Technical > Transmission

How do my teeth look?

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martinf:

--- Quote from: steve216c on July 19, 2021, 12:26:42 PM --- I'll replace with brand new Truvative 42 steel chain ring, a new Connex 808 (purchased as on hand spare when I mounted the current one 11,000 km ago) and a new splined carrier with new sprocket to replace the old style sprocket still in use.

--- End quote ---

Be careful when ordering the splined carrier.

There are two different models. The thinner one gives the chainline closest to the screw-on sprocket:

https://www.rohloff.de/en/service/handbook/speedhub/workshop/splined-carrier-conversion

Deviating from the current chainline "might" cause the Chainglider to rub on the seatstay, less risk of this with the #8540s.

steve216c:
Although I reckon I could have squeezed up to 15,000km on this combo of sprocket and chain, I decided to replace all the running gear yesterday as I wanted to investigate an annoying creak on my UN-BB55 bottom bracket that had covered only around 5,000km. It wasn't wobbling, and after checking it wasn't the pedals, realized that the crank would have to come off for further investigation.

Turns out the BB had simply loosened itself by an estimated 1/32 of a turn. A quick tighten, and creak was go. So my spare is back in the box for when it is really needed.

While I would have loved to have pushed this experiment a bit further, I've been plagued with medical matters since Christmas and am about to go under the knife for the 5th time in as many months in the coming days. So I decided to get it all changed now while I have my strength, so bike has no expected upcoming maintenance expected- hopefully until the next oil change.

The reversed sprocket, chain wheel and chain managed a proud 14,027 km recorded. The first 5,000km were exposed, after which I bought a Chainglider. I believe a lot of wear occured pre-Chainglider due to riding in all weathers and commuting on an unpaved forest path which threw up a lot of debris. I suspect the same combo with Chainglider from the offset would not have worn out so quickly. I did need to shorten my chain by a couple of links due to chain stretch. But got over 3,000km out of the shorter chain. I did notice a couple of times where the chain slipped as the sprocket got 'rounder' and I had begun to need to adjust my rear slider (no eccentric as not a Thorn!) every 600-800km to stop the sliding/jumping.

What did I learn?
1) I was unable to use my chain whip to hold the sprocket for removal as there was little for it to grip against. Nothing a bike shop and a EUR 10- donation couldn't fix. They had to extract the sprocket for me with better quality tools. So if you plan to run your cog down- be prepared for difficulty removing unless you are running a splinted carrier.

2) The whole running gear was getting audible towards the end. Not loud, but that might have bugged some of the purists. The chain no longer sat flat on the chainwheel due to the elongation, and I believe the noises riding was probably friction on the chainwheel struggling with a stretched chain

3) There was some mystery wear on the hub exterior itself. I don't recall if that was there when I purchased the bike. Biks shop suggested it could have been if the chain had been slipping on and off causing a groove to form. Or it might have been the Chainglider with the wrong size Chainglider rear end fitted? When I fitted the new parts, I struggled to see where the Chainglider might have rubbed. The bike shop had a look too and agreed the Chainglider end was in fact correct for the sprocket. Perhaps the chain had been slipping onto the hub and back onto the sprocket (the slipping I had occasionally had?) They were not sure. But I will touch up the groove with some black paint to help me spot if it starts wearing again as a safety precaution.

4) Is it feasible to travel around the world on a Rohloff without needing to purchase new chainwheel or sprocket? https://en.wikipedia.org/wiki/Around_the_world_cycling_record suggests 29,000km would need to be covered. I think it is not unreasonable to believe it possible to get 30,000km+ from a new chain/sprocket/chainwheel if you can keep debris from accelerating chain wear (e.g. Chainglider). So in your pannier of tools to take on the journey, only a spare chain would be needed for when you flipped the sprocket the first time.

Finally- some pics of the worn components:




Having fitted brand new replacement components, it is like a brand new bike feel (albeit with a well run in Rohloff hub). It didn't ride badly before, but it rode beautifully on my 10km test run yesterday. Having said that, it just shows what a marvel the Rohloff system is when you can get a chain/sprocket/chainwheel combo costing approx GBP 50- to take you half way around the world. I'd estimate for the same distance using my derailleur bikes I would have spend 10x that on replacing worn components- notomention more lost hours on repairs/maintenance than the Rohloff would need.

Hats off to this robust and amazing bike innovation which does not cease to impress me and many of you guys too!

energyman:
Anybody got any long distance data on a belt ?

JohnR:

--- Quote from: energyman on May 03, 2022, 03:09:41 PM ---Anybody got any long distance data on a belt ?

--- End quote ---
There's a comment at https://bikerumor.com/gates-belt-drive-goes-long-with-new-cdxexp-high-mileage-sprockets-plus-cheaper-cdn-models/ from someone who travelled 31,000km before the belt broke. However, I wouldn't want to embark on a long journey without a spare as I have a vision of some sharp object getting tangled in the belt and triggering premature failure. Fortunately, it's no longer a worry as I recycled my belt drive bike.

Andre Jute:
14K is already a most impressive mileage on a single chain, Steve.

I donít think much of the theory that the channel in the Rohloff was cut by a slipping chain running on and off the cog. Not impossible, I suppose, but Iíve never heard of such an event.

I think it is more likely that you when you bought the bike you had such stars in your eyes that you never noticed the previous owner had been careless.

When I was a young man, my girlfriend used to say I bought cars with my eyes closed, so I know the feeling of discovering the blemishes laterÖ

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