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I have an old bike I need to repair (including flat tyres!) Unfortunately it has rounded nuts on it and can't seem to unscrew them.

Is there an easy non expensive way to remove them without damaging them?

  • 3
    That image shows someone using the wrong sized spanner - it is far too big. – Criggie Feb 22 '17 at 9:37
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    yes, I know what stock images are. They're also utterly useless for showing us what your bike looks like. Consider removing the stock photo and adding a clear and well-lit photo of your bike's problem area. – Criggie Feb 22 '17 at 10:14
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    Use a pipe wrench. Then discard the nut and find a new one. – Daniel R Hicks Feb 22 '17 at 12:53
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    @user2326637 what's the point of linking to a stock photo if it's not representative of your issue? – Jules Feb 22 '17 at 14:07
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    @user2326637 The image adds literally nothing. However, it has at least two disadvantages: it takes up space on the screen and everybody who wants to see the answers has to scroll past it; you've not given any attribution so we don't even know if it's legal to display that image on stackexchange.com. – David Richerby Feb 22 '17 at 16:04
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If the nuts are rounded they're stuffed. You want to remove the nuts but not damage other things, like axles.

I'll assume you're talking about axle nuts, but the same ideas apply to all nuts, bolts, and even screws to some extent.

So your nuts look something like this:

enter image description here

  1. Clean the flats up with a file. Use a medium flat file and smooth off the lumps of deformed metal in the corners. Keep the file parallel to the flats and take your time.
  2. Get the right-sized tool. An axle nut is often 14mm, but that's not quite 9/16" of an inch. So try the near-size tools. They should go on snugly and have minimal play
  3. Use a 6 or 12 point socket, or a ring spanner. There's even specialist axle nut spanners as pictured which work quite well. enter image description here .Do NOT use an adjustable crescent!
  4. Leverage - get a length of pipe and slip it over your socket driver handle. 50cm to 1metre should be ample leverage. Any more than that and you risk damaging the tool.
  5. If that's not helping then stop here, and get some penetrant oil like PB Rust Blaster, or CRC or anything that will soak in and help break up corrosion. It could be the nuts have rounded off because they're simply on really well. Also look for pins or any other secondary retainers. My landy uses tab washers, which are designed to be folded over nuts to hold them from vibrating loose.

So all the easy fixes have failed. You're going to have to get brutal and your nuts probably won't survive the later options.

  1. Vise Grips or a Pair of Stiltsons, aka a pipe wrench. enter image description here enter image description here Leverage is your friend, but watch the slip-zone should something give way.
  2. Cold chisel works well on larger diameter things, but small nuts not so much. I'd not bother with this. The shock of hammering may upset your bearing cones and cups inside the hub and even the headset takes abuse.
  3. If you have one, try cracking the nut in two with a nut splitter enter image description here
  4. Finally you can get a small 3" or 4" grinder with a cut-off wheel and thin down the nut. The danger here is slipping and damaging the axle, or the wheel hub, or yourself. Plus there's hot spitty sparks which can set fire to lubes and oils and cloths and anything. A dremel tool with a 1" cutoff wheel might work, but the wheels tend to shatter quickly which is also expensive.
  5. If you can't cut the nut off, then consider cutting the whole axle off. The nuts pictured above would work well because the flange is a good guide of where to cut. Once the top part of the nut is off, the flange may slide right off at best, or its only got a couple of threads to undo and you have more leverage. A new axle is absolutely needed because it will be too short, and will have overheated changing its hardness.

Sometimes heat can help, but its also able to cause worse damage. A steel fork should be fine, but its very easy to overheat aluminium. Carbon fibre will melt badly or worse it might overheat, loose strength, but look undamaged. This is the worst case, so only apply heat if your fork is steel, and there are no plastic parts in the area.

You can also use cold, sometimes, to "shrink" metals and break things loose. I've found that carefully-applied heat to be much more useful.

Once you get the wheel nuts off, consider replacing the axle and nuts anyway. A new axle with wheel nuts, two cones, and lock nuts shouldn't be too expensive.

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    For a damaged nut I'd even avoid an open-ended spanner (fixed crescent); I'd also put the penetrating oil earlier in the sequence. This is just a matter of opinion though. Definitely discard the nuts after this though – Chris H Feb 22 '17 at 10:27
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    One word of warning: Maybe the OP is talking about secure nuts like Pitlock? Those are round on purpose and probably made out of some high quality steel. Though you could probably still grind two flat, parallel sides into them and use a pipe wrench or wrench. – Michael Feb 22 '17 at 18:27
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    @Michael, good point, and another reason for the OP to post real photos – Chris H Feb 22 '17 at 19:05
  • @Michael thats a good thought, but pitlocks don't have flats to round off. If OP had posted a photo straight off then we'd know. – Criggie Feb 22 '17 at 19:43
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  1. Spray generously with penetrating oil (something like WD40)
  2. Give said oil time to work its way into the seized thread (15 to 30 minutes)
  3. Use a vice-grips to grasp the rounded nut and unscrew
  4. If unsuccessful, go back to step 1
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    5. Get new nuts. – RoboKaren Feb 22 '17 at 16:53

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