Rohloff drivetrain wear: when to replace chain, sprocket, chainring?

[Chris2020]

Hello, 
I’m a 1st time Rohloff owner. Thorn nomad mk3
5 years old  22000km

Minimal maintenance other than yearly oil change and very occasional cleaning and oiling. No chainglider
EBB at max adjustments. Ie.
chain at the pont when I would need remove links.
I am wondering when would be the point to either replace the chain,  replace or flip the chainring and/or sprocket?
Any advice would be much appreciated.
Thanks
Chris

[UKTony]

I take it from what you say that the slack in the chain has already reached the point where adjustment is necessary but there’s no adjustment remaining on the eccentric.

Rohloff recommend a new chain is fitted after reversing a sprocket.

I don’t know how successful taking a link out of the chain would be because I’ve never done it. If it was me I’d simply flip the sprocket, and the chainring, then fit a new chain.

[JohnR]

I think that with a straight chainline then the chain can be fairly slack without the risk of it coming off. However, if it's a long time since the chain was last replaced then I would first replace the chain (single speed chains are reasonably priced) and see how will it runs. If it isn't happy then flip the sprocket and chainring.

[Chris2020]

I take it from what you say that the slack in the chain has already reached the point where adjustment is necessary but there’s no adjustment remaining on the eccentric.

Yes, and it's come off a couple of times now. The chain has never been replaced. I did buy a replacement at some point but haven't swapped it yet, but from what I understand now would be the time to do so.

[PH]

You might eek out another few thousand km's by taking a link out, but the failure method becomes more and more likely to be a snapped chain.  I'd consider I'd had good value from it. flip both chainring and sprocket and fit the new chain.    I don't always get the same distance out of the second side of a chainring and sprockets, maybe 70%, but yours don't look as worn mine usually do at that mileage.  Even at 70% that's nearly 40k km from a chainring, sprocket and two chains, that'll turn most people running a derailleur green with envy.

[Chris2020]

Thank for your reply. That is kind of the feeling I had but as I’ve never been at this point before, part of me does want to see how long I can get out of one chain. As you say compared to my previous derailleur bike it’s really hard to fathom!

[martinf]

You might eek out another few thousand km's by taking a link out, but the failure method becomes more and more likely to be a snapped chain.  I'd consider I'd had good value from it. flip both chainring and sprocket and fit the new chain.

Agree. After 22000 km and given the wear on the chainring, time for a new chain and flip the sprocket and chainring.

Snapping a chain could be very inconvenient.

On a hub gear bike I have had this happen once, the outer plates on one link failed on a very worn chain, but nothing like 22000 kms use. This was before I started using Chaingliders, which make a significant difference to transmission maintenance and longevity, at least for all-weather use in the coastal area where I live.

Fortunately for me I was only a few kms from home and the bike trailer I was towing had been unloaded before the chain broke. So not too hard to push the bike/trailer up the hills and coast on the downhills. My bike toolkit now includes spare 1/8" chain links in addition to the 3/32" quick links and spare links I already had.

[Andyb1]

Strange how the chainwheel is more worn than the sprocket - but maybe it is alloy while the sprocket is steel?
With teeth starting to hook is there a risk of the chain being sucked up the back of the chainwheel and locking up? 

Out of interest, what make /model of chain is it?    I think Thorn used to fit KMC X1 chains which have a good reputation for long life but were not cheap.

[martinf]

Strange how the chainwheel is more worn than the sprocket - but maybe it is alloy while the sprocket is steel?

If it's the original chainring supplied by Thorn it is almost certainly aluminium alloy.

With teeth starting to hook is there a risk of the chain being sucked up the back of the chainwheel and locking up?

Very unlikely on hub gear without a derailleur or derailleur type tensioner. Even with a slack chain, though with the latter it can drop off the chainring.

[Chris2020]

The chain is KMC E1, original chainring supplied by Thorn 45T and sprocket is rohloff (steel) 19T.

[mickeg]

Put on a new chain, flip the sprocket.  Your sprocket looks amazingly good for that distance and if your chain is worn.  My sprocket was more worn than that when I finally flipped it.

Your chainring looks more worn than the sprocket does, that surprises me.  I would replace the sprocket chainring at this time.

You might consider measuring your chain later.  The cheap small chain checkers are not very accurate, but you can measure the length of an entire chain when it hangs from a hook.  One link is a half inch when new, thus 100 links is 50 inches from center of pin to center of pin.  If it is 50.5 inches, that is one percent elongation.  I think on a Rohloff bike replacing the chain when you are a bit over one percent elongation is a good time to replace it.

EDIT:  I made a correction above, I meant to suggest replacing the chainring, but used the word sprocket inadvertently.

[Andyb1]

The KMC E1 is reputed to be a good chain but not cheap.  It looks like it has done well.  Perhaps helped by your 45 / 19 ratio?
The chainwheel being alloy probably explains the wear - but if you can flip it then it will also do a good total mileage.
If you fit a new E1 and flip both chainwheel and sprocket then in another 22,000 km everything will be due for a change.

[martinf]

The KMC E1 is reputed to be a good chain but not cheap.

I use these for most of the hub gear bikes I maintain. With ChainGliders if possible. My take on this is that the higher price over a standard chain is compensated by longer chainring life (except for Rohloff the costs of rear sprockets are cheap enough to be ignored). Plus less time spent on chain maintenance.

Perhaps helped by your 45 / 19 ratio?

Big chainrings and rear sprockets wear less than small ones. On my Rohloff equipped large-wheel bikes, I have a 19T  on my Raven Sport Tour and a 21T on my Raven Tour. I have 22T on nearly all the other hub gear bikes I maintain.

On small-wheel bikes that generally use 11T to 13T smallest sprockets I found wear was significantly less with slightly larger ones. My Rohloff equipped Brompton therefore has a 15T instead of the 13T usually fitted for small wheel bikes. On this bike another advantage is that the 15T can be flipped to get about double the mileage, whereas the 13T can't be flipped. 

[Andyb1]

The KMC E1 is reputed to be a good chain but not cheap.

I use these for most of the hub gear bikes I maintain. With ChainGliders if possible. My take on this is that the higher price over a standard chain is compensated by longer chainring life (except for Rohloff the costs of rear sprockets are cheap enough to be ignored). Plus less time spent on chain maintenance.

With Rohloff / chainglider I am using cheap chains - Sram PC870.  £15 at Halfords.  It is what was fitted on the bike when new and I now use two PC870 chains which I swop around every 5000 miles……it will take me a few years to wear them both out as their projected life looks around 15,000 miles each……they may outlast me.


Without a chainglider I would definitely fit a better quality chain - like a KMC E1 EPT.  (AFAIK the EPT bit just means it has better rust protection). £30 at Halfords.

[Andre Jute]

The green glow around me isn't Spring bursting out in my study, it is envy of someone who gets 22,000km on a chain.