Nexus cable pull and shifter options.

Quoth David L. Johnson:

Quoted message said:

I just found a Shimano Nexus 7-speed hub at the Trexlertown swap meet. The shifter is not part of
the deal, though.

Standard shifter is either a twist-grip or a rapid-fire type. Is there any chance that an STI
shifter would pull the right amount of cable?

Nope.

Best setup for drop bars is to put the RapidFire shifter on the left, just below the brake lever.
You'll shift with your left thumb, and the cable routing will be neat and smooth. I used to have a
similar setup on my Peugeot "PX-7", see: sheldonbrown.orgpx7.htmlOpen ↗

See also: sheldonbrown.comshimano nexus.htmlOpen ↗

Sheldon "Neck's Us" Brown +------------------------------------------------------------+
| What are politicians going to tell people when the | Constitution is gone and we still have a
| drug problem? | -- William Simpson, A.C.L.U. |
+------------------------------------------------------------+ Harris Cyclery, West Newton,
Massachusetts Phone 617-244-9772 FAX 617-244-1041 harriscyclery.comharriscyclery.comOpen ↗ Hard-to-find parts
shipped Worldwide captainbike.comcaptainbike.comOpen ↗ sheldonbrown.comsheldonbrown.comOpen ↗

Sheldon Brown said:

Quoted message said:

I just found a Shimano Nexus 7-speed hub at the Trexlertown swap meet. The shifter is not part of
the deal, though.

Standard shifter is either a twist-grip or a rapid-fire type. Is there any chance that an STI
shifter would pull the right amount of cable?

Nope.

Best setup for drop bars is to put the RapidFire shifter on the left, just below the brake lever.
You'll shift with your left thumb, and the cable routing will be neat and smooth.

Nuts. is there a way it would work with a downtube lever, or friction shifting, or Command shifters,
or any of those options? Does it take the nexus-specific rapid-fire shifter?

--

David L. Johnson

__o | The trouble with the rat race is that even if you win you're _`\(,_ | still a rat. --Lilly
Tomlin (_)/ (_) |

David L. Johnson said:

Sheldon Brown said:

Quoted message said:

I just found a Shimano Nexus 7-speed hub at the Trexlertown swap meet. The shifter is not part of
the deal, though.

Standard shifter is either a twist-grip or a rapid-fire type. Is there any chance that an STI
shifter would pull the right amount of cable?

Nope.

Best setup for drop bars is to put the RapidFire shifter on the left, just below the brake lever.
You'll shift with your left thumb, and the cable routing will be neat and smooth.

Nuts. is there a way it would work with a downtube lever, or friction shifting, or Command
shifters, or any of those options? Does it take the nexus-specific rapid-fire shifter?

Nuts? Why? The RapidFire shifter is very nice, I sell them for $34.95 with cable and anchor bolt.

No other indexed shifter will work. Theoretically you could use some friction shifter, but there
would be a high probability of missed shifts, and a fair risk of damaging the hub.

Sheldon "RapidFire Is Good" Brown +-------------------------------------------------------+
| I found no fault with the cook, and it was the rule | of the voyage that the cook found no fault
| with me. | There was never a ship's crew so well agreed. | --Joshua Slocum _Sailing Alone Around
| The World_ | eldred.ne.mediaone.netsaaw.htmOpen ↗ |
+-------------------------------------------------------+ Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041 harriscyclery.comharriscyclery.comOpen ↗ Hard-to-find parts shipped Worldwide
captainbike.comcaptainbike.comOpen ↗ sheldonbrown.comsheldonbrown.comOpen ↗

Sheldon Brown said:

Nuts? Why? The RapidFire shifter is very nice, I sell them for $34.95 with cable and anchor bolt.

The only problem is that they are not really well-adapted to drop bars. I rode with a guy with a
Rohloff who had a separate bar, like tourists use to hold all the extra gadgets that don't fit on
the bar. He used it just for the shifter. From your description this won't be so bad, but an
STI/Ergo solution would be nicer.

I'll get my order in soon.

--

David L. Johnson

__o | We have a record of conquest, colonization and expansion _`\(,_ | unequalled by any people
in the Nineteenth Century. We are not (_)/ (_) | to be curbed now. --Henry Cabot Lodge, 1895

Quoted message said:

I just found a Shimano Nexus 7-speed hub at the
Trexlertown swap meet. The shifter is not part of the
deal, though.

Standard shifter is either a twist-grip or a rapid-fire
type. Is there any chance that an STI shifter would pull
the right amount of cable? > How much pull is needed per
shift, anyway?

--

David L. Johnson

I'm following up on an old thread, not to continue the
discussion but for the benefit of anyone googling for a
solution to the question of whether it's possible to adapt a
Shimano 9sp shifter to a Nexus 7sp internal gear hub. It is.

I measured the cable pull of the two systems and found that
the ratio of the Nexus/9sp systems was slightly greater
than 2:1 (Unfortunately, I've lost track of the
measurements so I can only describe them from memory in
general terms). I had a spare Travel Agent brake cable
adapter on hand and measured the circumference of the two
diameters and found that the ratio was slightly less that
2:1. Doing the math I found that running a SH 9sp shift
cable through a Travel Agent would come very close to a
producing a Nexus cable pull.

I've built a bike with this setup and it works very well. I
used a 9sp barend shifter with a travel agent and an inline
barrel adjuster. I was prepared to modify the Travel Agent
ratio with a layer of masking tape and/or filing, but found
it wasn't necessary. Here's a picture of the resulting bike:
fischer-wade.homelinux.orgbiciOpen ↗

You can find the Travel Agent here: excelsports.-excelsports.-Open ↗
com/new.asp?page=8&description=Travel+Agent+%2Dea%2E+with+a-
djuster&vendorCode=PS&major=6&minor=8

Cheers, Bret

Do any of the Shimano Nexus experts out there see any
problem with this? Would it harm the hub in any way?

I really like this idea and would love to give it a shot.

Thanks for sharing Bret.

-Bruce-