Rear Derailleur Problem with 6/7/8 speed - Please help!!!!!

emulsifier12

New Member
Location
Nuneaton
I have just built up a dawes galaxy tourer and used the original rear derailleur that was fitted to the frame when I bought it. It is a Sachs Huret Rival Touring Derailleur which I have cleaned up and which is working well, but it is only able to select 7 out of 8 gears on the rear cassette using a 6 speed shimano stem shifter in friction mode. I am using an 8 speed shimano cassette HG40 on a shiamano hub with 130 OLN (Rear Drops).

The derailleur can reach all 8 gears when I push it over by hand, but it seems that the stem shifters are not pulling enough cable to get to the 8th gear?

Is the problem the 6 speed stem shifter in friction mode or is it the derailleur which is about 20 years old and was designed for 6 speeds?

Will a new derailleur eg. Shimano TX31 Tourney Derailleur 6/7 speed work? The reason is that they are on special for £6 at Halfrauds and I can pick one up tomorrow and use it over the bank holiday weekend.

Is there a difference between a 7 speed derailleur and a 8 speed one?

I have attached pictures of the bike and rear derailleur below.
 

Number14

Veteran
Location
Fareham
If the derailleur can reach all 8 gears when you push it by hand then the shifter is the problem. The shift lever will only have enough travel for the six gears. You need another shifter with agreater range of movement.
 

stevepratt48

New Member
Agreed - the issue is cable pull - you might get away with it if you are very careful in removing all traces of slack....... (reduce outer cable to a minimum, as this also compresses ever so slightly.) I've used all sorts of combinnations in the past, always got them to work!!
 
OP
emulsifier12

emulsifier12

New Member
Location
Nuneaton
Following your advice on adjusting the cable etc I managed to get it to just select the 8th gear, but as soon as any pressure was put on the gears by riding it it would jump between 7 and 8.

I therefore bit the bullet and bought a cheap shimano tourney for £6 from Halfrauds. I set it up and it selected 1 - 8 with ease. There is about 7 or 8 degrees of movement available on the stem shifter still.:smile:

My conclusion : The old derailleur had a slightly different cable pull to lateral movement ratio to the shimano.

All sorted now, thanks for the replies. Now I can start looking for affordable shimano drop bar 8 speed sti's... anyone got any for about £50 they would like to sell me?
 
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