Rohloff Alternatives to Grip Shift?

[MacB]

Now as far as I can ascertain there are none, I've seen a couple of concept ones but nothing that's reached the market. There are 3 or 4 alternate twist shifters that I've found but it's just a variation on a theme. So it got me wondering about the possibility of a bar end shifter that could also mount on a thumb mount as well. I'm not 100% sure on how the Rohloff one works, or actuall cable pull, so can anyone flesh out, or correct, the following?:-

existing shifter works on a pull/pull system, whichever way you twist it pulls cable in and allows the other cable to be pulled back in turn by the hub end of the mechanism?

the overall amount of cable pull capacity, for each cable, is? I've seen 90mm bandied about for this

if you wanted to model a new shifter on, say a Dura Ace bar end one, then you'd need two cable inputs for starters. Each cable would circle the barrel of the barend shifter in a different direction to recreate the pull/pull idea. The shifter itself would need 13 indexed steps and the barrel/cablewrap bit would need to be of a diameter to allow for the full amount of cable pull, so I'm guessing a bit bigger than normal. could it be any bigger, or worse, than mounting an existing twist shifter on a barend adaptor?

If it could be done for barend then couldn't it be mounted on a thumb shifter, like the Pauls Thumbie, with just the addition of the second cable run? Obviously the thumb mount would need to be shaped to accomodate the diameter of the shifter itself.

One prototype I saw pics of was from Tout Terrain and was a truly humungous disc, like a hockey puck, with a couple of thumb levers on the sides and was hung under the bar. That makes me think that the size was down to the sheer amount of cable to be moved and the diameter required to achieve this. But how far round does the Rohloff shifter move, is it less than 360 degrees? Would a broader but narrower barrel piece work if each cable spiralled a bit?


Reason for all this? idle curiosity really, but would appreciate any info anyone has on this....cheers....Al

[MacB]

Hmm, finally found the right download on the Rohloff webiste, so it's 13 clicks at 7.4mm each, so a total of 96.2mm. By my reckoning, and allowing for the full 360 not being in use, you'd need a diameter of about 35mm, gives you the cable pull required and a spare 14mm or so.

Also ignore my cable spiral nonsense, it has to work within 360 degrees, unless it was a ratchet and return type lever.

[LittleWheelsandBig]

Rohloff shifters aren't indexed, that is done in the hub.

A barend or downtube shifter (or standard thumbshifter) can only move less than 180 degrees, unless it returns to the centre with a ratchet. A multilever thumbshifter could wrap further though. All this means the cable barrel needs to be bigger.

[MacB]

Yep, it's really a thumb shifter I'd be interested in, but I've had a thought and am messing about with some diagrams....it keeps me out of trouble 

[Wowbagger]

Two cables operate the gear changing mechanism, one for changing up, the other, surprisingly, for changing down. I once rode the tandem about 15 miles with a broken cable. I was still able to change gear, by using the twist grip for changing up and the end of the broken cable for changin gdown. The "down" side is far more likely to break as pressure on the pedals makes gear changes difficult and when changing up, of course, your feet tend not to be keeping up with the wheels, so there's little pressure.

It was actually quite hard pulling the broken cable end. I would guess that bar-end or downtube shifters would not work because they hold the derailleur in place by friction and that would put a lot of stress on the cable and your hands.

Alfine and Nexus hubs, OTOH, have just one cable and that is always under tension, which the Rohloff cables are not.

[Kim]

Is there not an electric shifting wossname for the Rohloff?

[Wowbagger]

I hav heard of such things but never seen one.

Edit: ereitis!

[Kim]

That's the one.  I came across it while researching more exotic potential solutions for baraktacycle controls (before establishing that a good quality grip shifter was actually fine).  Lots of posts by people bashing the complexity, overlooking the obvious edge-cases where such a thing would be awesomely useful.  It's always going to be a bit niche.

[andrew_s]

My not-got-as-far-as-a-piece-of-paper design makes use of 2 drop bar shifters, each with an STI/ergo style inner lever. Flap the right lever to change down, flap the left lever to change up (or vice versa).

You'd want a cam cable gripper that gripped the cable when the lever was moved, but let go of it on the return back to neutral, something like a small version of a rope ascender. To change 1 gear on a 30 deg sweep of the inner lever, you'd want the clamp 14mm above the lever pivot. Pulled in cable could just go up a tube in the lever body rather than use a bulky spool. You'd want a little proddler to to hold the clamp open, and an adjustable friction device to prevent cable bounce pulling cable out of the lever body storage tube if the standard rear cable splitters were in use (may be easier to insist on full outer and the external cable box, as used with disc brakes).

[MacB]

Well my thoughts so far are basically to replicate the existing shifter but as a thumbie. The first hurdle to overcome is the diameter of the barrel required to wrap the cable, I have had a thought though and I give you the Rohloff 'Ninja Star' shifter  :-

total cable pull/pull required is 96.2mm, 13 steps of 7.4mm

this would require a minimum diameter, assuming full 360 deg, of 30.7mm

scale that up a bit to allow for cable entry/exit so a 35mm diameter gives you 110mm of circumference, or your 96.2 + 13.8mm spare.

shifter body is a hockey puck style disc, about 40mm diameter, 14mm deep with an inner cable wrap disc, 10mm deep, with upper and lower cable channels and recess for cable nipple. The casing is in two halves and the inner cable wrap disc is clamped between them, there is an upper and lower cable entry/exit point aligned with each cable channel. So hockey puck with two jet nozzles poking out of the side. The inner disc/casing interface would deal with the 13 shift steps in the same way as a DT or barend shifter does. This would require approx 313 degrees of rotation for the full 96.2mm in either direction.

now here's the good bit, rather than a single lever you have a 3 or 4 spoke style lever, which slots into a splined interface in the disc centre, and bolts through to the shifter mounting bracket holding it all together. The diameter of the levers could be 60mm meaning they overhang the disc by 10mm all the way round. Or they could be longer, fatter, it could basically be an aftermarket option style thing. Choose the type of shifting 'Ninja Star' to suit your hands/thumbs. They could be orientated via the number of splines in the interface. You could even have a second shifting 'star' underneath, again optional, making it a true thumb and forefinger experience. Rather than having to move a single lever round 313 degrees you'd never need to move a lever more than 80 degrees with a 4 arm approach. If you went with an upper and lower 4 arm design the two Ninja Stars could be offset against each other to ensure a lever is always in easy reach.

this could also be mounted at a barend, using just one shifting star arm and that could be orientated in or out for preference.

the shifter mount has a hinged bracket and is 31.8mm with shims all the way down to 22.2mm. It should also be a cradle effect so the hockey puck disc could attach at 2 or 3 points providing stability and resisting twisting strain. Though this could impede the upper and lower arm combination idea.

Come on...what's not to like, offer an array of fancy anodised colours, two tone with one colour for the body and another for the star. Laser etch something like 'Ninja Death Star' onto it and flog it to MTBers worlwide 

[LEE]

The Rohloff Hub is crying out for an electric shifter, operated by a button on the handlebars.

As it is I'm looking at this..

New Rohloff shifter

[MacB]

The Rohloff Hub is crying out for an electric shifter, operated by a button on the handlebars.

As it is I'm looking at this..

New Rohloff shifter

Feck me, how rude are some people, I offer you a super cool, desinged on the back of a fag packet, Ninja Star concept and you paste up a link to some highly polished and professionally engineered bit of kit. 

[interzen]

Wake me up when someone (re)does a RapidFire shifter for the Rohloff (it was done a while ago, but never made it out of the prototype stage) - something modelled on the Alfine-11 shifter would be just the job, I reckon. Bar-end shifters would be better yet, but that probably comes under the category of 'insane optimism'.

Leaving price considerations to one side, the reason my Surly sports an Alfine-11 rather than a Rohloff is purely down to the fact that the Alfine-11 does *not* utilise a twist shifter. Maybe it's just me, but I just don't like them.

Since canned gears seem to be enjoying something of a renaissance at the moment, I wonder if Versa have anything up their proverbial sleeves ...

[Wowbagger]

What is a rapidfire shifter?

[Kim]

MTB trigger shifter.  Index finger goes one way, thumb the other.

[Biggsy]

What is a rapidfire shifter?

A Shimano indexed pod with a lever to push to pull cable, and a lever to release cable.

[interzen]

What is a rapidfire shifter?

One of these - this is the Alfine-11 shifter; the other trigger can't be seen because the brake reservoir is in the way:


Alfine 11-speed shifter by interzen, on Flickr

The 11-speed one works rather well, so it wouldn't be a stretch to make a 14-speed one - any more than 14 'steps' might prove to be trickier, although that's a bridge that'll get crossed when we come to it.

[Cudzoziemiec]

Wake me up when someone (re)does a RapidFire shifter for the Rohloff (it was done a while ago, but never made it out of the prototype stage) - something modelled on the Alfine-11 shifter would be just the job, I reckon. Bar-end shifters would be better yet, but that probably comes under the category of 'insane optimism'.

Leaving price considerations to one side, the reason my Surly sports an Alfine-11 rather than a Rohloff is purely down to the fact that the Alfine-11 does *not* utilise a twist shifter. Maybe it's just me, but I just don't like them.

Since canned gears seem to be enjoying something of a renaissance at the moment, I wonder if Versa have anything up their proverbial sleeves ...

Gripshift was my first experience of anything other than downtube friction shifting. I thought it was great until, about 9 years later, I found Rapidfire. In fact I still like the Gripshift, and for the front shifter it has the advantage over Rapidfire that you can trim the mech position by making small movements of the shifter; but trigger shifters do seem to be faster and more 'positive'.

[mrcharly-YHT]

Rapidfire shifters don't work when they get filled with water and then the water freezes.

Neither do STI levers.

I believe that a Rohloff twist shifter will still work, as it doesn't depend on return springs.

[Greenbank]

I believe that a Rohloff twist shifter will still work, as it doesn't depend on return springs.

A rapidfire style shifter designed for Rohloff wouldn't need return springs because hub gears require cable pull (there are two cables) when changing up or down. Mechs are sprung and only require a pull to go onto a larger sprocket, to go down the changer just puts enough slack in the cable; the return spring is there just to create the right amount of slack when changing down.

[mrcharly-YHT]

So what returns the rapidfire levers to their position?

[MacB]

You could do a trigger shifter but it would need to work with the existing hub and mechanisms. Same concept as my Ninja Star but with more traditional upper and lower triggers on a spring back to position basis. Slight limitations but it would work:-

you still need two cables and a barrel/disc able to accomodate the full 96.2mm for each.

each lever would work via pull only so the action of pulling one would need to open the other cable for release

you'd lose the ability to twist through a big range in one go, but I'm sure the triggers could be set to accomodate 1/2/3 shifts depending on distance pushed/pulled. Also don't see why they couldn't be able to do the full range in successive actions while reducing power to pedals or, as per tradition with hub gears, while standing still.

To be honest if you take my basic hockey puck design as being a universal then the centre of the disc can be mainly empty, the same as it is on the current twist shifter. What you then drop into that centre, to interface with the outer ring, could conceivably be interchangeable. Multi arm interface as per my original idea or ratchet/release type as per more traditional trigger style.

[Greenbank]

So what returns the rapidfire levers to their position?

D'oh, I see what you mean.

[MacB]

So what returns the rapidfire levers to their position?

There would need to be a return spring for each lever in the shifter itself, same sort of way as the SRAM TT barend shifters return to position each time.

[LEE]

I hate "Grip-shift" for derailleur with a passion but it's a much nicer feel on the Rohloff, you aren't fighting against spring-tension.

My Thorn Raven, with Drop-bars, has the shifter mounted on the steerer tube.  Because it's set up as a lazy tourer I tend to ride it with my hands on the tops which means the shifter falls easily to hand (better in fact that STI, bar-ends or down-tube shifters).

If you were looking for speedy changes whilst on the hoods, or in the drops, like you can get with STI, then there is no solution.

It's a good solution for relaxed touring where you aren't trying to keep your heart-rate within tight limits all the time.

Interested to see the "Fag-Packet design" though. 

Rapid-Fire (thumb/finger shifters) is much better than Grip-shift if you are trying to control a Mountain Bike whilst changing gear.