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I am not experienced working on wheel hubs/cassettes or anything related to them. I am also not great at English, so please excuse any dumb questions I might ask.

The obvious problem is that my rear axle, and the hub(?). Has simply broken into 2 pieces. My plan is to just replace the hub and the axle, and reuse the other parts. I am however not sure if it is possible. The casualties

These parts will sadly have to go to waste. However, everything else has no problems, so I would like to take them off to reuse them.

gears

The gears are shown in the picture above. After doing some research, I believe that my bike has something called a freewheel. The notches are nearly impossible to see in the picture, but I can see the notches inside in real life.

At the moment, I do not have the tool to hook into these notches and take the freewheel off. Before I spend the money on the tool, I would just like to ask someone smarter than I, if it is even possible for me to take off the freewheel given the missing hub.

And I would also ask if it is possible to replace the broken hub? Or if am I forced to do something more extreme like buying a new wheel.

Any help or advice in what to do is greatly appreciated. If I am missing something obvious, or there is something wrong with my plan. Please say so.

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    Just buy some wheel with a cassette. Even second hand or just new. Dec 12, 2023 at 7:52
  • @VladimirFГероямслава +1. Preferably the new wheel should have a freehub design which is not prone to this kind of failure. Even better if it’s wide enough for modern cassettes (9 speed or even 10/11 speed compatible) so you can upgrade in the future.
    – Michael
    Dec 12, 2023 at 14:26

2 Answers 2

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The practical choices are replace the axle or replace the wheel. Replacing the hub would mean rebuilding the rim on a new hub, which is not cost-effective for this kind of wheel, especially since there's also the question then of whether the spokes can or should be re-used (probably no to both).

There are versions of a repair axle like you need here that are very inexpensive for an acceptable quality one, around $10US. There are two "tiers" of repair axles: inexpensive ones that are usually around the quality of what comes on most basic OEM hubs like the one you have, and much more expensive ($30-40US) premium quality ones. The former is usually going to be from one of the major OEM hub suppliers like Joytech or KT and could have other names on it as well. The latter is mostly Wheels Manufacturing. Hubs like the one in the picture are somewhat of a mixed mag between the M10x1 and 3/8"x26tpi thread sizes, so you need to measure the thread. The easiest way is that the actual measured thickness of the thread is around 9.8-9.9mm for M10 and only 9.4-9.5mm for 3/8". Then just get the one that matches the unbroken length of what you have.

Replacing the axle has these potential downsides:

  • You need a freewheel tool to do it right, plus cone wrenches. These are not expensive if you buy basic versions to do it yourself. If you have a shop do it, it's easy for the total cost to get into the realm of 50-75% of the cost of replacing the entire wheel.
  • It's common for the cones to be in poor condition by the time this happens, with at best uneven ball tracks and at worst with more extreme pitting. Before breaking, the axle is often ridden bent condition for some time, which is bad for the cones for a lot of reasons. Cones can be fiddly and expensive to replace if they do need to be. But, they may be okay, especially if in the future the bike will only be used lightly.
  • The biggest problem is that when this happens once, nothing alleviates the probabality of it happening again for the same use case (though switching to solid axle will help and make the problem more bending than breaking). Freewheel hubs bend and break axles much easier compared to cassette hubs.

Depending on budget and usage, and also the condition of the cones, it can make sense to buy the basic axle and tools for a DIY repair. What likely doesn't make sense is replacing the whole wheel with another freewheel wheel, nor having a shop do the axle swap. Both represent too much of the cost of just switching to a cassette wheel, which more or less don't have this problem.

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    One thing to add is that you need the right freewheel tool. That one looks like a fairly common type but they're not all the same
    – Chris H
    Dec 12, 2023 at 7:00
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You appear to have a 7 speed freewheel, instead of a more modern cassette.

These hubs are chronic for having an unsupported length on the right-hand side, inside the cogs.

The best solution is to find a used replacement wheel that has the same number of cogs. If you get a wheel with more cogs than the existing 7, you will need a replacement shifter and possibly a rear derailleur too. Costs do add up here.

You'll also have to match the brake type (appears to be a rim brake) and diameter/width. You can reuse the tyre/tube.

The advantage is you will have a more robust rear wheel that is much harder to bend under similar forces that broke this axle.


Your other option is to buy a replacement axle for your existing wheel. This would be best bought new. It will come with some cone nuts and perhaps some spacers.

If you want to continue with a QR then the new axle needs to be hollow, and the correct length, the same as your old broken axle.

You could choose to install a solid rear axle, which is secured by nuts, and you need a spanner to change a tube.

You will also need a new QR skewer, and a set of bearing balls for each side.

Tools: Some flat Cone Spanners, a regular spanner, and some grease for assembly should be all you require.

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    The sprocket spacing of 7, 8 and 9 speed cassettes are the same, aren’t they? You just can't use the additional sprockets with a 7 speed shifter. So theoretically OP could get a wheel with any of those sprocket numbers and it should work. Preferably with a freehub design.
    – Michael
    Dec 12, 2023 at 14:22
  • @Michael close - its 8/9/10 that are the same physical width. 6/7/8 simply got wider by adding an extra cog, but therefore 6/7/8 use the ~same width of chain. It's also possible to get a 7 speed cassette and use spacers behind it. I get mine from aliexpress cos the LBS doesn't carry them.
    – Criggie
    Dec 12, 2023 at 20:25

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