3/11/14 12:21 PM

The "weak link" of my otherwise awesome Tout Terrain winter commuter is definitely the chain management system. Rohloff hub, so it's just a straight chain between a single chainwheel and cog. When it stretches a bit, it will derail over bumps (I ride over many even when it's not pothole season). Vertical dropouts, with a bb eccentric which in theory allows you to tighten the chain. But last time neither I not the shop could budge the eccentric, so we just replaced the chain. In the last week or so I noticed the chain looking a little loose, and sure enough riding back from lunch today I bounced it off twice riding through water filled potholes. So I guess it's a new chain this weekend. Cheap fix anyway (I centainly don't have to worry about an expensive chain on this bike...)

And I kind of like the simplicity - no need to measure, etc.: chain bounces off, replace it.

3/11/14 1:05 PM

Dan--might a simple chain tensioner do the trick? How many miles on that particular chain?

3/11/14 1:08 PM

would an AL chainring floating a mid ship do it. it should stay in the middle

3/11/14 2:35 PM

If you can't get the eccentric to move, you can use a ghost ring to maintain chain tension provided the chainstay gives you sufficient space to fit one. If you don't have a suitably small chainring, a large single cassette or freewheel sprocket should do the trick.

3/11/14 2:46 PM

And it will look truly cool in the process!

3/11/14 6:55 PM

quote:

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neither I not the shop could budge the eccentric

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3/11/14 7:03 PM

Ghost ring, what I meant, did not know that term. Put some reflective tape on the 'ghost ring' and send us a pic from the side at night with headlights on it. ;)

Try ammonia. Assuming the eccentric part in the frame is Aluminum. Or if it is steel and the frame is AL, etc.

3/12/14 6:14 AM

Cool idea indeed, but I think a fat chainstay running under the chain takes that out of the picture. Not sure how a chain tensioner goes on with the Rohloff. And the eccentric is just too eccentric for me (recently saw where one builder said they just weren't going to mess with them anymore).

Well, the chain gets winter duty so it's not exactly pristine anyway.

3/12/14 6:37 AM

For the tensioner, I was thinking you could clamp a mount to the chainstay, then use part of something like the one shown here (image linked from Sheldon Brown's pages):



You might have to build something, but it doesn't look all that hard. You should be able to adapt a different SS chain tensioner to do the job.

3/12/14 6:53 AM

But harder than changing the chain...:)

3/12/14 7:11 AM

I'll give this some thought:

http://www.chainreactioncycles.com/us/en/brand-x-chain-tensioner/rp-prod10137

No matter how esoteric the question, there's usually an answer here on TTF!

3/12/14 9:36 AM

quote:

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No matter how esoteric the question, there's usually an answer here on TTF!

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3/12/14 11:03 AM

The Rohloff I have on Sally's hard tail mtb has no tensioner (got lucky with cog/ring and chainstay length) so it's the ultimate in simplicity which I love. BUT, same as you Dan, when the chain gets a little stretched it will jump off, so that's when it gets changed. Trust me, changing chains is far better than having some kind of chain tensioner...just keep it simple stu.... I've got a whole collection of tensioners sitting in my basement which I have learned to hate.

My mtb has rear suspension so it has to have a tensioner, turns out the only one which worked well was the one from Rohloff.

3/12/14 11:52 AM

That reinforces all my instincts.

3/12/14 12:08 PM

"collection of tensioners sitting in my basement which I have learned to hate."

There you have it really... ;)


Don't track cogs have taller teeth? hint hint. keep it from coming off?

3/12/14 4:59 PM

Track cogs, yeah not a bad idea except such a thing would not go onto a Rohloff hub, it's cogs are proprietary and screw into the hub.

3/13/14 1:47 AM

I run my Rohloff hub touring bike with the Rohloff chain tensioner. The frame was designed for a standard derailleur setup and has vertical dropouts, so there is no way of adjusting the chainring-sprocket spacing. To stop the chain occasionally coming off, I fitted an old front derailleur with the stops completely screwed down - seems to handle the job perfectly, as the chain has never come off since I fitted it. It can just be seen in this photo:

3/13/14 5:42 AM

That might be the ultimate solution; set it up once and forget it.

3/13/14 6:12 AM

quote:

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Rohloff hub, it's cogs are proprietary and screw into the hub.

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3/13/14 7:39 AM

Yes Brian, I have seen Rohloff's run with belt drive, not sure if it's Rohloff who does the 'cog' or the belt drive people.

For basic commuting a less expensive but very similar set-up can be had directly from Trek in the way of a complete bike called the Soho. Iit has belt drive with an 8 speed Shimano hub, drum rear brake and disc front brake, proprietary FULL coverage fenders, all for about the price of the Rohloff hub by itself. Got Sally one of these a few years ago, set it up with low narrow straight bars and a -17 stem so at least she could be a little more aero than sitting completely upright. She says it's still a slow bike but it sure is good and maintenance free over the long run in all weather...that said I wont let her ride it in the winter, that's what an old single speed coaster bike is best suited for.

3/13/14 1:58 PM

The Rohloff cogs are reversible - they are symmetrical, have a multiple thread (so the lead is greater than the pitch), and come off fairly easily. So when the teeth start developing a bit of a hook, by turning the cog around you get a (not quite) new cog.

4/22/14 4:31 PM

This turned out to be more complicated than I realized. Got a new chain, but then noticed some grinding noise when I pedaled hard. A little googling confirmed my idea that the cause is a worn cog. As Nick pointed out, with a Rohloff cog you can flip it and then wear out the other side. But first you have to remove it. To do that you need a Rohloff removal tool and chain whip. Had the whip, bought a tool. Then, with all my awesome strength, I can't budge the friggin' thing. Dripped in liquid wrench, still no go. Took it to the LBS, they eventually got it off after dripping in some Finish Line stuff. Now the bike is back together and running smoothly. Possibly running the bike through three winters had to do with the recalcitrant cog.

We can now use the eccentric, but the chain needed to be replaced anyway.

After using this bike for commuting/errands, other bikes just don't make it. The Rohloff hub, generator lights, 2 big Carradice bags, fenders, discs, get it done. I am spoiled.

4/22/14 4:54 PM

I don't know what chainring you are using but Surly sells stainless steel chainrings in 130 and 110 BCDs and a wide range of tooth counts that have no shaped or ramped teeth so they are less likely to derail the chain. They don't shift as well as a modern enhanced chainring but that's exactly what you want.

4/22/14 5:23 PM

At times the chain stayed on the ring and came off the cog. I just let the chain go too long. When the LBS guy pulled out his pocket chain gauge, it was way gone. Easy enough to change a bit sooner.

4/23/14 12:08 PM

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