It's a 16mm nut that won't turn, and I don't want to bend my cone wrench.

The other side came off easily but was a normal nut. This side seems to have some sort of lock/ hole for a pin but I'm not entirely sure what to search for in regards to it

enter image description here http://s29.postimg.org/3v75cum3r/image.jpg

I've uploaded a picture, notice the little dip / semi circle hole on the end of the axle? I'm pretty sure this is related to whatever's stopping me from turning the nut

  • 1
    Is that nut really round, because I can't actually see a hexagonal shape there at all. If there's just narrow flat spots there someone may have used a bearing cone as a nut, in which case locking pliers are your only hope (well, they're less destructive and easier than filing proper flats onto the "nut")
    – Móż
    Dec 3, 2015 at 0:29
  • @Mσᶎ - The hex sides are there if you look closely. Dec 3, 2015 at 1:05
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    Tip for taking these kinds of pictures: holding the camera slightly off axis, and using a source of light (even a flashlight/torch) off of the camera, will show the shapes and angles better than on-axis on-camera flash. Dec 3, 2015 at 1:12
  • @junkyardsparkle you're right. Very closely! I've tweaked the image.
    – Móż
    Dec 3, 2015 at 1:46
  • 2
    @DanielRHicks impact drive only after a proper spanner/socket has failed, though.
    – Móż
    Dec 3, 2015 at 4:04

2 Answers 2


That lock groove is for a washer between the cone and the locknut, and there's no way to have a nut on the axle that locks into it. So you can ignore it.

What you need is a proper 16mm ring spanner. Even an adjustable wrench could well strip that nut. If you have to go to a bike shop or some other workshop to use one, do that. Or just buy one, since you're likely to need it.

Commonly those nuts are done up ridiculously tight for a reason. Often it's because that derailleur protector is only held on by the one nut, so if bumped it will tend to rotate and loosen the wheel nut (the one you're trying to undo). Rather than getting a proper derailleur protector (and that keys onto the frame), a "solution" is just to do that nut up really tight. Which also puts pressure on the cones, so people will often back the cones off a little to stop the wheel binding. It's a classic case of "now you have two problems" (or here).

  • A socket wrench is probably a bit easier than a ring spanner.
    – Batman
    Dec 3, 2015 at 3:53
  • I was thinking it's unlikely someone trying to use a cone spanner has a socket set already, and a ring spanner is cheaper.
    – Móż
    Dec 3, 2015 at 4:04
  • 1
    Agreed - either a ring spanner or a proper socket set with enough leverage to do the job. Possibly some penetrating oil might help, but that may not wick into the threads if its that tight.
    – Criggie
    Dec 3, 2015 at 5:40
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    Working on a Raleigh of similar age I found a spanner with a decent bit of leverage essential. Rather than pushing /pulling against the whole bike and having to hold it steady, it's sometimes easier to start with the spanner almost parallel to the chain stay and squeeze the spanner and chain stay together like a pair of pliers. Theoretically you can't apply as much force but in practice the ergonomics can be so much better that there's a net improvement.
    – Chris H
    Dec 3, 2015 at 6:54

Start with the easier solutions above, like long handles on sockets, ring spanners, and penetrating oil periodically for a couple days.

Here's your last resorts... For if the easier solutions don't work.

enter image description here * Impact driver - the least destructive. Do be super careful that you're undoing the nut, not tightening it (BTDT)

If that doesn't work, take the bike to a local workshop and ask nicely if they can use an air rattle gun.

Drift punch thing * Not a bike, but I've had to do this on my car more than once. You could use an automatic center punch, just a little off center.

If you're getting nowhere, move on to something more vandalistic.

Nut splitter * Nut splitter This will cleave the nut in twain, and hopefully not damage the axle. Nut needs replacing.

enter image description here * Heat - try heating the nut up with a butane torch. This will bugger up the temper of metals, so don't play the flame on the dropouts or anything you want to keep. Paint will likely get damaged by this. A yellow-flame lighter won't have the power, you need the tip of the lighter blue flame. Possibly combined with the auto centerpunch to shock things loose.

enter image description here * Grinder Cut a slot in the nut without touching the frame at all. If that doesn't make it loose, then use a cold chisel or a flat screwdriver or the nut splitter above to remove. And knowing dremel cutoff wheels, you may need more than one. Possibly try a 100mm or 125mm grinder, but they lack the finesse of a dremel-style tool.

How's the axle? If its toast anyway, stick the other side in a bench vice and rotate the whole bike around.

You can also use the grinder to cut through the axle and nut.

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