Rear hub replacement - advice on procedure

Rear hub replacement - advice on procedure

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anonymous-user

Original Poster:

60 months

Friday 28th September 2018
quotequote all
Here's the rear hub/wheel from my Giant Talon mountain bike. I noticed that the wheel started to feel a bit rough when rotated in free wheel mode, also noticed that when torque was applied to the hub gears through pedaling, a 'crunchy' feel could be felt through the pedals when on the power stroke. I dismantled the hub took out all of the bearings and found the cause - water ingress into the bearings on the gear side causing corrosion. Presumably water (or grit) has also got into the freewheel assembly, causing the crunchy feel when pedaling. (no I have not been using a Jetwasher!)

I've obtained a new hub assembly intending to fit it myself, might as well learn how to do it. I've been told that the innards of the hub will push out from the housing with the bearing surfaces (leaving the housing and spokes intact) then the same procedure on with the new hub then fit it to the existing housing. The side with the disc brake is perfect with no water ingress or corrosion, its the gear side with freewheel that needs pushing out/replacing. My questions are am I right in assuming that the freewheel side can be pushed or tapped out from the housing? If so how can it be pushed out? I'm told a socket has to go inside somehow and I can see what look like roller bearings when I shine a torch through the shaft hole.

Reason for the water ingress may have been too much foam chain cleaner applied around the gears when cleaning. There is a rubber cup/seal on the disc brake side, but there isn't an equivalent seal on the gear side, I think foam may have got inside and dried out the bearing. Advice on replacing the bearing appreciated - not been on the bike for 2 days and I'm suffering smile
















gazza285

10,117 posts

214 months

Friday 28th September 2018
quotequote all
A Shimano freehub? You need a 10mm Allen key IIRC, insert this into the freehub side, the 'roller bearing' is a splined hollow bolt. Undo this and the freehub will come off the hub body.

You might struggle to get the freehub unit off your new hub, as you haven't got the rim to hold onto while you undo the splined bolt.

https://www.bikeradar.com/gear/article/how-to-repl...

uncinqsix

3,239 posts

216 months

Friday 28th September 2018
quotequote all
I don't know if it is even possible to remove and replace the bearing cups in the hub. If the cup on the non-drive side is still OK, and it's just the cup on the freehub that's knackered, you should just be able to remove and replace the entire freehub body. It unscrews with a 10 or 12mm allen key. Use the cones from the new hub.

Otherwise, you can re-lace the entire new hub into the wheel.

Barchettaman

6,475 posts

138 months

Friday 28th September 2018
quotequote all
Relace the hub if it was that knackered.

anonymous-user

Original Poster:

60 months

Friday 28th September 2018
quotequote all
gazza285 said:
A Shimano freehub? You need a 10mm Allen key IIRC, insert this into the freehub side, the 'roller bearing' is a splined hollow bolt. Undo this and the freehub will come off the hub body.

You might struggle to get the freehub unit off your new hub, as you haven't got the rim to hold onto while you undo the splined bolt.

https://www.bikeradar.com/gear/article/how-to-repl...
Thank you very much, it makes sense now. I'll need to buy a big allen key to suit - Halfords?

anonymous-user

Original Poster:

60 months

Friday 28th September 2018
quotequote all
uncinqsix said:
I don't know if it is even possible to remove and replace the bearing cups in the hub. If the cup on the non-drive side is still OK, and it's just the cup on the freehub that's knackered, you should just be able to remove and replace the entire freehub body. It unscrews with a 10 or 12mm allen key. Use the cones from the new hub.

Otherwise, you can re-lace the entire new hub into the wheel.
Yes it's just the freewheel side that's knackered, other side is fine.

uncinqsix

3,239 posts

216 months

Saturday 29th September 2018
quotequote all
GSE said:
Yes it's just the freewheel side that's knackered, other side is fine.
You're lucky. Both cups on the rear hub of my commuter got horribly pitted. I ended up lacing a whole new hub in, which wasn't actually as difficult as I thought it would be.

anonymous-user

Original Poster:

60 months

Saturday 29th September 2018
quotequote all
Freewheel and bearing from the new hub assembly successfully transferred in to the existing hub casing.

The nut inside holding the freewheel needs an 11mm diameter hex drive which appears to be as rare as hens teeth. I wasted an hour or so trying to obtain a suitable drive only to find that the square drive on the end of a ratchet extension fits in perfectly .. so no need for a special tool. They were very tight to undo, and more difficult to do on the new hub as stated, but sliding the cassette back on and using a chain grip lever gave enough grip to loosen the nut.

Luckily the other side is perfect, as replacing it will require re-lacing the hub into the wheel. Presumably more expensive bikes have cartridge bearings of some sort, same as used on the bottom bracket on my bike?

I shall now take all steps to prevent water getting inside the freewheel. Will probably remove the cassette from the hub each time to clean it properly rather than doing it with the wheel on the bike. Incidentally there is an equivalent seal on the freewheel side, it's inside and not visible externally.

So now a nice and smooth drive train has been restored, happy days!



(That's the old 'crunchy' freewheel with corroded bearing attached to the rest of the new hub assy)

Edited by anonymous-user on Saturday 29th September 18:09

uncinqsix

3,239 posts

216 months

Saturday 29th September 2018
quotequote all
As it's the 11mm hex, you must have the same OE Giant brand hub as I did. The sealing on them is basically non-existent and they let water in in any sort of wet riding. I'd suggest packing the bearings with a heavy boat trailer grease, and check the fronts too.

gazza285

10,117 posts

214 months

Saturday 29th September 2018
quotequote all
I've got it now, it's a Formula hub, and what a piece of junk they are. You are right about the sealing OP, there basically isn't any, I had one on one of my 29ers, ended up changing the hub for a Shimano XT one, mainly because they were on offer from Halfords, but I haven't had any trouble since.

wobert

5,227 posts

228 months

Sunday 30th September 2018
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When I did the Formula freewheel on my GT Grade I bought one of these, perfect for the job...


yellowjack

17,213 posts

172 months

Monday 1st October 2018
quotequote all
I fear I'm too late to warn you off buying a whole hub this time, but you can get the freehub body as a separate part.

I buy mine (three so far) from PedalOn, as it's fairly local and it's where I bought the bike.

Sold under Bontrager, Cannondale, and Giant branding, among others, there are several packaged options that all fit because they're identical mechanically. They also come with an adaptor Allen socket that fits (I think) onto the end of a 6mm Allen Key to take it up to 10mm (or is it 11mm?).

https://www.pedalon.co.uk/acatalog/wheel-spares.ht...

Three random freehubs here...
https://www.pedalon.co.uk/acatalog/bontrager-appro...
https://www.pedalon.co.uk/acatalog/Cannondale-FH04...
https://www.pedalon.co.uk/acatalog/Giant-FH06-Free...
...you'll obviously need to check which one is correct for your hub but the shop can help. Different fit for cup'n'cone versus sealed bearings, and differences between freehub body length for 8/9/10 versus 11 speed, for example, but once you've got the right one you can buy several. I always buy a spare now, after one failed with little warning. They fail in different ways too. One locked up completely, effectively making it a fixed wheel bike. Another decided that the ratchet splines creating drive was over-rated and I had to cable-tie the cassette to the spokes to get home on an improvised 'fixie'.

Image attached of the Bontrager branded freehub because it clearly shows the Allen Key adaptor included in the pack...



The fault is with (sorry about this) freehubs on the lower-end wheelsets. This freehub body is poorly sealed in comparison with other solutions to the problem. Regular stripping, cleaning, and re-greasing of the cup and cone bearings can extend freehub bearing life, but they'll let you down eventually if you use the bike enough for what it was intended to do. My bike is the Giant Anthem 3, which was £1500 at full price, so not exactly cheap, but still firmly in the lower end of the Giant Anthem range...


Oh, and I did manage to salvage some life out of one of the failed freehubs when they were out of stock at the shop. I flooded the body with oil, to wash out the grit and old grease in there. It did come back to life, but with chain oil lubing the ratchet instead of grease it didn't last too long before it was grumbling again. I suppose I could rid myself of the problem if I upgraded to more expensive wheels/hubs with better weather sealing, but the replacement of the freehub is pretty simple, and not too expensive in the grand scheme of things.

wobert

5,227 posts

228 months

Monday 1st October 2018
quotequote all
yellowjack said:
I fear I'm too late to warn you off buying a whole hub this time, but you can get the freehub body as a separate part.

I buy mine (three so far) from PedalOn, as it's fairly local and it's where I bought the bike.

Sold under Bontrager, Cannondale, and Giant branding, among others, there are several packaged options that all fit because they're identical mechanically. They also come with an adaptor Allen socket that fits (I think) onto the end of a 6mm Allen Key to take it up to 10mm (or is it 11mm?).

https://www.pedalon.co.uk/acatalog/wheel-spares.ht...

Three random freehubs here...
https://www.pedalon.co.uk/acatalog/bontrager-appro...
https://www.pedalon.co.uk/acatalog/Cannondale-FH04...
https://www.pedalon.co.uk/acatalog/Giant-FH06-Free...
...you'll obviously need to check which one is correct for your hub but the shop can help. Different fit for cup'n'cone versus sealed bearings, and differences between freehub body length for 8/9/10 versus 11 speed, for example, but once you've got the right one you can buy several. I always buy a spare now, after one failed with little warning. They fail in different ways too. One locked up completely, effectively making it a fixed wheel bike. Another decided that the ratchet splines creating drive was over-rated and I had to cable-tie the cassette to the spokes to get home on an improvised 'fixie'.

Image attached of the Bontrager branded freehub because it clearly shows the Allen Key adaptor included in the pack...



The fault is with (sorry about this) freehubs on the lower-end wheelsets. This freehub body is poorly sealed in comparison with other solutions to the problem. Regular stripping, cleaning, and re-greasing of the cup and cone bearings can extend freehub bearing life, but they'll let you down eventually if you use the bike enough for what it was intended to do. My bike is the Giant Anthem 3, which was £1500 at full price, so not exactly cheap, but still firmly in the lower end of the Giant Anthem range...


Oh, and I did manage to salvage some life out of one of the failed freehubs when they were out of stock at the shop. I flooded the body with oil, to wash out the grit and old grease in there. It did come back to life, but with chain oil lubing the ratchet instead of grease it didn't last too long before it was grumbling again. I suppose I could rid myself of the problem if I upgraded to more expensive wheels/hubs with better weather sealing, but the replacement of the freehub is pretty simple, and not too expensive in the grand scheme of things.
That’s the same freewheel I bought.

Unfortunately the hex drive they supply wouldn’t fit down the access hole when fitted to my 1/4” extension.

The tool I linked to above fitted a treat as if it was made for the job

Plus being 3/8” drive was more suited to the installation torque.