Author Topic: Dumb question - conversion from a Rohloff to derailleur system ...  (Read 383 times)

Undermanager

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I'm struggling at the moment to get past dealing with any major problems with the Rohloff in third world countries, in a way that wouldn't be a trip-ender for a derailleur system. If you had a Thorn Nomad Mk1 with a Rohloff and it failed catastrophically in a far flung third world country, could the Nomad Mk1 bike be converted to take a front and back derailleur system at the local bike shop, or were the frames designed specifically for the Rohloff? I haven't been able to find a Mk1 frame spec online!

« Last Edit: July 30, 2019, 10:03:34 PM by Undermanager »

mickeg

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Re: Dumb question - conversion from a Rohloff to derailleur system ...
« Reply #1 on: July 30, 2019, 10:04:58 PM »
There is no rear derailleur hanger on the Nomad Mk I or Mk II frame, designed for Rohloff.

You might be able to fit an emergency hanger to a skewer, I have never used one of these but maybe it would work with a different wheel.
https://problemsolversbike.com/products/drivetrain/universal_-_21655

I can't imagine anything on the bike that would stop you from fitting a front derailleur.

But I would be really surprised if you could not get the Rohloff shipped for repair unless you were in a place like N Korea.

macspud

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Re: Dumb question - conversion from a Rohloff to derailleur system ...
« Reply #2 on: July 30, 2019, 11:32:52 PM »
The first Thorn Namad is/was a derailleur bike. Then came the Thorn Raven Nomad mk1 which is/was designed for a Rohloff. This has in the past caused misunderstandings between the Nomad and the Raven Nomad both sometimes being called the Nomad mk1. 
« Last Edit: July 30, 2019, 11:35:58 PM by macspud »

PH

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Re: Dumb question - conversion from a Rohloff to derailleur system ...
« Reply #3 on: July 31, 2019, 02:18:16 AM »
I think a more likely scenario would be something that breaks the frame and not being able to fit the Rohloff in standard dropouts without extra parts.   
But IMO you're worrying needlessly, there's so many possible failures you won't be able to prepare for them all and a catastrophic Rohloff failure is way down the list.  In the unlikely event of a total hub failure, you might find a Nexus or Alfine 8 available locally, or have one shipped across the world and still have change out of £200, and I know they fit straight in a Thorn frame. 

Danneaux

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Re: Dumb question - conversion from a Rohloff to derailleur system ...
« Reply #4 on: July 31, 2019, 05:00:19 AM »
Quote
If you had a Thorn Nomad Mk1 with a Rohloff and it failed catastrophically in a far flung third world country, could the Nomad Mk1 bike be converted to take a front and back derailleur system at the local bike shop, or were the frames designed specifically for the Rohloff?

Except for some frame detail changes (i.e. sus-fork compatibility), my 2012 Nomad's drivetrain is essentially the same as a Mk1's so the following suggestions should work for you with one exception: I chose to have the disc brake cap fitted to the left side of the hub to "future proof" it so I more easily convert to a rear disc brake someday. This allows an additional emergency option I will detail below.
-----
Initially, I shared your concerns because I often ride in the remote parts of America's Great Basin deserts and Oregon's Cascade, Coast and Calapooya mountain ranges, Nevada's Pueblo and Ruby mountains, and northern California's Warners where there are no bike shops and those around the periphery have only the most basic supplies. I have also ridden pretty extensively in Eastern Europe and found shops there often stock only the most basic supplies and even things like 26in touring tires can be hard to find outside the larger cities, though you can usually count on finding a 26in knobby of Chinese or Russian manufacture.

Early in my Rohloff days, I carried one of these: https://problemsolversbike.com/products/drivetrain/universal_-_21655 . Coupled with a thumbshifter/clamp-on downtube shifter or bar-end shifter, some cable ties, a long run of cable housing and a rear wheel with a freewheel or freehub from even the most basic bike shop, it would allow fitting a rear derailleur. Unlike some emergency derailleur hangers, the Problem Solvers one has a couple of grub screws that can be threaded in from the back side to catch on the dropout's edge to prevent the hanger from rotating around the hub's quick release until it is tightened. The hanger itself replaces the quick-release nut, so the grub screws are more a convenience than a necessity when fitting the derailleur and hanger to the bike before the hub q/r is closed.

As for the front, it is possible to fit a front mech and its own shifter to match the rear -- I did both as a trial and managed to get good shifting in my workstand when I had the same concerns as you. Depending on your crankset, you might need to replace the crankset's chainring sleeve nuts and bolts to accommodate a second chainring and your crankset might not have the inner lands to mount a third chainring. My Nomad has a 73mm wide BB shell and some front mechs don't have the range to fully shift across a triple crankset unless they are designed for a BB shell of this width. A wide-range "1x" setup with no front derailleur would make a more straightforward conversion.

I also found a small 4-bolt chainring can be fitted to mounts on the disc-specific left hand Rohloff hub cap if the hub is so equipped, allowing the bike to be used as a fixed-gear in case the hub's innards pack it in entirely. To do this, the hub must have the external shifter; the disc cap cannot be fitted if the hub has the internal shifter. The chainline is close enough to work when the wheel is removed and reversed left-for-right in the frame's dropouts. In field use, the eccentric can be shifted laterally slightly to improve chainline. Riding Fixed means you cannot coast, so that is something to keep in mind. I ride my fixed-gear road bike a lot even off-road, so this is not so foreign to me. If things really went bad, riding Fixed sure beats pushing a loaded tourer over some distance.

Of course, I always carry an 8mm socket wrench (one is part of the stainless multitool supplied with my Nomad that also includes a pedal wrench/eccentric bolt wrench and pin wrench) so I can manually change gears on my externally-shifted Rohloff in case a cable lets go. I also carry spare cables, cutters, and a little brass tube to size a replacement cable for making a replacement at a more convenient time.

Echoing PH, over time my confidence in the Rohloff drivetrain has  grown so now I generally leave the PS Universal Derailleur Hanger home, though I will still sometimes fit the chainring to my hub's disc mounts...depending in where I may be traveling. Some of the roads I ply are traveled by car only once every six months to several years according to the District ranger stations, so it can be important for my peace of mind to have a backup I know will get me out in the worst of breakages. Knock wood, so far I've had no problems of any kind with my Rohloff drivetrain.

I don't think you'll ever find it necessary -- because it is so unlikely a Rohloff drive will pack in completely --  but yes, in my experience it is possible to fit a rear derailleur or other emergency drive option to a Mk2 Nomad and it seems likely you could do the same for a Mk1.

Best,

Dan.

Undermanager

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Re: Dumb question - conversion from a Rohloff to derailleur system ...
« Reply #5 on: July 31, 2019, 09:36:54 AM »
Thanks for the thoughts here. I must admit Iím really struggling to be 100% convinced about getting internal gearing. With my (ex) engineer of yesterday hat on, everything fails eventually. I know I can deal with any derailleur problem anywhere in the world but not any Rohloff problem and it makes me nervous. Having spent the last few days reading as many blogs and experiences as I could find, they sound great, a lot of people have good experiences and thereís been a brilliant marketing exercise done on them. But bulletproof they are not, with a small but not insignificant number of riders having problems that required units being sent back to Germany. I canít help thinking that this is fine if you are touring the developed world but I can see major problems if venturing further afield and a problem develops.

Interesting, that about a quarter of long distance riders in this database went for them, and three quarters didnít:

https://thenextchallenge.org/ldcj/
« Last Edit: July 31, 2019, 09:40:22 AM by Undermanager »

Dave Whittle Thorn Workshop

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Re: Dumb question - conversion from a Rohloff to derailleur system ...
« Reply #6 on: July 31, 2019, 10:14:30 AM »
Also note the new Nomad Mk3 can take both systems  ;)

mickeg

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Re: Dumb question - conversion from a Rohloff to derailleur system ...
« Reply #7 on: July 31, 2019, 03:24:28 PM »
...
I must admit Iím really struggling to be 100% convinced about getting internal gearing. With my (ex) engineer of yesterday hat on, everything fails eventually. I know I can deal with any derailleur problem anywhere in the world but not any Rohloff problem and it makes me nervous. Having spent the last few days reading as many blogs and experiences as I could find, they sound great, a lot of people have good experiences and thereís been a brilliant marketing exercise done on them. But bulletproof they are not, with a small but not insignificant number of riders having problems that required units being sent back to Germany. I canít help thinking that this is fine if you are touring the developed world but I can see major problems if venturing further afield and a problem develops.
...

I find it interesting that the designer of the Rohloff decided to build up an internal geared hub after having a bad day with a derailleur system.

I am a retired engineer.  And I was not nervous about buying a Rohloff bike.  But I rely heavily on reputations for things that I am buying.  When a small number of catastrophic failures are reported, I expect that because everything mechanical will have a few defects leave the factory.  But I also assume that those that had the failures will be very vocal everywhere they can about their problems, thus I expect expensive inconvenient failures to be well publicized.

Have you read or at least skimmed through this file? 
http://www.sjscycles.com/thornpdf/ThornLivingWithARohloff.pdf

You might have found this one, but this one appears to be six years old, the one above is more recently updated.
http://www.sjscycles.com/thornpdf/ThornLivingWithARohloff_LoRes.pdf

I am not trying to convince you to buy one, I am just describing my own opinions and experience as I really do not care what you buy.

First photo is my Nomad in Iceland in 2016.  Iceland is not a third world country, but if I had a Rohloff failure where I took the photo, the nearest bike shop was several hundred km away.  Second photo, I was using my Nomad as a mountain bike because I do not have a mountain bike for this sort of riding.  Third photo, the tool kit that I took on my last tour, five weeks in Eastern Canada.  The tool kit includes a lot of shop sized tools because to carry my bike in the S&S case, I have to almost completely disassemble it, which includes pulling both crank arms off, I would rather carry a bit more weight and volume in tools to avoid the almost guaranteed frustration with a mini tool.  I also carry spare cables, nuts, bolts, brake pads, etc., that are not in the photo.  And the 4th photo is my spare tubes and patch kits.  Spare spokes and nipples are in the seatpost, not in a photo.


PH

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Re: Dumb question - conversion from a Rohloff to derailleur system ...
« Reply #8 on: July 31, 2019, 05:08:17 PM »
Interesting, that about a quarter of long distance riders in this database went for them, and three quarters didnít:
https://thenextchallenge.org/ldcj/
I don't know what it is about engineers, but they're often keen on data without understanding it needs analysis to give it value ;)
We don't know why three quarters didn't choose IGH, but we can make some deductions:
Those who's trips were before Rohloff was a known entity are less likely to have used internal gears
Those who had a limited budget are likely to have economised on the equipment
Those who have a preference for drop bars are less  likely to choose a gearing system that only offers a twist shifter

Of those left, there a likelihood that many made the trip on an existing bike, rather than purchase one specifically, so all the above may act in retrospect.  I'm sure some of them chose derailleurs on the basis that they wanted equipment they felt comfortable servicing, I'm equally sure that some will have chosen a Rohloff because the need for servicing was less likely, we don't know how many of either.

I bought a Thorn Raven when I was looking to buy a bike, I considered others and chose that.  Data from a tour in 2002 would put me on a derailleur bike, and from 2004 on  Rohloff. 
« Last Edit: July 31, 2019, 05:12:50 PM by PH »

Andre Jute

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Re: Dumb question - conversion from a Rohloff to derailleur system ...
« Reply #9 on: August 01, 2019, 01:21:02 AM »
Interesting, that about a quarter of long distance riders in this database went for them, and three quarters didnít

Considering how new the Rohloff is compared to the derailleur system, and how much it costs, I'm amazed that as many as a quarter, one out of every four, of intending world circumnavigators chose it. If I didn't have a Rohloff myself, I would think them absolutely nuts to risk so much on something so new. So far I'm in agreement with the OP.

But the fact of the matter is that so unexpectedly many presumably experienced cyclists did choose the Rohloff, and that very few of them, considering the conditions they faced, had any trouble, and that it was in the largest majority of cases speedily handled, inclines me to think that for a new expedition bike, the Rohloff must be the automatic choice.

I take PH's point that people with an existing bike will inevitably tour on a derailleur transmission. There is also the further point that the Rohloff is a singleton product, representing 25% of the touring transmissions by the OP's testimony, while the derailleurs will be spread across many manufacturers, with perhaps only Shimano having a bigger share of the total than Rohloff. That is, Rohloff may well be the most popular transmission for world tourers, or the second most popular, which would turn the OP's popularity consideration on its head. Not that I'm in favour of making a decision so pregnant with possibilities for ruining the tour of a lifetime on popularity (which in many cases is too closely related to price to be meaningful), but it is one way of limiting the field of choice.

If the Rohloff is already on 25% of circumnavigators' bikes, we're already at the point, or will shortly pass it, where the Rohloff is so preponderant on the bike of a serious tourer that it will be, by the OP's logic as well as mine, the axiomatic, automatic choice.

mickeg

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Re: Dumb question - conversion from a Rohloff to derailleur system ...
« Reply #10 on: August 01, 2019, 03:01:13 AM »
I would not be surprised if the Pinion 18 becomes a strong competitor to Rohloff for expedition cyclists.  I see no reason to change from a Rohloff, but if someone had not picked what they wanted to use yet, they would have to compare the Pinion 18 to the Rohloff, each has advantages.

energyman

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Re: Dumb question - conversion from a Rohloff to derailleur system ...
« Reply #11 on: August 01, 2019, 03:06:09 PM »
My question is, why bother ?
Next to sliced bread the Rohloff is one of the 8 wonders of the modern world.