resurfacing/grinding a new bearing surface in a freehub

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cyclop
Posts: 251
Joined: 3 Oct 2013, 7:49am

resurfacing/grinding a new bearing surface in a freehub

Postby cyclop » 14 Aug 2019, 10:29am

Possible or not?Usual issue,irreplaceable drive side bearing in the freehub,can it be reground?

Brucey
Posts: 34709
Joined: 4 Jan 2012, 6:25pm

Re: resurfacing/grinding a new bearing surface in a freehub

Postby Brucey » 14 Aug 2019, 10:58am

which hub do you have? I am assuming it is a shimano -type one, in which the freehub body also contains the RH main hub bearing.

If the freewheel bearing (that only turns when freewheeling) then 'yes' .

However if you mean the main hub bearing (which turns and sees load whenever the wheel turns) then 'probably not'.

In a shimano-pattern freehub (in which the freewheel turns on separate bearings on the moving part of the hub) then renewing the freehub body also renews the RH main bearing cup.

[For clarity, in the alternative pattern, the freewheel body turns on ( cartridge type) bearings which are mounted to the fixed part of the axle.]

The freewheel bearings see either load or movement, and the parts are practically 'all hard' so will take a light grind. However the main bearing cup sees much higher loads (practically one ball at a time) nearly all the time. Grinding the cup is liable to leave a bearing part that won't be as strong, one way or another.

FWIW its worth asking yourself how any damage might have occurred; if it is to do with bad setup of the hub, it'll happen again. FWIW QR cup and cone hub bearings should be set with a little free play that just disappears as the QR is tightened fully. If there is no free play when the wheel is out of the frame there is too much preload and the bearings will be much more likely to be damaged.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

cyclop
Posts: 251
Joined: 3 Oct 2013, 7:49am

Re: resurfacing/grinding a new bearing surface in a freehub

Postby cyclop » 14 Aug 2019, 4:12pm

Thanks for that info.I,ve just rescued some old wheels from my pals bin for bits and pieces.Front hub,v.good,rear hub,not great,freehub probably alright for the mtb,rim tapes,spokes to keep cats off the garden.ShimanoR500.