Poor shifting on new Rohloff on tandem

[Andre Jute]

I don't have quick releases anywhere on my bike as part of the systems approach to security, and because no flats are expected with the banded tyres I use. But my Rohloff isn't the TS either, it is the CC quick release version, but bolted on. That's an interesting point Stu makes. Unless you're pretty experienced (which I guess Chris is, not only a professional mechanic but head mechanic at a bike shop), you should use a torque wrench for tightening the bolt (and be very careful if you use a QR). The rating is only 6 Newton meters, easily exceeded even with a short-handled torque wrench.  I'm sure Herr Rohloff wouldn't have specified it that low if it didn't matter. The SON dynamo hub, also familiar to many Rohloff owners, is specified for higher fastening torque, and so is the Shimano Nexus internal gear hub (I have no experience of the Alfine but imagine it as a beefed up Nexus, so probably unlikely to have lower fastening spec).

Oddly, I now can't remember whether I lift off when I change gear on the Rohloff, but then I'm not a scientific rider, just a recreational putterer. I certainly never lift off to the stage where it degrades my forward motion to the point of an irritation that I remember. But I do remember writing on this board that on an agricultural gearbox, which is how I described the Rohloff after the silky smooth Nexus boxes I loved, the gear change was tha crudest part, it was so rough and irritating. It probably hasn't become all that much smoother in 5000km, though some, but I became used to it, and the other benefits of the box (clean hands!) started to assume greater importance in my mind. It is, as has been suggested, a smart idea to give the Rohloff considerable time to rub in with you. Almost nobody but the trendies and the fashion victims like the Rohloff from the word go, but it is rare to find anyone with a few thousand clicks on a Rohloff who'll even consider going back to derailleurs.

On the other hand, it sounds like you're a pretty successful tandem pair on the derailleurs and so expert on them that, for you, it wouldn't be a hardship to return to them.

Andre Jute

[benstevens]

We have a Rohloff on our tandem and like you have the cranks 90 degrees out of phase for the reasons that you mention.  I do find that we have to be quite careful shifting from gears 7-8, but find the best way is for me (pilot) to try to stop the pedals moving for an instance when they are flat (helps having SPDs, stoker at pedal up/down position).  We have never had anything as bad as you describe in all the other gears, just the occasional refusal to change when I forget to ease off going uphill. 

We've found that the Rohloff is more forgiving than derailleurs, it simply will not change if it doesn't want to, where as a derailleur would skip and normally end up with the chain coming off or crunching gears at the very least.

[ewenG]

Hi Chris, are you running full-length Rohloff cable housing?

You say the shifting "shifts fine when on the repair stand, and reasonably well when riding the bike solo". Can you compare the shifting performance and feel to a normal, i.e. non-tandem shifter?

Thanks,
Ewen.

[il padrone]

The only time I have a problem shifting is on the 7-8 / 8-7 shift and under load.    

Funny thing - I only have any rough shifts going from 8-7. The shift up from 7-8 is as smooth as all of the other gear shifts with the Rohloff, no need to back off power at all.

[Relayer]

Funny thing - I only have any rough shifts going from 8-7. The shift up from 7-8 is as smooth as all of the other gear shifts with the Rohloff, no need to back off power at all.

Same here.

[Danneaux]

Dan I have slightly modified this post to fit in with the split in topics

Hi All,

SWC, running a tandem with Rohloff is less common among Forum members than single bikes with Rohloffs. You probably have more experience doing so than the rest of us, and you've mentioned you ride that bike more often than the derailleur tandem you also own.

Efficiency comparisons aside, you mentioned your Rohloff shifts are "quick and positive", unlike the OP's experience. Lets see if we can find something in that which could prove helpful to the OP...

Crank-phasing proved problematic for him in shifting.
Can you tell us if your tandem's cranks are in-phase, or out-of-phase? If the latter, by how much?

He found it difficult to shift under the continuous load placed on the drivetrain by having the cranks out-of-phase (which he preferred). Can you tell us a bit more about your shifting technique (i.e. shifting under load vs backing off a bit while making the gear change) that has proven successful for you?

Can you tell us if you are using a Rohloff with q/r, or with nutted axle? Axle tension may have been a factor for the OP as well.

Whatever, your Rohloff is working well for you, unlike the OP. Perhaps there is something in your experience that can help him achieve his goal of getting a tandem with Rohloff drivetrain to work for his needs. Though the Rohloff has proven less efficient for you, you still prefer it over the derailleur model for reasons already stated.


Debates concerning Rohloff vs. Derailleur efficiency would better take place in the thread already devoted to that topic, here: http://www.thorncycles.co.uk/forums/index.php?topic=4073.0
Debate on  Rohloff vs. Derailleur efficiency in Tandems has been moved into Rohloff Efficiency on a tandem - Stutho

Best,

Dan. (wearing his moderator helmet)

[swc7916]

Thank you Dan.

Our tandem cranksets are in-phase and our Rohloff has a quick release axle.  I included a link to photos of the bike in my first post which show how it is set up.

There are a couple of factors with tandems as opposed to single bikes that make shifting a Roholff more difficult: One is that with the increased weight and power applied, tandems put more load on the hub.  The second is that it's difficult to get two people to back off at the same time during the shift.  Don't get me wrong, not all shifts are quick and positive; only good ones, which is most the time.  As I stated before, shifting is more difficult as the load increases, so I try to maintain a relatively high cadence and light-to-moderate pedal pressure.  Shifting at the right time is a matter of experience and I don't always get it right.  Usually what happens when I get it wrong is that it will require more force and I will over-shift, going two gears instead of one.  If I wait until the load is high it can take a lot of force to make it shift.  Perhaps part of the reason that we experience slower overall speeds on the Rohloff tandem is that I practice more "pre-emptive" shifting; that is - as we approach inclines I tend to shift early to avoid being stuck in a situation where I can't make it shift.

[Andre Jute]

   Andre  I have slightly modified your post due to the split of topic - stutho

The important thing about a newish Rohloff is that the change is miserable. Though I admired the concept of the Rohloff, and had extensive familiarity with hub gearboxes, when I first acquired a Rohloff (in an admirable installation by the manufacturer who was the first to adopt Rohloff as an OEM box), I brassed off some people here by describing it as "agricultural". It was some thousands of klicks before the box smoothed out enough to be forgotten, and I don't think it will ever change with the jewel-like precision of Shimano's Nexus. Despite this, I am as convinced as any of the other aficionados here that I spent my money wisely when I bought a Rohloff. Though I have zero tandem experience, it seems pretty obvious to me that the length of cabling on a tandem will aggravate the baulking of a new Rohloff box. It's just one of those things that you have to live through, like a new Brooks saddle not being as comfortable as you hoped for a thousand miles or more. (Buy a B73, the triple coil spring one, they're comfortable  straight out of the box.) I think you're probably still a 1000km away, SWC, from having a Rohloff box smooth enough not to notice its changes. Then one day you wonder what the fuss was about.

Chris's problem is at an altogether different level.

Andre Jute

[swc7916]

I would never have characterized the Rohloff as agricultural, although it is a relief to hear someone say that switching to a Rohloff is not all sunshine and fairy dust.  The shifting has never been balky, but because of the necessity of play in the cable I find that I can't just grab the shifter and turn it.  I usually have to turn the shifter until I feel tension in the cable and then shift.  With the derailleur tandem we could build up speed prior to a hill and using our momentum pedal until we could hardly turn the cranks anymore before shifting.  The Rohloff won't shift under those conditions, requiring me to shift earlier thus losing momentum on the climb. The noise that many people find objectionable has never bothered me.  I've read some people describe it as a "grinding" sound whereas I would call it a "whirring" sound, not unlike the old bottle generator I had on my bike as kid.  Besides, on the tandem it's so far behind me I hardly hear it anyway.  As far as break-in is concerned, I would think that due to the higher loads that a Rohloff would encounter in tandem service it would break in fast than a single bike.  1000Km is only, what, 620 miles? I suspect that it will take another couple of thousand mile before it's completely smooth.  (I'm an American, I don't speak metric.  

[fleur]

I have the impression that Rohloff changed something in their manufacturing so that hubs produced in the last years make less noise and have better (but not perfect) gear shifting when new than the hubs produced during the first years of production.

The shifting indeed requires more and more power when more power is applied on the pedals. We have a special tandem with a freewheel and not unity ratio of the stoker-captain transmission equiped with Rohloff, so the phase changes.  When cranks are not in phase, it is more difficult to shift unless the shift occurs when the stoker is at the dead point and the captain interrupt his load on the pedal (which is possible since the captain is at the rear and sees the stoker pedaling).  Having the crankset with a fixed 90 degre phase difference is I think a kind of worst case.

I think also that the Rohloff experience will depend of the type of tandem and usage.  A sport oriented tandem and usage will probably give a worse experience of the Rohloff gear shifting than a touring/travel tandem.

[stutho]

This topic has been split into Two. Please also see Rohloff Efficiency on a tandem

I have tried to maintain the integrity of each.

Best regards

Stuart