Author Topic: Drop 'bars & Rohloff: A dozen differ'nt ways  (Read 96701 times)

JimK

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Re: Drop 'bars & Rohloff: A dozen differ'nt ways
« Reply #60 on: July 24, 2012, 02:30:10 am »
I as the control turns, one cable must be under slightly more tension, therefore the other has less,

I think that when the shifter is not active, neither cable has any tension, or only very slight. When one rotates the shifter, one cable picks up tension and the other cable has absolutely no tension at all. As the hub mechanism switches into a new gear, the tension in the pulling cable must suddenly decrease, but I don't think the movement is enough that the "pushing" cable actually picks up any tension.

Moving slowly from one gear to the next, there is quite a definite step, a rise and fall in torque on the shifter. But if one flips quickly across several gears, the mechanism seems to glide more freely across the intermediate steps.

I don't think I have seen any other Rohloff besides the one on my bike. They're not too common around these parts!

Danneaux

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Re: Drop 'bars & Rohloff: A dozen differ'nt ways
« Reply #61 on: July 24, 2012, 02:36:21 am »
Quote
I think that when the shifter is not active, neither cable has any tension, or only very slight. When one rotates the shifter, one cable picks up tension and the other cable has absolutely no tension at all. As the hub mechanism switches into a new gear, the tension in the pulling cable must suddenly decrease, but I don't think the movement is enough that the "pushing" cable actually picks up any tension.
Thanks, Jim! Your explanation -- along with Andre's -- helps me get a much better grasp. Years ago, when Brandon Ives worked for Bike Friday, I saw a Rohloff with a broken flange at their facility (the result of early problems adapting the hub to such a small rim and really acute lateral spoke angles). Haven't seen one since that I could look at closely, though I did follow an early one on the bike path about two months ago. It has the yellow-and-blue sticker on it. The rider turned off before I could ask about it.

Once mine arrives, all (or much more) will be illuminated. Currently working with Andy and Robin on the best spec and size for my needs. Their feedback and experience is very helpful in determining which direction to go.

All the best,

Dan.

il padrone

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Re: Drop 'bars & Rohloff: A dozen differ'nt ways
« Reply #62 on: July 24, 2012, 08:18:59 am »
So much would be answered with a simple test ride or even test-feel, but alas, no Rohloffs are within access by me. Your collective descriptions are the next-best thing.

Dan, the Rohloff rotary shift is possibly closest approximated by the old,old, old rotary channel selectors on 1960-70s TVs - a smooth movement against slight resistance, then it neatly falls into place. The cable play does not matter too much, just be sure not to have it too tight as you'll lose the 'feel' for the gear.

Danneaux

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Re: Drop 'bars & Rohloff: A dozen differ'nt ways
« Reply #63 on: July 24, 2012, 08:30:45 am »
Quote
...possibly closest approximated by the old,old, old rotary channel selectors on 1960-70s TVs
Perfect! Boy, Pete, you brought back some childhood memories there! I know the feel exactly!

Thanks!

Very good suggestion wrt cable tension. I wonder of some of the few complaints I have heard might in some way be related to incorrect or too-tight cable tension.... From your description, I can see the importance of leaving a little play.

Best,

Dan.

triaesthete

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Re: Drop 'bars & Rohloff: A dozen differ'nt ways
« Reply #64 on: July 24, 2012, 05:32:25 pm »
Dan
another way to get an idea of the feel is to turn the spindle of your Shmidt dyno hub by hand. You will feel the bumps just the same but with a bit more initial resistance. They do smooth out with speed as you go across several like Jim says.
The oldest telly I can remember had huge channel selector buttons that you pushed in about 20mm with a big clunk as the one for the last channel selected popped back out. There were only four and one of them was unused! Perhaps we should TV carbon date  all the forum members?
Ian

swc7916

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Re: Drop 'bars & Rohloff: A dozen differ'nt ways
« Reply #65 on: July 24, 2012, 06:59:34 pm »
the Rohloff rotary shift is possibly closest approximated by the old,old, old rotary channel selectors on 1960-70s TVs - a smooth movement against slight resistance, then it neatly falls into place. The cable play does not matter too much, just be sure not to have it too tight as you'll lose the 'feel' for the gear.

This is a pretty close description.  The only thing I'd add is that while the cable play does not matter much, you do have to learn to feel where the resistance starts and then carefully turn it or you may find yourself overshifting.  Because of the long cables on my tandem I may have more slack than a single bike and I may be experiencing more stretch.  The resistance increases as the pedal force increases and this is when I tend to overshift, since I apply more force to the shifter.

Another issue regarding Rohloff hubs - that is not related to drop bar Rohloff shifter location - is tire changing for those who have the shift box.  When you disconnect the shift box from the hub, the shifter is free to turn.  If you turn the shifter and then re-attach it to the hub you will find that you don't have 14 gears anymore and the ones you have do not correspond to the correct numbers on the shifter.  To avoid this, I always rotate the shifter all the way to either gear 1 or 14 before removing the shft box and then make sure that the shifter is rotated all the way when I re-attach it.  I also carry a wrench to shift the hub in case I get things mis-aligned.

Danneaux

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Re: Drop 'bars & Rohloff: A dozen differ'nt ways
« Reply #66 on: July 24, 2012, 07:42:55 pm »
Quote
Perhaps we should TV carbon date  all the forum members?
I'm torn between voting "Yes!" and screaming "Noooooooooooo!" on this one. :D I do remember when *I* was the Remote Control and it was hard to be a couch potato unless you really, really liked just one channel (our TV received *two* channels over-the-air; we didn't have cable and sat dishes hadn't been invented). "Mute" was putting your fingers in your ears, unless you -- again -- got up and did something about it. Color hadn't been invented, so the world was black-and-white. I have the photographs to prove it.
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Truly, I can't begin to tell you how much these Rohloff "feel" descriptions help. I'm sure once I get mine, all will be clear, but these are things I've always wondered about from afar, and I am sure it is the same for others in the same boat. About all I had to compare it to (and that only by visuals) was a Grip-Shift. I now see the Rohloff shifter is an entirely different animal in feel as well as function.

Any comparisons between the Rohloff models (old, triangular grip with dark numbers vs. new, round, and white-numbered) and the Berthoud alternative?

swc7916, I can surely relate to your comments about the tandem's long cables (I own a derailleur tandem). The very length does alter feel to a degree, as does whatever friction is added by the lengthy cable runs. Excellent tips wrt indexing the shifter before tire changes and carrying an 8mm wrench; thanks!

Oh! Directly on-topic! I live on a feeder street to the local riverfront, off-street bike paths, so I see lots of bikes go by. I was putting a letter in the post box across the street a few moments ago when a tandem steamed by, ridden solely by the captain. It was a Rohloff bike, and the shifter was mounted somehow to the side of the top tube, just behind the headset. He was past-and-gone before I could give a shout, but he may ride by again. I suspected it might be a locally-built Co-Motion, but I didn't see the usual logos.

Best,

Dan.


il padrone

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Re: Drop 'bars & Rohloff: A dozen differ'nt ways
« Reply #67 on: July 25, 2012, 08:25:59 am »
About all I had to compare it to (and that only by visuals) was a Grip-Shift. I now see the Rohloff shifter is an entirely different animal in feel as well as function.

Any comparisons between the Rohloff models (old, triangular grip with dark numbers vs. new, round, and white-numbered) and the Berthoud alternative?

The thing to realise when talking about shifters is that the Rohloff shifter is really just a rotating dial operating two cables. In contrast to every other shifter its function and sensitivity is determined mainly by the gear hub itself (where the indexing occurs) together with the smoothness and tension of the cables. So when comparing a Rohloff triangular shifter and a Berthoud there should really be no difference apart from the feel of rubber grip compared to alloy.

Danneaux

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Re: Drop 'bars & Rohloff: A dozen differ'nt ways
« Reply #68 on: July 25, 2012, 06:18:15 pm »
Quote
the Rohloff shifter is really just a rotating dial operating two cables... [so] there should really be no difference apart from the feel of rubber grip compared to alloy.
<nods> Yes, Pete, I see. This thing gains in beauty the more I learn of it.

Still, I find myself wondering if there are differences in the grip construction that might result in a different tactile "feel" when switching from one to another. For example, if anyone had an earlier triangular-grip Rohloff shifter...did the subsequent round version feel any different? In other words, did Rohloff take the opportunity to improve the internals to reduce friction, or something? Or were the changes mostly cosmetic, like the change in shape and added white indicator numbers? And does the alu Berthoud shifter have any added mass that might alter the feel?

I guess what is in the back of my mind is how the shape and -- more importantly -- the mass, of a gear-shift knob can change the feel of a car's manual transmission when shifting. Assuming the same linkage, it is possible to go far in tuning the "user interface" by going from, say, an OEM molded plastic knob to one of machined aluminum. For those who have gone from one sort of Rohloff shifter to another, did you notice any difference?

I.can't.wait. to get my hands on one of these things and take some measurements.

Thanks!

Best,

Dan. (who is getting...Ideas...!)

swc7916

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Re: Drop 'bars & Rohloff: A dozen differ'nt ways
« Reply #69 on: July 25, 2012, 07:39:50 pm »
I find myself wondering if there are differences in the grip construction that might result in a different tactile "feel" when switching from one to another.

I only have experience with the shifter on my bicycle - which I believe is the "triangular" shifter - but other than differences in the diameter of the shifter or texture/material of the gripping surface, I can't imagine there'd be any differences.  Mine rotates pretty freely when the shift box is disconnected.  As far as feel is concerned, it must be understood that the shift occurs remotely; that is, the indexing is in the hub, not the shifter.  With an indexing derailluer system, the shift cable is under spring tension and you're either pulling against the tension or releasing the tension to shift and the feel is different between upshifting and downshifting (at least, that's been my experience.)  When shifting one way, you can feel that you are pulling the derailleur whereas in the other direction you can feel the spring tension snapping the derailleur in to the next position.  With the Rohloff there is no spring tension to overcome or release and because of this the shift cable is always slack, albeit only a little.  When there is no pedalling going on, the shifting is the same up or down.  When pedalling, the downshifts seem to be harder but I think that's due to the fact that you're shifting down because of increasing load.

swc7916

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Re: Drop 'bars & Rohloff: A dozen differ'nt ways
« Reply #70 on: July 28, 2012, 02:06:43 am »
I just saw this...CoMotion's new drop-bar Rohloff shifter:

« Last Edit: July 28, 2012, 02:11:36 am by swc7916 »

il padrone

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Re: Drop 'bars & Rohloff: A dozen differ'nt ways
« Reply #71 on: July 28, 2012, 02:17:09 am »
Ah, now that is even better :).

'Top of the drops' shifter, but with a completely enclosed cable drum (in contrast to Gilles Berthoud's open cabling), so preventing the problems of water/grit building in your housing to cause corrosion or jamming. Used with the EX box this would keep your cable run completely sealed from such problems.
« Last Edit: July 28, 2012, 03:24:38 am by il padrone »

il padrone

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Re: Drop 'bars & Rohloff: A dozen differ'nt ways
« Reply #72 on: July 28, 2012, 02:29:33 am »
Still, I find myself wondering if there are differences in the grip construction that might result in a different tactile "feel" when switching from one to another. For example, if anyone had an earlier triangular-grip Rohloff shifter...did the subsequent round version feel any different? In other words, did Rohloff take the opportunity to improve the internals to reduce friction, or something?

The internals of the shifter, new or old, is simply a cable drum. There is no real mechanism to it and either drum is free running.

Rohloff changed the new shifter to make the cable insertion process simpler. They also made the gear numbers white to stand out and printed off the grip area, rather than raised on the grip rubber (which eventually will wear off). The numbers are rather superficial, as you will soon find out after riding with the Rohloff for a year or so. You simply shift one way for higher gear and the other for lower. I managed to goof up my GLW's cables and have them reversed. For her the top gear is 1 and 14 is lowest - no great grief, I will fix it when I next have to replace the cables (20,000kms or so). The actual gear is really of little consequence as you are not double shifting onto different gear ranges - the hub does all that for you.

The new grip is round and for many people feels more comfy to grip while riding. OTOH, the triangular grip is easier to flip between gears, I find. My wife was having trouble doing shifts wearing her nice winter wool gloves - they slipped on the shifter. The triangular shifter would give her a face to push on. Her wool gloves have had to be banished from winter riding use.
« Last Edit: July 28, 2012, 02:34:38 am by il padrone »

Danneaux

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Re: Drop 'bars & Rohloff: A dozen differ'nt ways
« Reply #73 on: July 28, 2012, 03:13:35 am »
Quote
I just saw this...CoMotion's new drop-bar Rohloff shifter
Oh! Nicely found, swc!

This being early Friday evening here in the PNW (Pacific Northwest), I'll try and drop by Co-Motion on Monday and see if I can find out more from Dwan or Dan and see what they have to say. They're located just 6mi/9.6km from my front door. Bike Friday is about the same distance the other direction, and they've been doing Rohloff'y stuff as well.

Best,

Dan.
« Last Edit: July 31, 2012, 12:57:31 am by Danneaux »

JimK

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Re: Drop 'bars & Rohloff: A dozen differ'nt ways
« Reply #74 on: July 28, 2012, 03:20:15 am »
Ask those co-motion fellows if they ever visited their cousin Robbie in Cuyahoga Falls back in like third grade. Robbie was my neighbor in those days. I think maybe we all went out bike riding together then. Small world, eh?!