I have a 2009 Specialized Hardrock, with a Shimano FH-RM30 QR rear hub and a Shimano MF-TZ31 freewheel. I took apart basically the whole wheel assembly trying to repair the freewheel. Now it's a week later and I need to resassemble, but I don't recall how the axle was configured. I think I have the pieces in the right order in this photo(?), but in the middle row you can see a washer and a spacer...no idea where those would go, and my Google searches are coming up empty. I'm sure a real mechanic would know how, where and why to use those spacers, but I'm clueless. Can anyone help?

rear axel parts

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    When undertaking a complicated disassembly it is always helpful to take step by step pictures of the process.
    – Carel
    Apr 24, 2021 at 17:51

2 Answers 2


This isn't FH-RM30. It's a freewheel hub. MF-TZ31 is a freewheel and the drive side axle hardware pictured is that of a freewheel hub. Also the skewer and dust shield type (thick and inflexible) are non-Shimano.

As you indicate in the comments, the dust shield can't go over the thin spacer. So therefore the thin spacer needs to be next to the cone. The shield should be able to fit over the locknut by itself.

Always make sure the drive-side cone and locknut are torqued hard against each other before beginning reassembly.

  • Thank you. What baffles me is that the thin spacer and locknut can't fit through the end of the dust cap. So it looks like you have to put the dust cap on first -- which then prevents you from holding or tightening the cone nut?
    – supernaut
    Apr 25, 2021 at 18:07
  • @supernaut You pinch the dust shield and flex it over everything. Apr 25, 2021 at 19:02
  • It's a hard shell -- no flex...
    – supernaut
    Apr 26, 2021 at 20:24
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    @supernaut Previously I saw the external cam QR and figured the Shimano one got replaced at some point. Now I see that what's going is that this isn't FH-RM30. You have a freewheel and all the FH- hubs are cassette hubs. I should have noticed before that the drive side hardware has a freewheel hub type spacer, that's my bad. The inflexible dust shield you have just jams on. If the thin spacer makes it impossible to get on, reverse from how I said. Apr 26, 2021 at 21:13

Shimano provides all sorts of technical documents; "Exploded View" or EV documents show how all the components of a part go together and gives part numbers and names and some key dimensions. That's what you want in a situation like yours.

si.shimano.com is the technical info repository for Shimano.

Searching google for "Shimano FH-RM30 QR rear hub EV" produced the link https://si.shimano.com/pdfs/ev/EV-FH-RM30-8S-2388B.pdf among others, which is the EV for the 8-speed version; among the other links was one to an EV for the 7-speed version.

  • Thank you. This is a 7-speed freewheel. I'll take a look.
    – supernaut
    Apr 25, 2021 at 18:08

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