand tools. You couldn't grip it tight enough in a vice.

I can't see me ever being in this position - my bikes generally have enough spokes that I'd rather run with one missing (especially as I have disc brakes), and on the tourer I carry spares.

But if you really had to do this to get you back to safety (like a rim brake wheel that wouldn't otherwise true enough for the brakes to be usable), and you had an over-long spoke, and you had 2 pairs of pretty sturdy pliers, I'd bend the spoke like this:

Least worst way to fake a spoke head

I'd expect truing to be difficult, and to need repeating 2 or 3 times before it settles down. Note that the bend highlighted in red would need to be finished off after lacing. This combined with the makeshift J bend is likely to damage the flange making future truing with a real spoke harder - at least.

Of course the chances of having the tools in the middle of nowhere are slim, and if you're near a workshop you can probably do better.

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  • This is definitely the right answer and is how spoke repair and/or wheel building has been done in many times and places. The spoke just has to be worked into a U shape. It works fine.
    – Nathan Knutson
    Feb 6 at 20:34
  • I wonder if there's any chance of achieving this with just one pair of pliers and the hub flange itself? I'm afraid I can't picture how exactly to do it - I guess it would be very fiddly feeding the spoke in, and then keeping the bend sharp while the rest of the spoke remains straight. But if you insert it just the right amount, I would like to think the flange will provide enough leverage/support to bend the spoke, wouldn't it?
    – pateksan
    Feb 6 at 23:46
  • @pateksan I also think that you could get your bends done that way. The biggest challenge would be getting them situated at the right spot so that you can get the spoke to final tension without running out of threaded length. I'd expect there to be some settling-in that needs to be accounted for.
    – Nathan Knutson
    Feb 7 at 5:44
  • @pateksan quite possibly. Or pliers (the ones I carry are probably too small) plus another portable tool. I wonder if you could use a chain breaker to support the spoke. In the absence of measuring tools, you'd need to use a good spoke to gauge the length
    – Chris H
    Feb 7 at 6:40
  • I might have a play at some point, using roadside tools. I have old spokes (and old hubs) to spare
    – Chris H
    Feb 7 at 9:35

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