I have a very old bike (circa 1996) with broken Shimano Altus 7 speed, hyperglide-c freehub. The freehub is freely rotating in both directions.

I had removed the cassette, but it seems that there is no way the freehub could be removed with allen wrench: there is nothing on the drive side and it seems like torx slots on the other.

Does it make sense to rebuild the free hub without removing from the wheel? Does it make sense to take metal saw to cut part of the thing first and then unscrew the rest?

Update: I am considering this tool to disassemble and fix the freehub without removing it from the wheel.

Another update:

The view from the drive side enter image description here The view from the other side, the hole diameter is 12mm, it seems like there are some slots there but I am now sure whether I need 10 mm wrench or something else. enter image description here

  • 2
    Adding a photo to your question might help - clear and clean and well lit ideally.
    – Criggie
    Dec 23, 2020 at 23:13
  • Perfect! That photo shows exactly the tool you need.
    – Criggie
    Jan 1, 2021 at 3:02
  • @Criggie. Sorry I did not get what is this tool? Is it 10mm Allen wrench?
    – zzz777
    Jan 1, 2021 at 15:14
  • 1
    yes - exactly right. Its longer than a little "bit" you might put into a screwdriver handle, you need the leverage. Clamping the tool in a bench vise can help too... you need a lot of torque, which can be generated by turning the rim of the wheel with your hands. If you need a photo I can go set one up showing this.
    – Criggie
    Jan 1, 2021 at 23:38
  • @Criggie. 10 mm allen wrench fit into the slots but after applying some force it started to simply slip. Thanks for help. It seems that sawing it off is the only option that remains.
    – zzz777
    Jan 5, 2021 at 15:17

2 Answers 2


Cutting might work, but there could be follow-on problems so its very last-resort. If you go this way, cut parallel to the cogs, between the middle two. So a 10 speed you'd cut between 5 and 6. This should remove any lip on the bolt, allowing the remains of the body to slide off. You'll then need to use grips to undo the half-bolt poking out.

First I'd suggest you start with conventional removal.

Initially shove a 10mm hex driver in the hole where the axle goes. A short one might not engage, you may need a longer one. I've also seen bikes with 8mm or 12mm hex fittings down inside the hub, so try different sizes till you feel a positive engagement.

You also require a lot of torque to break a freehub bolt loose. I have a 12mm hex driver that is 650mm long and copes well. If you use a hand-sized hex driver then it may need some taps from a hammer, mind out for breakage risk ! You can also secure the hex tool in a vise pointing up, and use your hands on the rim for torque/rotation.

Every freehub bolt I've undone was normal right-hand thread.

Update - your photo clearly shows a 12 pointed socket in the middle of the freehub. This will fit a 6 sided hex driver, most likely 10mm but it might be 11mm or remote chance of being some weird imperial fractional size like 25/64".

Buy or borrow a 10mm hed driver tool something like this :


To show the end you need:

enter image description here

Not a silly little bit for a screwdriver handle. Then use the entire rim as a grip and unthread the bolt that is in the middle of your freehub.

You can do this, without cutting - and remember if it goes badly, the freehub was dead anyway.

  • I removed cassette, I have just have a bare freehub attached to the wheel to deal with. How bad is the idea of disassembling freehub without removing it from the wheel?
    – zzz777
    Dec 24, 2020 at 15:49
  • 1
    @zzz777 the more you can remove, the less you have to cut through with a hacksaw! Downside, disassembling often means removing some kind of retainer from the back side, which is currently pressed against your wheel.
    – Criggie
    Dec 24, 2020 at 21:28

I do not believe there are any from that era that don't take a 10mm wrench through the drive side.

The simple thing to do is remvoe the freehub with the 10, gently pry up the rubber seal on the back, note its direction, and shoot air/solvent/lube/oil/etc through it depending on what you've got and how bad it is, then finish with a heavier oil like Phil.

Edit: It indeed takes a 10mm allen.

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