Eleven Thousand Miles

[frog]

I'm off the bike for a few weeks so I'm taking the opportunity to have a look at the Raven Tour and do a bit of maintenance.

After almost two years of commuting in all weathers I thought the drive train might need replacing.  I took a look at the bits a few weeks ago and decided a new sprocket, chain and ring would be the right thing to do.

Yesterday, I decided to do the jobs.  First the sprocket and ring.  I took that off and reversed it after 6 or 7 thousand miles.  It had very definite wear on the used face of the depressions so I knew it needed it.  The same went for the rings.  This time I had the new bits to compare with the old.  To be honest I couldn't actually see any wear in places I thought which might be vital.  To my mind I would say the depth of the depression and the wear on the faces would be the best indication of being worn out.  There was some wear on the walls where it contacts the rollers on the chain but the distance between points on the sprocket were almost the same.  In fact the only wear I could see was on the tips of the points which were rounded over very slightly comared with the new.  Equally so, there was little wear on the ring as well.  The chain had stretched.  So much I'd got no more adjustment in the EBB. 

On reflection my assessment of the need to replace the drive was wrong.  As far as I can see all I should have really done is took a link out of the chain and adjusted the EBB accordingly.  Next time I'll start to get twitchy at eighteen thousand   

I was wondering if someone could answer a couple of questions I've still got nagging in the back of my mind.  I replaced the Rohloff chain with a KMC 5120S which is 1/2" x 1/8".  I noted it is slightly wider than the Rohloff and is able to move slightly side to side on the sprocket and ring.  I asked at the bike shop for a chain for a hub geared bike and told them it was a 14 speed Rohloff hub.  Is it OK to use this chain?

When I was replacing the sprocket I layed the wheel sprocket side down on the bench to clean the muck off the hub.  When I picked up the wheel again there was about a tea spoon of oil on the bench.  At this stage the sprocket was off the hub.  Is this normal and does the sprocket form part of the oil seal on that side of the hub?

Thanks in advance for any answers

[PH]

Your observations about component life sound about right to me, it’s also worth noting that amount of wear acceptable on a straight chainline will be far greater than with a deraileur.

I was wondering if someone could answer a couple of questions I've still got nagging in the back of my mind.  I replaced the Rohloff chain with a KMC 5120S which is 1/2" x 1/8".  I noted it is slightly wider than the Rohloff and is able to move slightly side to side on the sprocket and ring.  I asked at the bike shop for a chain for a hub geared bike and told them it was a 14 speed Rohloff hub.  Is it OK to use this chain?

Your bike shop got it wrong, though it's an easy mistake to make as most non derailleur chains are 1/8", SS, track, BMX an most hubs.
It won't do any harm to run the wider chain though it might be a bit noisier.

When I was replacing the sprocket I layed the wheel sprocket side down on the bench to clean the muck off the hub.  When I picked up the wheel again there was about a tea spoon of oil on the bench.  At this stage the sprocket was off the hub.  Is this normal and does the sprocket form part of the oil seal on that side of the hub?

I noticed the same thing, though it was less than a teaspoon full, I also loose a bit through the axel. I expect it's normal, certainly nothing to worry about if it only happens with the sprocket off. As you're doing a bit of maintenance it might be a good time to change the oil, just to be sure it has enough in.

[freddered]

When my LBS removed my sprocket it dumped a lot of oil on his floor and continued to leak in my garage.  I was timing the reversal of the sprocket with an oil-change so it didn't matter but IT IS NORMAL to leak when sprocket is removed.

Initially I tampered too much with my drive-train.  Now everything is reversed I will just leave it alone and just add oil to the hub and chain as necessary.

There are no twisting forces on a single-speed/hub chain so there is no reason o replace it (for fear of breakage) for many thousands of miles.  I've never had a derailleur chain break on me (even under the considerable twinsting stress of changing gear under load) so I don't see what would cause a chain to break when it is in a perfect straight line.  You could lift a car with a bike chain I bet (but you could also break one with your bare hands if you twisted/flexed it sideways).

Summary.  Leave it alone and add oil.

[goosander]

Yes the sprocket does form part of the oil seal, if you remove it you should keep the sprocket side upwards otherwise oil leaks as you have found out.