Author Topic: Rohloff Efficiency on a tandem  (Read 3173 times)

swc7916

  • Jr. Member
  • **
  • Posts: 52
Rohloff Efficiency on a tandem
« Reply #15 on: June 22, 2012, 03:28:41 PM »
I'm afraid this is all smoke and myth. I refer you back to that efficiency comparison graph. It shows the net outcome of the whole wheel in operation ie. includes all losses from gear rotation and any seal friction.

If your speeds with the Rohloff tandem are lower I'd suggest you have a look at a few other factors. Brakes rubbing? Gear ratio and range the same or different? Position on the bike? I don't know what it is, but there is no way a Rohloff hub should give you a 10% lower speed - that's a huge cutback.

You're the second person to call me a liar.

I don't give a damn what the comparison chart says, my experience with two otherwise nearly identical bikes is that the Rohloff is up 10% slower.  If you would read my previous post you would see that I have accounted for all the things that you think I'm too stupid to check.




wheezy

  • Full Member
  • ***
  • Posts: 129
Rohloff Efficiency on a tandem
« Reply #16 on: June 22, 2012, 04:00:36 PM »
Don't be so touchy. No-one's called you anything of the sort. They're merely taking an opposing view. It's called debate.
« Last Edit: June 22, 2012, 04:11:38 PM by wheezy »

wheezy

  • Full Member
  • ***
  • Posts: 129
Rohloff Efficiency on a tandem
« Reply #17 on: June 22, 2012, 04:07:58 PM »
I wonder what the (generally regarded) small efficiency loss, in comparison to clean, well-adjusted derailleurs actually amounts to in real life?

A mile an hour over ten miles, or something like that? (assuming some kind of anomaly above).
« Last Edit: June 22, 2012, 04:10:10 PM by wheezy »

swc7916

  • Jr. Member
  • **
  • Posts: 52
Rohloff Efficiency on a tandem
« Reply #18 on: June 22, 2012, 04:18:34 PM »
Don't be so touchy. No-one's called you nothing of the sort. They're merely taking an opposing viewpoint. It's called debate.

Writing "none of this is true" and "this is all smoke and myth" is debate?  I'm sorry, but they're questioning my intelligence and integrity.  I'm experiencing a speed difference between the two and these people are telling me that I am wrong; it can't be the Rohloff.  The second responder didn't even seem to have read my previous post.

stutho

  • Administrator
  • Hero Member
  • *****
  • Posts: 850
Re: Rohloff Efficiency on a tandem
« Reply #19 on: June 23, 2012, 07:34:26 PM »
SWC,

I very much value your opinion on this and I certainly do not believe you are lying. 

Most of us on the forum do not have a Rohloff equipped tandem. I suspect that this is why your experiences differ to others on the forum. Although I can not reason why a tandem should make a difference. 

My own (non tandem) experiences were that overall, changing to a Rohloff, made very little difference in terms of objective measurements of speed. BUT subjectively the Rohloff has always felt slower - others have noted the same thing.  Why I can not say  maybe there is slightly less feedback through the Rohloff hub to the balls of the feet?!

Best Regards

Stutho       

sg37409

  • Full Member
  • ***
  • Posts: 167
Re: Rohloff Efficiency on a tandem
« Reply #20 on: June 23, 2012, 07:41:19 PM »
this thread is pretty interesting.
I would tend to agree with the notion that the rohloff is "draggy" and am not surprised that the top speeds are lower. I am a bit surprised they are so much lower.
Rohloffs are heavier, and are much harder work when riding in a club setting where wee accelerations are required often.

I ride a rohloff tandem (slowly) with my kids. Changing is dead easy for me, but we dont have fancy stoker freewheels to complicate things. My "power" output (such as it is) is much greater than my kids so if I ease off to change, then we ease off. Easing off to change is pretty important.

My rohloff solo is the bike I ride most, I enjoy it much more than my other bikes, but its a lot heavier and a bit slower. I think it feels slower than it is for many reasons.

Bringing back to topic, No reason I can think of to say why a rohloff is less efficient on a tandem than a solo.
Gear changing is a different matter: Longer cable runs, and co-ordinating easing off makes shifting harder, but then again derailler shifting on a tandem (front esp.) is harder than solo equivalent.