Shimano Nexus 7 shifter replacement problem

[fredgroom]

hi folks

i have a bike with shimano nexus 7 hub gears and a broken shifter. i replaced the shifter but it seems that the shifter is not completely compatible with the gear system. the shifter is a shimano 'revoshift' 7 speed.

however i calibrate i loose one end of the gears, and position 3 and 5 on the shifter either do not change or the gears jump around, the rest of the positions hold the gear well.... e.g.

shifter - gear
1 - 1
2 - 2
3 - -
4 - 3
5 - -
6 - 5?
7 - 6?

so it seems that the distance the cable is pulled by the shifter for each click, is not the same as the distance the cassete joint pulley needs to move to change one gear.

it seems odd that the two would not be compatible with each other as they are both shimano and 7 speed etc.

can anybody help?

cheers!

fred

[nfmisso]

Hi Fred;

The problem is that the Revoshift without Nexus in its name is for a derailleurs, not hub gears; and of course Shimano being ______ the travel is different between the two.

I got caught the other way around when I found a Nexus 8 speed shifter for an incredibly low price...

You need one of these:
http://www.amazon.com/Shimano-Nexus-7S10-7sp-Revo-shifter/dp/B000R3CBRU/

[fredgroom]

a ha i see... that would definitely explain it...

what nice people they are, with our best interests at heart

thanks a lot for a quick reply nigel, much appreciated!

fred

[trevgbb]

This is the Shimano EU site, read the tech docs for your components;
http://cycle.shimano-eu.com/
and shifter is;
http://techdocs.shimano.com/media/techdocs/content/cycle/SI/Nexus/ShiftLever/SL-7S20/6M50B-001_SL-7S20-EN_v1_m56577569830649643.pdf