Bicycle Mechanics - paddle shifter for internal 3 speed

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jpwillia
08-12-09, 04:11 PM
I am thinking of putting a SRAM i-Motion 3spd disc-ready (http://www.ebikestop.com/sram_i_motion_3spd_disc_ready_36h_hub_130mm_oln_19t_cog-HU2531.php) hub on my next bike. but i hate grip-shifts. i know shimano makes the tapfire 8 speed shifter for nexus internal hubs. is there something i can use for the sram? im open to sneaky work arounds if they will work. i know some peopl have used three stage handlebar mounted fork lockouts for stermy archer hubs before with some success. also, in general, how much of a beating could such a hub cost.

tatfiend
08-12-09, 05:14 PM
Per my understanding the iM3 hub has a different amount of shift cable pull than any other 3 speed hub including the old Sram T3 or Sachs Torpedo hub. Not aware of any shifter option other than the hub specific Sram twist grip. You might contact Jtek and let them know that you are interested in a version of their bar end shifter for the iM3. They now list it for the Shimano 7 and 8 speed hubs as well as for the Sturmey Archer 8 speed.
jpwillia
08-12-09, 10:21 PM
i think paddle was the wrong term. i meant trigger. does anyone make that either?

tatfiend
08-12-09, 11:22 PM
Not that I am aware of. The SRAM web site did not show anything the last time I checked it. The only shifter shown is the twist shifter. I do have a trigger shifter for the older Sachs Torpedo hub but have no idea if it will work. I have read that it is not compatible with the iM3.
kamtsa
08-12-09, 11:38 PM
SRAM sells a trigger shifer for DualDrive

http://www.bikeparts.com/productinfo/SRAM-DualDrive-3spd-left-trigger-shifter-72548-20614.html

The cable moves about half the length per click than a standard 3x front derailleur shifter. It may or may not match the requirements of the iMotion. I don't know.

Edit: you may want to get an IM3 twist shifter, measure the cable travel per click and go from there. You can use for example a travel agent in reverse to reduce the cable movement of a standard shifter.

Kam
tcs
08-13-09, 06:16 AM
Yeah, the iM3 is sweet. It'll ruin you for any other three speed hub, that's f'sure.

Anyway, it's still a three speed. Low gear is cable slack. High gear is cable taught. 2nd gear is half way in between. If you really can't stand the grip shift, get yourself a 9- or 10-gear indexed shifter you do like. Set it up so you can pull the iM3 into high gear in one of the top positions, and then note what index position you're in when the cable goes barely slack and you're in low gear. 2nd will be the index position half way in between.

tcs