Shifter for Shimano Nexus 4-speed internal gear hub SG-4R31

BobtheBuilder
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Shifter for Shimano Nexus 4-speed internal gear hub SG-4R31

Postby BobtheBuilder » Tue Apr 17, 2018 7:18 pm

Just wondering if anyone knows a (thumb) shifter compatible with a Shimano Nexus 4-speed internal gear hub SG-4R31.

I picked an old wreck up on Gumtree for $30 and trying to resurrect it.

It has an old shifter on it, but the cabling is completely gone and want to replace whole lot.

Also, if anyone has any tips on testing if the gears are actually working, would be much appreciated.


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Last edited by BobtheBuilder on Wed Apr 18, 2018 6:04 pm, edited 3 times in total.

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MattyK
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Re: Shifter for Shimano Nexus 4-speed internal gear hub SG-4R31

Postby MattyK » Wed Apr 18, 2018 9:16 am

https://www.sheldonbrown.com/nexus4.html

Sheldon Brown wrote:The shift lever for the 4-speed hub may be unavailable, but the cable pull for the shift levers for Shimano 7-speed and 8-speed internal-gear hubs is close enough in the lowest 4 gears that these shifters can be used with the 4-speed.


I'd guess you might be able to use any friction shifter also as a bodge (and as you ask to test the gear functionality) , but I wouldn't recommend it long term without some indexing.

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find_bruce
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Re: Shifter for Shimano Nexus 4-speed internal gear hub SG-4R31

Postby find_bruce » Wed Apr 18, 2018 1:37 pm

This cribsheet by Sheldon Brown is useful - it sets out the cable pull for the nexus 4 speed & why it is close enough for the lowest 4 speeds of the nexus 7 & 8 speed shifters.

You can make a sturmey archer 3 speed shifter work for a 3 speed nexus & they also make a 4 speed thumb shifter which may work, but I haven't been able to find any measurements of the cable pull, nor have I seen any for sale

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10speedsemiracer
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Re: Shifter for Shimano Nexus 4-speed internal gear hub SG-4R31

Postby 10speedsemiracer » Fri Apr 20, 2018 4:10 am

I think you'll be stuck with the replacement RevoShifter, which (for some reason) is readily available from UK sellers.

There are also a few retro-looking Shimano Nexus4 thumb shifters on eBay in various designs.
Mmm, SunTour

BobtheBuilder
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Re: Shifter for Shimano Nexus 4-speed internal gear hub SG-4R31

Postby BobtheBuilder » Fri Apr 20, 2018 10:43 am

Sheldon Brown reckons you can use the first four positions on the Shimano 7- or 8-speed shifters. I hate grip shifters!
But I might first take apart the old one on the bike I have and see if it can be repaired.

But first I need a way to see if the gears actually work.

I am guessing I could just wire up the gear cable and adjust by hand to see if they function, but if anyone knows a way I can check just using the hub, please speak up!

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MattyK
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Re: Shifter for Shimano Nexus 4-speed internal gear hub SG-4R31

Postby MattyK » Fri Apr 20, 2018 11:42 am

The Shimano Alfine 8-speed shifter is a trigger type, not a twist grip. Costs more though.

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