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PostPosted: Mon Sep 30, 2013 6:31 pm 
Old School Grand Master
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Joined: Sun Aug 21, 2011 11:57 pm
Posts: 4074
Location: Antwerp, Belgium
The last few months I've been doing a lot of miles, but that seems to be taking its toll on the poor little Sbike.
Last month the original Exage BB started to feel and sound rough, so that was replaced with a NOS UN-72. As much as I prefer originality on this bike, this was one area where upgrading was really necessary to prevent future problems.
(rule of thumb : BB code's number x 100 = the number of miles it will probably last on my bikes)

However now I'm facing a combination of problems. The bike is ghost-shifting between 5th and 6th, the previously very quiet freewheel will now beat any CK or Hope hub during a decibel contest, at speed the wheels appear to be rattling over the slightest ripple in the tarmac and are constantly making dry mechanical sounds even though I'm sure there's plenty of grease in the bearings.

- I've replaced the (well-worn) jockey wheels with fancy new Tack ones, but that didn't make a difference apart from making the gear setup more finicky.
- While I was at it, I checked the mech for play and tension. No problems there.
- According to my chain checking tool the chain is okay. I also don't see anything out of the ordinary on the cassette. All tooth are nice and straight.
- I don't notice any play in the axles either and in the work stand the wheels sound and feel perfectly fine. I overhauled the bearings myself in October 2011 with Shimano's own grease. That should last a lot longer than the 5000-ish miles I've put on the bike since.

Unless I'm missing something, that basically leaves only the freewheel itself or the freewheel-cassette interface as a possible cause for all these problems.
So here's my question : can you just take any 7-speed freewheel and put it on any hub? I'd like to keep the original Exage (FH-HG50) hub, but a freewheel upgrade might be a good idea. I found an interchangeability pdf through Google, but all those part numbers are Chinese to me.
Also, how difficult it it to do this yourself? I'm familiar with regular maintenance and rebuilds, but never had to take a hub apart this far.

Normally in these cases I'd simply drop the bike off at my LBS, but lately he's been on such a roll that I wouldn't be surprised if it takes a month to repair it and the bike only goes backwards by the time he is done with it.


Last edited by Raging_Bulls on Mon Sep 30, 2013 10:28 pm, edited 1 time in total.

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PostPosted: Mon Sep 30, 2013 7:05 pm 
Old School Grand Master

Joined: Tue Oct 09, 2007 1:55 pm
Posts: 8212
Location: New Forest, UK
Sounds like the freehub body. Try to wobble the sprockets - you should find some play if it's worn out. If you lubricate your chain with GT85 or similar, it's no surprise as it penetrates the freewheel mechanism and washes the grease out.

It took me 4 dead freehub bodies to work this out over 3 years. :oops: Switched to thick lube from a bottle and I've never replaced one in 13 years since.

Anyway, if you are happy doing the hub bearings then the freehub swap is a doddle:
Dismantle it completely, removing the bearings.
Undo the body with a 10mm allen key fitted on the drive side.
Swap the body and rebuild in the reverse order.


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PostPosted: Mon Sep 30, 2013 7:17 pm 
King of the Skip Monkeys
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Joined: Wed Nov 07, 2007 4:34 pm
Posts: 26173
Location: Moomin Valley
not all freehubs mix - best look for an Exage hub to pop up on ebay - they used to as NOS quite often.

like this one:

http://www.ebay.co.uk/itm/Shimano-Exage ... 43bfbce5c8


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PostPosted: Mon Sep 30, 2013 7:46 pm 
Feature Bike
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Joined: Fri Aug 11, 2006 8:13 pm
Posts: 1143
Location: York-ish UK
Agree with Hamster: wrangling freehubs is surprisingly easy:


http://www.youtube.com/watch?v=Y0ph4zIC3-Q


It might well be shafted, but you could try spraying it out with carb cleaner (brake cleaner, dgreaser, thin solvent, etc. ) and then leave it submerged in a jar of engine oil one night; take it out and let it drip the next; and refit in the am. That gives you a couple of days to plan a new route or have a deep think about the nature of retro. And so, when you come to experience your newly quiet freehub, the overall experience will be invigorating.


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 Post subject: Re:
PostPosted: Sat Apr 26, 2014 5:42 pm 
Old School Grand Master
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Joined: Sun Aug 21, 2011 11:57 pm
Posts: 4074
Location: Antwerp, Belgium
Follow-up :


After nearly half a year of non-activity, I took the Sbike out of storage to send the wheel in for a freehub overhaul. My new LBS apparently has a trick to regrease freehubs (he says it's to do with hot grease, syringes and needles, but I suspect black magic).

Once the wheel was out the bearings felt so rough that I could barely turn the axle, yet in the bike they felt perfectly fine. :shock:
Upon closer inspection, I noticed that the cone on the drive side of the axle had somehow worked itself loose from the tightening nut and over-tensioned the bearings. How on earth did I miss that? I must have been driving over 1000 miles like that ! :facepalm:

I took the wheel to the LBS on thursday and asked him to check on the condition of the bearings and regrease the freehub.
Apparently there was no pitting in the scales and the balls themselves were still okay too. So all it needed was some new grease. If it were a modern wheel I would be on the hunt for a replacement hub right now.

£10 poorer but another lesson learnt. Just because it rolls okay on the road doesn't mean that you shouldn't take out the wheel every now and then to check the bearings.

As for the freehub, it's back to that distinctive Shimano "tick" sound. So whatever my LBS did, it worked.


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