Increasing chain/sprocket/chainwheel life on Rohloff/hub gear drivetrains

[Andre Jute]

I guess what I’d really like to know is how long I can leave a chain on for until it becomes a problem.

I recently asked Rohloff that question and was told that the standard limits that apply to derailleur equipped bicycles also apply here.  I tried debating the point with them but go nowhere.  I also didn’t get a lot of reasoned response to my arguments...

Peter

I haven't worn out a chain on a Rohloff, but I wonder whether the answer isn't, as so often, "It depends." And what it depends on in this case is whether you have a chain tensioner or a completely different manner of driveline length adjuster to compensate for chain elongation.

ROHLOFF WITH EXTERNAL CHAIN TENSIONER
If you have a chain tensioner in your Rohloff setup, the same reasoning applies to your chain as in a derailleur setup: if the chain is elongated by 1/16in, chuck it but the sprocket and chainwheel can be kept if still good; if the chain is elongated by 1/8in, it has gone too far and chain, sprocket and chainwheel must all be replaced. That rule was invented for use with sensitive derailleurs with many different sized chainwheels and sprocket, with chain slack between all gears, and in all gears except perhaps one, which has to be taken up by a spring-loaded chain tensioner. But many bodged-up Rohloff installations, and most on bikes with suspended back ends, also have chain tensioners, and the same logic applies.

ROHLOFF WITH FRAME-SIDE DRIVE LINE LENGTH ADJUSTMENT
If you don't have a chain tensioner on your Rohloff setup, which is usually because there is another means of setting chain tension, most commonly either by slider rear end or by eccentric bottom bracket, it doesn't matter whether the chain elongates as long as you take care to put the chain back in phase with the sprocket and chainwheel whenever you disassemble it for any reason. "In phase" means that you don't move the chain one tooth with reference to the teeth, so that the same teeth engage the same chain links for the life of the components. (Sheldon Brown, no fool, marked driveline position by grinding a little off the top of a tooth that would fall into an inner link in the chain.) Thus chain, sprocket and chainwheel all wear in phase and *any amount* of elongation in the chain is adjusted by moving the sprocket further from the chainwheel by sliding the sprocket away in the slots or moving the chainwheel forward by turning the eccentric bottom bracket holder in the bottom bracket shell. The limit of chain life is now set by the teeth becoming so worn that the chain starts skipping, at which point a new chain is fitted complete with new chainwheel and sprocket (except if they're reversible, in which case they're reversed and the new chain "thinks" they're new). This scheme works best for sprockets or chainwheels with an even number of teeth.

VERY ADVANCED CHAIN ELONGATION
Theoretically, for very advanced chain elongation, a new range of adjustment can be acquired by removing one link from the chain and resetting either the rear axle in the sliders or the EBB in the bottom bracket shell to the zero position. But the elongation would have to be almost a whole inch! I think this is an unlikely scenario, as other parts of the chain will start breaking before then, but mention it because of the extreme mileages on single chains that some posters have reported here.

***

I say once more: This is pure reasoning. I'm planning on trying it but don't have enough miles on my Rohloff-equipped bike yet.

***

I take y'all know that a chain on a hub gear installation and particularly on a Rohloff must have considerable slack, an absolute minimum of 5mm top and bottom, so a minimum of 10mm, or it will wear itself and all related components abnormally fast.

Andre Jute
 http://www.audio-talk.co.uk/fiultra/BICYCLE%20%26%20CYCLING.html

[Cake]

I would have have thought that as long as the chain is running straight (Rohloff, fixed, SS for example) the method of tensioning it would have little effect on the long term wear of the chain.  Run it as long as you dare!

Putting the chain back on in the same place as it came off is pretty much essential (for gear train longevity) - as i have found out from experience.  The setup sounds quite unhappy if it is not, although it is possible to take it off and get it running quieter by trial and error.

How do people get this correct when changing a puncture for example?  I would be tempted to cable tie the chain to the chainring, but i would have to think about how to make sure the sprocket was back in the correct place, chain wise.

I have found that the chain tension changes quickly with use - a tight chain doesn't remain tight very long with use. but a really tight chain is bad news for bearings!

Interesting.

[vik]

As Sheldon Brown notes using even number of teeth on cog and chainring will allow for maximum chain life:

http://www.sheldonbrown.com/chain-life.html

Beyond that on a bike with horizontal dropouts or an EBB I'd just run the chain until there is a problem...then throw the chain out and flip the cog/ring around and install a new chain.

As long as the pedals turn the cranks there isn't much else to be fussed about.

[vik]

Putting the chain back on in the same place as it came off is pretty much essential (for gear train longevity) - as i have found out from experience.  The setup sounds quite unhappy if it is not, although it is possible to take it off and get it running quieter by trial and error.

How do people get this correct when changing a puncture for example?  I would be tempted to cable tie the chain to the chainring, but i would have to think about how to make sure the sprocket was back in the correct place, chain wise.

Assuming you use even number of teeth on the cog and ring then all you have to do is get the chain back on in the correct position choosing from one of two options [inner or outer plates].  An easy way is to file down the top of one tooth on the cog and ring slightly choosing either both that sit between the inner or outer plates on the chain.

[sbseven]

Beyond that on a bike with horizontal dropouts or an EBB I'd just run the chain until there is a problem...then throw the chain out and flip the cog/ring around and install a new chain.

I'm still not convinced that's the only or even the cheapest way...

UK prices of Thorn's 'stock transmission components' -
Rohloff Sprocket 16T: £25
Thorn Chainring 104mm PCD 4 Arm 38T: £30
KMC Z51 (Thorn current 'stock chain' on new builds): £4

Scenario 1: Beat the transmission to death, clock up 96,000km
Operation: Run chain for 16,000km then turn sprocket/chainring and add new chain, change everything at 0K, 32K, 64K, 96K km
Cost at 96,000km: 4*Sprocket + 4*Chainring + 7*Chain = £248

Scenario 2: Look after the transmission, clock up 96,000km
Operation: Run several chains in rotation (e.g 4 for each 24K, rotate in sequence every 2000km), turn sprocket/chainring at 24,000km, change everything at 0K, 48K, 96K
Cost at 96,000km: 3*Sprocket + 3*Chainring + 17*Chain = £233

Rational behind Scenario 2:
Most Sprocket/Chainring wear occurs towards the end of a chain's life, once it's stretched beyond 1/16" in 12". By changing the chain before this point and using chain rotation, the sprocket/chainring should last quite a bit longer and therefore won't need to be changed so often. (Sprocket/chainring rotation at 24,000km under this regime, might even be conservative, perhaps. I don't know??)

Notes:
1. It's the price differential between sprocket/chainring and a (cheap but adequate) chain that is the deciding factor.
2. Under Scenario 1, if you're unfortunate to break a chain, you may have to buy a sprocket and chainring early, possibly adding to the cost.

I'm not advocating either scenario particularly (and scenario 2 isn't proven AFAIK or even practical on a long tour), but submit this into the discussion!

Shaun

[vik]

I'm still not convinced that's the only or even the cheapest way...

UK prices of Thorn's 'stock transmission components' -
Rohloff Sprocket 16T: £25
Thorn Chainring 104mm PCD 4 Arm 38T: £30
KMC Z51 (Thorn current 'stock chain' on new builds): £4

Scenario 1: Beat the transmission to death, clock up 96,000km
Operation: Run chain for 16,000km then turn sprocket/chainring and add new chain, change everything at 0K, 32K, 64K, 96K km
Cost at 96,000km: 4*Sprocket + 4*Chainring + 7*Chain = £248

Scenario 2: Look after the transmission, clock up 96,000km
Operation: Run several chains in rotation (e.g 4 for each 24K, rotate in sequence every 2000km), turn sprocket/chainring at 24,000km, change everything at 0K, 48K, 96K
Cost at 96,000km: 3*Sprocket + 3*Chainring + 17*Chain = £233

Rational behind Scenario 2:
Most Sprocket/Chainring wear occurs towards the end of a chain's life, once it's stretched beyond 1/16" in 12". By changing the chain before this point and using chain rotation, the sprocket/chainring should last quite a bit longer and therefore won't need to be changed so often. (Sprocket/chainring rotation at 24,000km under this regime, might even be conservative, perhaps. I don't know??)

Notes:
1. It's the price differential between sprocket/chainring and a (cheap but adequate) chain that is the deciding factor.
2. Under Scenario 1, if you're unfortunate to break a chain, you may have to buy a sprocket and chainring early, possibly adding to the cost.

I'm not advocating either scenario particularly (and scenario 2 isn't proven AFAIK or even practical on a long tour), but submit this into the discussion!

Shaun

The price difference between Scenario 1 and Scenario 2 is £15 for 96,000kms or £0.0002/km.  If you broke a chain under Scenario 1 pop in a powerlink to reconnect the chain and get back on your bike.

Personally for that cost differential I'll take the lazy option that doesn't require storing, organizing and swapping multiple chains.

[vik]

Come to think of it...using even # of teeth on cog and ring as well as a chaincase probably would net you the longest chain/cog/ring life for the least cost over a distance of 96,000kms.

http://www.thorncycles.co.uk/forums/index.php?topic=2467.0

[Cake]

Assuming you use even number of teeth on the cog and ring then all you have to do is get the chain back on in the correct position choosing from one of two options [inner or outer plates].  An easy way is to file down the top of one tooth on the cog and ring slightly choosing either both that sit between the inner or outer plates on the chain.

If i had thought about it at the time a small indentation using a centre punch while the sprocket was off would also do the trick...

[stutho]

Personally for that cost differential I'll take the lazy option that doesn't require storing, organizing and swapping multiple chains.

put me down for that plan too!

[sbseven]

Come to think of it...using even # of teeth on cog and ring as well as a chaincase probably would net you the longest chain/cog/ring life for the least cost over a distance of 96,000kms.

http://www.thorncycles.co.uk/forums/index.php?topic=2467.0

I'd forgotten about that option!

[stutho]

I should add that the lazy option got me more like 12000miles from my first chain.  When I swapped it it was because chain ring was starting to look very worn.  I am now at about 6000 miles on chain number 2  (still with the same chain ring) and every thing is looking good for at least another 6000 miles

Stuart 

[sbseven]

My comments on the alternative scenario were more theoretical than practical! I mentioned it as more a point of discussion.

I'm still wondering, though, how far you could actually get a sprocket/chainring combination to go by using cheap chains and regularly changing them before they wear to "protect" the more expensive components. It might be a surprisingly high figure...

[stutho]

I'm still wondering, though, how far you could actually get a sprocket/chainring combination to go by using cheap chains and regularly changing them before they wear to "protect" the more expensive components. It might be a surprisingly high figure...

I have no doubt that you are correct - You will get EVEN better mileage to the £ using chain rotation. (I am just to lazy )

I suspect the best mileage/£ of all will come from a sealed drive chain - I would really like to know how many miles you could get from a chain (run into the ground) in such a system.   I wouldn't be surprised if it was  30,000+miles from a single chain - maybe even more!   

[travelling]

I can't help but notice no one is mentioning oiling and adjusting the chain?

on my motorcycle using the ..can i be arsed to oil it with wax when i remember it lasts about 8,000 miles

using the scott oiler automatic lube it normally lasts about 32,000 miles with regular adjustment

surely regular and proper maintenance is one of the cheapest things to a long chain life?

[Andre Jute]

I suspect the best mileage/£ of all will come from a sealed drive chain - I would really like to know how many miles you could get from a chain (run into the ground) in such a system.   I wouldn't be surprised if it was  30,000+miles from a single chain - maybe even more!   

Maybe. I don't do your mileage but i haven't had a lot of luck with your scenario on my two Shimano hub gear bikes. Shimano Nexave aluminium chainwheels and sprockets in fully enclosed Dutch style chaincases and well-serviced gave up the ghost at lesser mileages than the one at which my Rohloff/Country/steel drivechain still appears new. I can't understand why Gazelle and Trek fitted those short-service cranksets to commuter bikes.

If I'd known I would be making this comparison, I would have kept proper records of which chain got which treatment (one was deepcleaned at about 900km and then white waxed, the other was just oiled, neither lasted impressively by the standards of anyone else here).

That my Rohloff installation on my Kranich seems to last so much better may be due to any of a number of factors, of which I expect three to be important:

1. Steel drivetrain rather than aluminium.

2. The makers of my Utopia are convinced that an extremely precise chainline, to within 1mm of adjustment, is important for smooth operation of and longevity in the drivetrain components.

3. That the chaincase largely succeeds in keeping out grit. BUT: Having read here of commuters getting many multiples of the chain mileages I achieved on chaincased Shimano hub geared bikes, I'm not persuaded that a chaincase will double your already extensive chain life, or whatever you're hoping for. The fellows who're getting these big mileages on chains must already be doing everything right! I take up the cost-benefit consideration this raises in http://www.thorncycles.co.uk/forums/index.php?topic=2467.0

Andre Jute
We economists are used to back-pedalling