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recently my rear wheel started wobbling so I wanted to check its rear hub, bearing and axle.

I have a Shimano HB-RS470 hub which is a thru axle hub, and it look exactlly like the one in the picture below. The axle was very loose and I could move it from drive-side to brake-side by about 5mm, so I decided to clean and retighten it.

The problem I ecountered is that the axle and its nut (marked with number 2 in the picture) is not acting like a single piece, as I think they should. More precisely, if I firmly tighten no. 5 nuts, then I can spin the no. 2 nut while the axle itself remain unspinning. It makes the axle impossible (for me) to tighten even if I use 3 wrenches - 1 for tighening the nut (the inner one near brake rotor) and 2 for holding other nuts.

It also might be worth mentioning that if I tight no. 5 nuts tightly I'm unable to insert a thru axle (the most inner axle, not the one shown in pic) into the no. 2 axle from picture. To fit it I need to loosen nuts a bit. It wasn't like that before so there might be something wrong.

Is it expected to behave like that, or should the axle with its nut be a single solid piece? Visually it doesn't look broken, there are no cracks. And to spin nut and axle separately I need to hold the axle really tight.

Do yout think it's broken or there is something I'm missing out?

Thanks in advance, cheers

shimano-tiagra-fh-rs470

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    Do you have a cone spanner? A really thin spanner to go on the right-most #5 (as in not the end nut which can be operated with a normal spanner)
    – Criggie ♦
    Commented Apr 20, 2023 at 10:47
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    As Criggie pointed out the Shimano hubs are cup and cone (whereas most modern hubs would be sealed cartridge bearings, Shimano is sticking with "if it ain't broke"). Aside from using the correct tool are all the bearings in place? Cup and cone require tension on the bearings. I don't know if the axle nut should spin under torque but it could be a case it's bottoming out (no bearings, bearing surfaces worn too far). With it moving as much as you indicated I'd be worried about damage or missing bearings. That style hub requires periodic adjustment.
    – shox
    Commented Apr 20, 2023 at 15:27
  • Bearing in the hub were in fact messed up and it made whole wheel wobbly but it was not a problem for me to solve it. It came out that the axle and its nut were put together using some kind of a glue and it just gave up when I tightened the axle too strong. All the other parts were in good condition.
    – Wojtek W
    Commented Apr 22, 2023 at 14:18

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The drive side cone is intended to be immobile on the axle with these designs. If you asked Shimano, the fix here would be replace the axle (probably involves buying the "Complete Hub Axle" part).

I believe the way that some of these work is the cone is held on with either epoxy, very high-strength threadlocker, or retaining compound. If all that's going on here is just a failed bond, there's likely nothing stopping you from re-bonding it. For example, if it's a threaded connection, it should be fine to take the axle all the way out, thoroughly clean the broken interface, coat the threads with epoxy, screw the cone on, wipe away excess, then leave it aside for 24 hours before putting the hub back together.

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  • You are quite right - it came out that axle and its nut should act as a signle piece. However, the nut is not permanently attached to the axle, they are just really hard pressed together along with some glue/expoxy. I must have tightened it too strong so the epoxy gave up. Other than that the axle is all good. Thanks for help!
    – Wojtek W
    Commented Apr 22, 2023 at 14:13

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