Nexus 4 speed help

[Ed_Straker's_Rat]

I am going to build a replacement shifter for my Shimano Nexus 4 speed hub and I was wondering if anyone out happens to know how far the cable travels for each gear shift? I tried a couple of the 3/5 speed shifters I have kicking around but the hub always seems to be out of adjustment and I don't want to strip any gears. I even tried an old friction shifter but I can't tell when the gear is engaged properly.

I tried my LBS and the internet but the Nexus-4 was discontinued so I can't buy a replacement. If I could get the correct cable travel (in mm hopefully) then I can rig an index shifter with a ball bearing and spring.

I totally trashed my old one when my router fell off a high shelf and hit it. Luckily it took the full force and left the bike pretty much untouched.

Cheers, Simon

 

[rick74304]

Simon, if it were me, i'd flip the bike over and break out the measuring tape. Have someone help by slowly turning the pedals while you hold the measuring tape against the axle and try shifting by pulling on the chain. You should be able to get each distance roughed out. Confirm the numbers by measuring the distance from 1st (the gear the hub rests in under no load) to 4th, then divide that by 3. That should give you the distance of travel between each gear.
If you have an old indexed shifter kicking around (the kind that uses a bearing that rolls from hole to hole, thereby trapping the shifter in gear) making a new plate for it with the hole distance you need should be pretty straight forward.
Keep in mind, even though its a 4 speed, it only needs 3 shift notches, because the hub always rests in 1 gear.
Hope that helps,
Rick