Rohloff questions

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PH
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Re: Rohloff questions

Postby PH » 23 Dec 2020, 7:51pm

531colin wrote:The Rohloff instructions for lacing up are interesting, but I'm sure I would have remembered if they had said to lace up a disc wheel 1 cross all inbound?

That's the Thorn way, apparently they do it with Rohloff's approval. I thought it a bit odd, but as they're offering a ten year warranty against flange failures (Rohloff's is two years) they can do as they like.

Des49
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Re: Rohloff questions

Postby Des49 » 24 Dec 2020, 7:33am

531colin wrote:No secret that this is my first encounter with Rohloff; so what do experienced users think of this thing?

ImageIMG_5323 by 531colin, on Flickr



The cable drum is a bit of a faff, due to not doing it frequently I find myself reaching for Rohloff's instruction manual on this each time. Never had a problem installing or problems in use. I too solder the ends of the cables to avoid fraying, needs to be done without too much solder as then the ends don't fit into the drum. I also coat the whole assembly liberally in grease before putting it into the box.

I change my shifter cables and outers maybe every couple of years, possibly sooner if it becomes too stiff. Using Shimano full length brake outer. But do have a Rohloff set of gear outer and cables ready for the next change.

Only issue I have is that the gear change with the twist shifter is not that light an action, not a problem until you have wet and cold hands, or if really covered in mud I sometimes cannot get enough of a grip. The newer wavey form of grip on the shifter is better. I possibly remember I read somewhere that the spring tension may be lower for gear changes in more modern hubs, would be interesting to hear if this is the case and if it can be changed.

Brucey
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Re: Rohloff questions

Postby Brucey » 24 Dec 2020, 9:12am

one of several annoying features is the cable that goes around that drum. For some reason best known to themselves, Rohloff used 0.9mm dia cable, so conventional gear inner won't work.

The shift detent springs are (IIRC) two small coil springs that are buried in the LH end of the axle, and are exposed (and can be lost etc) when this assembly is dismantled. I don't think it would be a big challenge to come up with softer springs which give a softer detent action.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

PH
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Re: Rohloff questions

Postby PH » 24 Dec 2020, 2:58pm

Brucey wrote:one of several annoying features is the cable that goes around that drum. For some reason best known to themselves, Rohloff used 0.9mm dia cable, so conventional gear inner won't work.
cheers

With the internal shift it is, with the external it's 1.1mm, the pully is very different, much bigger and the cables terminate there rather than wrap around and back to the connectors.
The shift detent springs are (IIRC) two small coil springs that are buried in the LH end of the axle, and are exposed (and can be lost etc) when this assembly is dismantled. I don't think it would be a big challenge to come up with softer springs which give a softer detent action.

I've had to replace these springs, simple enough and only a couple of quid, the shifting had become mushy and it skipped out of gear a couple of times, I was relieved is wasn't anything more drastic. I'm not sure if it's these springs, the different hub models, or general wear, but mine all feel different. I thought the one in the folder was stiff because of the cable routing, but I tried the wheel in another bike (just on the workstand) and it felt the same. The highest mileage one, which needed the springs replacing, has the lightest action, so it may just be that it's worn in?

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531colin
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Re: Rohloff questions

Postby 531colin » 24 Dec 2020, 5:07pm

I'm going to have to think again. The Rohloff twist shifter is harder to move than I had hoped. I had hoped to be able to change gear like this;

ImageIMG_5329 by 531colin, on Flickr

but the shifter is too stiff to turn easily with finger and thumb ends. I think its going to have to go on the stub bit of grip behind the cross-bar.

ImageIMG_5332 by 531colin, on Flickr

(Picture of the bars on a deraillier bike here...https://forum.cyclinguk.org/viewtopic.php?f=1&t=104410&hilit=Jones&start=105)

slowster
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Re: Rohloff questions

Postby slowster » 24 Dec 2020, 6:21pm

You do need a reasonably good grip of the twist shifter to operate it. I'll throw in a few thoughts:

1. It's a pity the twist shifters are so expensive (£80 from SJS), otherwise it might be worth seeing if it would be possible to modify one. The problem is the relatively small diameter of the grip section and its round shape. If it were a much bigger diameter correspondingly less force would be needed to turn it. Looking at your photographs, it strikes me that the ideal would be something like a capstan handle or paddle wheel in place of the rubber grip, with projections/paddles which could be pushed up or down by a finger or thumb with hands otherwise gripping the bars (somewhat similar to a thumbshifter). However, you would probably need to move the stub further inboard in order to have sufficient space for the projections/paddles, i.e. I guess the projections/paddles would need at least a 50mm radius.

Although the above sounds a bit Heath Robinson, I suspect it could work very well: very easy shifting with minimal force from the fingers and thumb, all while maintaining a good grip of the bars.

2. What about putting the shifter on the front part of the bars that you grip? Either at the front with the rotating part of the shifter nearest to you, or reversed and at the other end (so that you would grip it between the heel of your palm and little + ring fingers. I guess one or both of those might not be practical depending upon your hand position when gripping the bars and/or on your brake lever position.

3. FYI there are a few other aftermarket shifters, but they make the standard shifter look cheap and I don't think they would offer you a solution to your particular problem:

https://www.sjscycles.co.uk/gear-shifters/rohloff-shifter-with-full-length-grip-by-hase-in-germany/

https://www.sjscycles.co.uk/gear-shifters/gilles-berthoud-twister-for-rohloff-hubs-black/

https://www.sjscycles.co.uk/gear-shifters/comotion-rohloff-shifter-for-speedhub-50014/

https://www.sjscycles.co.uk/gear-shifters/cinq5-shiftr-thumb-shifter-for-rohloff-hubs-flat-bar-222mm/

Brucey
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Re: Rohloff questions

Postby Brucey » 24 Dec 2020, 7:29pm

FWIW I too am rather put off by all available controls for rohloff hubs, being fantastically pricey, not at all what I want, too complicated, or all three of the above. So I have a cunning plan for a better (better for me, anyway) DIY shifter for Rohloff. Obviously -like many of my most cunning plans- I have not actually finished it yet, but the idea is simple enough and ought to be well within the scope of someone like Colin's fettling skills.

The idea is to take shifter cable pulley #8194 (which costs peanuts)

Image
Rohloff #8194
to mount it on a suitable bearing, and to give it a set of 'paddles' (three or four arms) so that the control has about a 4" diameter in total. A simple bracket will support the bearing and will have gear cable stops (and maybe barrel adjusters) built into it. My plan is to mount this beneath the stem, with the paddles rotating in a horizontal plane such that either hand can be used (eg mainly with the thumbs, but fingers can be used too of course) whilst riding the tops for shifting. This should give at least twice the leverage vs the grip shifter layout, with the further option of using both hands (on one paddle each side) if needs be. Since the pulley can be supported on a proper ball- bearing, there won't be any of the dragginess that bedevils most rotary shifters

I have not figured out the best way of mounting a similar shifter for flat bars, or how best to adapt the design for flat bars either.

Food for thought?

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

brumster
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Re: Rohloff questions

Postby brumster » 24 Dec 2020, 10:00pm

Interesting thoughts Brucey. I've always thought it might be possible to make something similar along the lines of the Suntour Command shifter and mounted for use inside of the brake lever on dropped bars.

slowster
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Re: Rohloff questions

Postby slowster » 24 Dec 2020, 10:25pm

Brucey wrote:I have not figured out the best way of mounting a similar shifter for flat bars, or how best to adapt the design for flat bars either.

How about two such shifters, LH and RH with the upshift cable to one and the downshift cable to the other, with a third cable between them to maintain the desmodromic function? The gear could be changed in one direction by either pulling the LH shifter or pushing the RH one, and vice versa.

Alternatively ratchets could be added to make both levers operated by pushing the lever, i.e. no pulling of the lever, with one shifter for upshifts and the other for downshifts (like Shimano Rapidfire shifters). I think the Cinq 5 Rohloff shifter works like that but without a third cable linking the two shifters, which I presume means the shifters have springs in them to take up the slack when the other shifter is actuated.

Brucey
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Re: Rohloff questions

Postby Brucey » 25 Dec 2020, 7:48am

having two shifters with a linking cable is an interesting idea. However with fixed paddles on, the shifter would be quite large enough already, and having two of them is, er, twice as much stuff on the handlebars as is strictly necessary....? I have considered all kinds of ratchet systems and whilst they would all be feasible in a mass-produced item, in a lower volume item such things may turn into an expensive can of worms (like many of the other rohloff shifters on the market) and/or something that is well outside the shedgineering remit if it is to be DIY-made, leave alone reliable/repairable in the field etc.

It will be interesting to see what happens when a proper bearing is used to support the pulley though; a common moan is that with a Rohloff shifter you have the choice of little backlash and a rather bindy shift, or more backlash and a free-er shift action. It is not clear in my mind if, when the backlash is taken out, the binding comes mainly from preload in the cables or from binding beneath the pulley itself. I guess when I get my finger out and finish the thing I will find out!

cheers
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531colin
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Re: Rohloff questions

Postby 531colin » 27 Dec 2020, 3:30pm

ImageIMG_5333 by 531colin, on Flickr

I'm going to try it like this.
It leaves the full length of the current grip section which is deliberately about the same as brake hoods + ramps on a Nitto noodle bar.
The twist-grip is reasonably easy to access, and has some protection against damage due to falling off etc.

PH
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Re: Rohloff questions

Postby PH » 27 Dec 2020, 6:06pm

If that doesn't work out, this page might provide some inspiration
https://www.cyclingabout.com/rohloff-hu ... andlebars/

Brucey
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Re: Rohloff questions

Postby Brucey » 27 Dec 2020, 7:27pm

PH wrote:If that doesn't work out, this page might provide some inspiration
https://www.cyclingabout.com/rohloff-hu ... andlebars/


the thing that struck me was just how ruddy awful most of those looked, both to the eye and (probably) to actually use.

It gives me hope that whatever I manage to cobble together is unlikely to be any worse than that.... :lol:

FWIW a mount that places the shifter closer to the tops is notably absent from the lost of 23, and shouldn't be difficult to make...? Of the centre-mounted shifters, the thorn mount is arguably the pick of the bunch because it places the shifter forwards of the steerer at a least.

cheers
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