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PostPosted: Tue Sep 11, 2012 10:42 pm 
Old School Hero

Joined: Wed Aug 19, 2009 11:55 pm
Posts: 157
Location: Derby
I've set up a SSP gear system with Simplex RF shifters, and it was working well, until the gear cable came loose under tension. After re-securing it, the rear gears (7-speed block) only selects 1-5. When I try and select 6 or 7, the gear cable just goes loose.

The only thing I'm contemplating at the moment is changing the gear housing from the frame to the RD.

Any ideas? It's took me 10 months to get the parts and build this bike, and this has peeved me to the point of wanting to smash it into a million tiny pieces.

JP


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PostPosted: Tue Sep 11, 2012 11:03 pm 
Gold Trader
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Joined: Mon Jan 15, 2007 11:40 am
Posts: 3000
- if the cable goes slack and the mech doesn't move, then something is either stopping the cable from moving between the place it goes slack and the mech, or something is stopping the mech from moving.
- by "gears 6 and 7" I asume you mean the smallest two sprockets?
- where does the gear cable go slack (parallel to the DT, to the chainstay, or somewhere else)?
- did you check the limit screws on the mech? (if it worked before then I doubt they are the problem, but you never know)
- is the chain seated properly on the jockey wheels?

the easiest solution might be to completely remove the cable, then install it and the outers again as you did when you built the bike the first time.


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PostPosted: Wed Sep 12, 2012 3:19 pm 
Dirt Disciple

Joined: Mon May 07, 2012 2:27 pm
Posts: 46
Location: northampton uk
If you completey disconnect the gear cable does it then go into 7th?


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PostPosted: Thu Sep 20, 2012 11:00 am 
Old School Hero

Joined: Wed Aug 19, 2009 11:55 pm
Posts: 157
Location: Derby
Managed to get some time I the garage today - when the cable securing bolt is loosened on the RD, the mech shifts into 7th. (Smallest sprocket). I have replaced both the cable and the outer, and set up again. Starts off in 7th ok, but after running through the gears, it will only go into 5th, and no higher. The slack is parallel to the downtube. I then remove the cable securing bolt, remove the slack, and re-secure. Unfortunately, the same thing occurs and I think the cable is probably being stretched.

The cable on the chainstay is internal, but I can't feel any friction or blockages.

I'm thinking now, (and I have no evidence for this) is that it might be the Simplex Retrofriction shifters, in that they're not meant for 7.


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PostPosted: Thu Sep 20, 2012 12:11 pm 
Retro Guru
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Joined: Wed Apr 25, 2012 2:08 pm
Posts: 2186
Location: Shrewsbury
Be worth checking everything is nicely aligned and square. Check the hanger and see if the derailleur is parallel with the cogs.

I'd remove the chain and closely check each shift to make sure the upper jockey wheel aligns with the sprocket on each shift.

Is it a good derailleur with plenty of spring tension?


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PostPosted: Thu Sep 20, 2012 1:59 pm 
Old School Hero

Joined: Wed Aug 19, 2009 11:55 pm
Posts: 157
Location: Derby
Just took it out for a spin, to see how it operates under load - jumps badly in gears 4/5 and above, both cogs.


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PostPosted: Thu Sep 20, 2012 2:28 pm 
Retro Guru
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Location: Shrewsbury
blightyinfurs wrote:
jumps badly in gears 4/5 and above, both cogs.


How recently was the chain replaced?


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PostPosted: Thu Sep 20, 2012 9:22 pm 
Old School Hero

Joined: Wed Aug 19, 2009 11:55 pm
Posts: 157
Location: Derby
Chain is new, the rear block is almost new. I'll try a different RD to see how that changes things.


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PostPosted: Fri Sep 21, 2012 9:53 am 
Retro Guru
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Joined: Wed Apr 25, 2012 2:08 pm
Posts: 2186
Location: Shrewsbury
It does all seem to point to the RD. Nice collection of Quinns btw :)


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