nomad build

[mickeg]

I'm now toying with the idea of converting the Sherpa to a rohloff. I have a radical designs cyclone IV trailer which I use for extended touring. So I rarely have more than 15 KGs on the rear rack any other time. Plus I can always go on a diet. I also like the idea of having a frame that I can go back to derailleurs with if I have rohloff issues

I'm looking at getting SIS to build a wheel with the following rohloff:

https://www.sjscycles.co.uk/hubs-internal-hub-gear-brake/retrofit-rohloff-speedhub-50014-cc-14-speed-gear-hub-32-hole-with-disc-fitting-8021-red/

Can anyone tell me what the torque arm is used for? As far as I can tell it's used it you need to change the default direction of the ex mech.

When you pedal, if you are in gear 11, that is direct drive.  Then it is just like a single speed.  But in all other gears, the way that the internally geared hubs work is that they apply a torque to  the frame.  The torque arm is used to brace the hub against the frame.  The old three speeds or other internally geared hubs that had a very small range did not need much of a device to brace the frame for hub torque, they usually could do it with an axle that was flattened.  But the Rohloff with the huge range can apply a lot of torque to the frame.  It needs a better bracing method.

Be careful when you order  a hub.  There are lots of options:
  quick release or nutted axle
  color
  spokes, 32 or 36
  shifting mechanism EX box or internal gear cables
  disc brake or not
  method of bracing the hub against the frame for torque.

You might want to talk to someone at SJS about your plans to make sure that the hub you order is teh right one for the bike.

Also, the Raven or Nomad have an eccentric bottom bracket for chain adjustments, the Sherpa would have no such adjustment.  Thus, you would need the chain tensioner.

I do not recall if you are looking at drop bars or flat bars.  The Rohloff was originally designed with flat bars in mind, options for drop bars are varied.  After trying a few options I finally decided that the HubBub adapter for the Rohloff shifter works best for me.  But I have been using bar end shifters for decades so I was accustomed to reaching for a shifter on the end of the handlebar.
http://www.cyclingabout.com/rohloff-hubs-with-drop-handlebars/

[rualexander]

Read through my thread, it's all in there http://thorncyclesforum.co.uk/index.php?topic=3235.0

[martinf]

Torque arm is needed because the Sherpa frame doesn't have the long slotted Rohloff drop out.
Nomad, Mercury, Raven, etc. have this drop out, so there is a small peg on the version of the Rohloff hub used with these frames that does the job of the torque arm, but neater.

Not sure if you can fit a disc brake to a Sherpa frame, so check with SJS (unless you want the option of moving the hub to a disc-compatible frame later on).

I have a hub gear in a derailleur bike frame, I use the Surly Singleator tensioner, this has just one pulley so slightly easier to clean than the Rohoff tensioner. A tensioner doesn't look as neat as my Thorn bikes, and impossible to fit a Chainglider, but it works well enough.

[dick220369]

Nomad, Mercury, Raven, etc. have this drop out, so there is a small peg on the version of the Rohloff hub used with these frames that does the job of the torque arm, but neater.

So the Thorn rohloff equipped bikes use a custom rohloff? If I upgraded my Sherpa to a rohloff, I was hoping the option would be available to upgrade to a Nomad frame later on. But this sounds like I would have to be careful about the rohloff I buy otherwise I might find I have to use the torque arm on the Nomad as well.

[Paul S]

So the Thorn rohloff equipped bikes use a custom rohloff?

No. Nomad Raven & Mercury bikes use a frame made to accept an OEM hub without all of the extra complications.

[rualexander]

Nomad, Mercury, Raven, etc. have this drop out, so there is a small peg on the version of the Rohloff hub used with these frames that does the job of the torque arm, but neater.

So the Thorn rohloff equipped bikes use a custom rohloff? If I upgraded my Sherpa to a rohloff, I was hoping the option would be available to upgrade to a Nomad frame later on. But this sounds like I would have to be careful about the rohloff I buy otherwise I might find I have to use the torque arm on the Nomad as well.

All you would need to do is take off the torque arm and axle plate and replace with the OEM axle plate https://www.sjscycles.co.uk/hub-spares/rohloff-aftermarket-to-oem-axle-plate-converter-mki-for-qr-hub/

There seems to be a newer version as well that is twice the price https://www.sjscycles.co.uk/hub-spares/rohloff-aftermarket-to-oem-axle-plate-converter-mkii-for-qr-hub-8234/

[dick220369]

Been looking at the rohloff installation document and it all looks straight forwards.

@rualexander,

Do you have any pictures of the cable routing you used from the ex mech up the seatstay? The early pictures in you post about your conversion don't work for me.

[rualexander]

Been looking at the rohloff installation document and it all looks straight forwards.

@rualexander,

Do you have any pictures of the cable routing you used from the ex mech up the seatstay? The early pictures in you post about your conversion don't work for me.

Yes, the early photos in that thread got lost when the forum was updated a while back.
Here's a photo now though.
I believe it may also be possible to attach the torque arm to the seatstay rather than the chainstay which would clear up the space below the chainstay for cabling and the ex box. I'm sure I've seen it done somewhere on the internet.

[martinf]

I think one reason the torque arm attaches to the chainstay rather than the seatstay is that the former is generally much stronger.

I'd suggest asking the advice of SJS (they know about the construction of the Sherpa frame) before trying to attach it to the seatstay.

[dick220369]

Thanks for the photo rualexander.

I've just dropped SJS an email asking a few questions.

Looks like I will go down the Sherpa retrofit path with the plan of getting a Nomad frame at the end of the year

[Paul S]

Looks like I will go down the Sherpa retrofit path with the plan of getting a Nomad frame at the end of the year

It's not a rout I would chose, but if your desire is for a Nomad frame & the Hub.

Fare-play chap. 

[bobs]

I have to agree with  Paul , you would be better buying the Nomad frame at the start.  There would be additional cost ,torque arm and chain tensioner. It would be a botched job especially if you intend to buy a new frame eventually.

Bob

[jags]

yes kinda agree with the lads hold on until u can buy the nomad frame ,use the sherpa for winter take out the shiney new nomad when the sun shines .

anto.

[rualexander]

I have to agree with  Paul , you would be better buying the Nomad frame at the start.  There would be additional cost ,torque arm and chain tensioner. It would be a botched job especially if you intend to buy a new frame eventually.

Bob

Torque arm comes with the hub.
No need for a chain tensioner, just choose the chainring and sprocket combination carefully using a 'magic gear' calculator.

[Paul S]

No need for a chain tensioner, just choose the chainring and sprocket combination carefully using a 'magic gear' calculator.
[/quote]

Each to there own, but a retrofit to a bike without an eccentric and a chain tensioner is not a rout I would chose.