Rohloff's load-bearing bearings

[expr]

Hi,

The changing of the bearings can be done by yourself with the right tools and knowledge / advice.

The first thing to do is to remove the sprocket from the driver body with a good strong chain whip, and the removal tool from thorn/ rohloff.

Once the sprocket has been removed you can tip out the oil into a container through the bearing itself  for re-use later if required. Then remove the torx screws from the hub cap, carfully remove the gear hub from the casing and place on a very clean cloth out of the way.

You may find that the small nylon (white) joints have also come out loose, don't worry keep to one side for later you should have 9..

Also be carefull with the paper gasket this is delicate, but can be reused if OK. Then with a Small plastic trim tool the oil lip seal can be removed but its advisable to use the rohloff lip seal tool to do this, the only difference there would be it has to be taken off with the hub still complete, as long as you can be carefull putting the lip seal in after its OK without the tool.

Once the oil seal is out of the way pay attention to the dimensional measurement in depth that the

 http://simplybearings.co.uk/shop/product_info.php?products_id=5170
 
bearing has been inserted to as this is a (floating) bearing but must be put back in the (ball park) area for good fit. It still has an interference fit for integrity, but there is no backstop to push the bearing up to..

After taking note of the depth, I can think of many several ways to remove the bearing with out using a conventional / bespoke manufacturer specific tool, but with carefull intuition this can be achieved with a little imagination. Using the (Tapping out) method is always a last resort on my list , only due to the fact that this can cause marring of the soft aluminium casing and because this is a (floating) bearing it is essential that its mating surface is kept perfect.

I used some 16mm threaded rod with various sockets and end caps to remove my bearings and this acts as a pusher and a puller also so is great for installation.

Put a socket in the hub with a large flat washer (backstop) on it then a nut with the threaded rod coming out of the driver side long enough to go through a larger socket 50mm id or larger for the bearing to pull in to, then fit a (backstop) washer and another nut, then simply tighten the nut slowly to release the bearing into the socket and remove.

When fitting the new bearing, do not fit any retaining compound on the bearing just a little oil, you may now have to tap the bearing around the periphery to get it started, this MUST be square going in before using the puller/ pusher to reinsert the bearing. Turn the puller around so that the bigger socket is inside the hub this time and a socket of 46mm od approx is now on the outside which will pull the bearing back in taking note of the depth required for installation.

Once the bearing is back in and at its correct dimension the oil must be cleaned with solvent around where the lip seal will go, if you are pushing this in manually this can be done now, if using the rohloff tool this will have to be done when the hub is back in the casing, if doing now then using loctite seal put a smear around the OUTER of the lip seal and around the id of the hub case and carefully press in with a flat face until flush with the case and leave to dry for an hour.

After an hour wipe the inside of the lip seal with oil and proceed to fit the hub back in to place, this will require you to put a little grease on to the nylon joints to stop them from falling while inserting in to the hub, also taking care not to damage the paper gasket.

Then fit the torx screws using loctite blue 243 and being carefull not to over tighten, the oil can now be fed back through the open bearing face on the driver side, once in screw the sprocket back on, because you have taken the hub apart and because the driver bearing is floating this can cause misalignment of these to components which is rectified by whacking the non drive side as close to the hub center a few times to re align the two parts, DON'T WORRY this is normal procedure for this hub and no damage will be caused although the use of a soft faced rubber shock hammer is much preferred or a small piece of wood with a normal hammer to absorb the shock or prevent hammer rash etc..

This is to bring the axial line of the driver in to the axial line of the floating bearing, and the symptoms of a poor alignment are very poor freewheeling with the bike turned over..


The only other part that could cause the freeplay on the driver side is the driver bearings which sit inside the driver which in turn sit inside the main 47mm outer hub bearing, double check that the freeplay is in the outer bearing first.

Once this is complete tighten the sprocket fully and test the hub.

Regards

Dave.

http://www.photobox.co.uk/album/168875892

[jimmer]

Welcome back. This is the kind of knowledgable, contribution that we could have missed out on.

[expr]

Thank you Jimmer, PM sent.

[MilitantGraham]

Thanks, expr, that's very helpful.
I'm a bus mechanic, so I've got access to big sockets and experience at making improvised pullers.
It's definitely the single, larger bearing that's faulty. There is clearly movement between the hub body and the sprocket, while the sprocket appears secure in relation to the axle.

Do you happen to know the dimensions of the seal and if it's available ?
I guess it must be 47mm OD to match the bearing and I could measure a sprocket to get the ID.

[expr]

Yes that's correct, the od is 47mm the id is the same as the od of the sprocket, plus the thickness of the lip, I'm not a 100% but do seem to recall its got a wound spring tensioner also as standard lip seals do, to keep tension on the axial load, its a single lip too. it would be advisable to get one from Thorn they have them in stock and  the seal puller and inserter although its quite expensive for a one off, also note that rubber of the oil seal is on the rohloff specific has been made to suit the oil.

The one size specific socket or alike is 45/ 46mm this is requires to pass through the body when pulling in either direction, the larger socket that you pull in to you can wrap soft tape around the edge to prevent marring on the body  etc...

[brummie]

Rohloff and Thorn have done a fine job of brainwashing people into thinking these hubs are indestructable. Bearings are largely er, bearings and even in oil bath sooner or later they'll need replacing.

I was under the impression that no hub had failed in terms of the gears & providing drive?
My hub was performing flawlessly despite ( IMO ) 'the excessive play in the bearings' prior to returning it to Germany for 'tinkering' & bearing replacement.

[expr]

Yes there seems to be a bit of misnomer surrounding the failure of hubs, there are several cases that I can recall that have ruined the hub bearings beyond use. This tends to be swept under the carpet most of the time.

I remember one case where straw had become lodged in the oil main oil seal which although not much oil was lost, there was water ingress which resulted in rather a poorly set of main hub bearings..

So I guess in that case you can't really blame rohloff, but non the less this has caused problems for the rider.

I've known a few cases similar too, but what rohloff are suggesting is that there has not been a case where a rider has not been able to carry on with their tour due to mechanical failure, so you take from that what you will.

What I can say though, is that the wheel / hub did have to go back to Rohloff for repair. Whilst on tour...