Twist Grip for Rapid Fire

[lemmy]

Following on from my post about narrowing my Tasman handlebars, the only way seems to be to swap the Shimano twist grip shifter for the Rapid Fire trigger type.

It's a long shot I know but has anyone done this? Or knows if it would present any particular problems?

I understand that since both are Shimano items and intended for the Alfine 8 speed hub, the indexing should be the same. It would be nice if it was a simple matter of undoing the cable from the twist shift and attaching it to the Rapid Fire. Except....life's not like that.

 

[oigoi]

I thought a rapid fire unit was for derailleur gears? not had an 8 speed hub so not sure what shifters they come with.

Would all depend if the rapid fire unit pulled or released the cable the same amount each time as the twist grip does. Perhaps if you measured that - how much the rapid fire unit moves the cable for each shift and how much the twist grip moves it - that would show an equivalency

 

[Blew it]

Following on from my post about narrowing my Tasman handlebars, the only way seems to be to swap the Shimano twist grip shifter for the Rapid Fire trigger type.

It's a long shot I know but has anyone done this? Or knows if it would present any particular problems?

I understand that since both are Shimano items and intended for the Alfine 8 speed hub, the indexing should be the same. It would be nice if it was a simple matter of undoing the cable from the twist shift and attaching it to the Rapid Fire. Except....life's not like that.

Rapidfire trigger shifters can be used with derailleur or hub gears, just make sure the number of indices on the shifter is the same as the number of gears to be shifted.

The Wisper 906 Alpino uses a rapidfire shifter with an eight speed alfine hub, as does my Kalkhoff Sahel. Raleigh machines use a gripshift to control the Alfine hub.

 

[lemmy]

The Wisper 906 Alpino uses a rapidfire shifter with an eight speed alfine hub, as does my Kalkhoff Sahel. Raleigh machines use a gripshift to control the Alfine hub.

My Kalkhoff Tasman uses a grip shift to control the Alfine hub and I'd hope to save some bar space with the rapid fire, so that I can carve a bit off the bars, thus narrowing them.

It sound all easy enough in principle. I just don't fancy changing the whole cable. If I can use the same cable, it would be ideal, the adjustment of the Alfine gears being no problem at all.

 

[Blew it]

The only cable you may have to replace is the inner. The reason being the clamping method on the hub cassette unit crucifies the inner cable. Both gripshift and triggershifters require the inner cable to be threaded in through the shifter first, almost impossible to do if the original inner cable is badly frayed. The inner gear cable needs to be of the long variety, 2100 mm in length. Providing it is not damaged, the outer cable can be re-used.

 

[Blew it]

Further to my last reply.

If changing from a revo shifter to a trigger shifter, there is no need to disturb the outer cable. For the reasons given previously, have a new 2100 mm long inner gear cable to hand.

Release the inner cable at the hub end. If the inner is distorted where it was clamped, cut this off with side cutters to prevent damage to the nylon lining of the outer cable. The following document will show how to remove the inner at the shifter end.

Tech doc for revo shifter

With the new RapidFire trigger shift fitted to the handlebars, thread the new inner cable through the shifter and down through the existing outer cable. As the inner cable is threaded through, apply plenty of wet lube to it with your fingers, this will ensure slick downward shifting.

This document shows how the inner cable is fitted to the trigger shifter.


With the new inner fitted, and the trigger shift in 1st gear, set the inner cable length at the hub end to 101 mm, measured from the outer cable ferrule to the center-line of the clamping nut.

 

[JamesC]

I have not found any issues arising from using either of the two shifters with the Nexus/Alfine 8 speed hub.

A new Rapid Fire shifter is normally supplied with a 2100mm cable which is long enough.
eg Petra Cycles or Rose.

As BlewIt says, there should be no problems reusing the old outer casing. However, if you do wish to replace the outer, I used the following technique:

Release the inner at the cassette and pull it out just a little at the shifter - cut off the end so that inner and outer are free of the shifter.

Trim off the frayed bits at the hub end, and thread the new outer over the old inner. Use a few turns of insulating tape to join the two outers. The old inner keeps the casings in line.

Pull the new outer through the frame to the shifter. Fit the new shifter to the handlebars and adjust the new outer cable to suit at both ends.

Finally thread the new inner down through the shifter.

James