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PostPosted: Tue Jul 09, 2013 10:11 pm 
Retro Guru
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Joined: Mon Jul 26, 2010 10:46 am
Posts: 503
Location: Leamington, UK
Really struggling with setup on my mb racer.

Newly installed 7spd rsx brifters, 600 rear mech, new 105 7spd cassette.

I just can't get it to shift cleanly up and down the block!

Thought it might be dodgy cable outers so changed them for brand new ones.

No matter what I do I can't get crisp shifting both ways!

Derailleur feels smooth with no play, cable routing is ok.

Really hope it's not the rsx brifters, as I like them and they seem to be in good condition externally, the action is good and they don't stick.

Hope you chaps have some sage words to help me out before I decide to find a NOS 600 rear mech!


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PostPosted: Tue Jul 09, 2013 11:16 pm 
Old School Hero

Joined: Sun Apr 28, 2013 8:56 pm
Posts: 209
Location: Flipping between Wigan and Lincoln
I'd need a little more information here:

1. Is it skipping shifts in one direction or other?
2. Is it failing to shift one way or the other?
3. Are you only having issues at certain points on the cassette?

1 & 2 can be caused by cable tension or dérailleur return spring problems
3 can be caused by B-tension being out or simple limit screw issues.


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PostPosted: Wed Jul 10, 2013 7:48 am 
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Joined: Tue Jun 03, 2008 4:31 pm
Posts: 741
If they are anything like my RSX's they will respond to a damn good clean out and lube. I used contact cleaner the WD40 copy as that's greasier. Perfect now


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PostPosted: Fri Jul 12, 2013 8:54 pm 
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Joined: Mon Jul 26, 2010 10:46 am
Posts: 503
Location: Leamington, UK
So... replaced inner cable for brand new, still no joy.

I can get crisp shifts up OR down but not both, depending on where the adjuster barrel is.

For an experiment I fitted a 7spd xt long cage derailleur and that's shifting much better.

All I can think is that the derailleur I was using (rd-6400 tricolour) is not 7spd compatible, but velobase says it is.

Re: rsx brifters - they spent 2 months submerged in motor oil and another 2 months drying out! There doesn't seem to be anything wrong with them.

Thing is, total cable pull min to max seems right for the width of the cassette.

I think I'm going to try a different 7spd derailleur and see how I get on with that. Not going to let it beat me!


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PostPosted: Fri Jul 12, 2013 9:39 pm 
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Joined: Tue Oct 16, 2012 4:16 pm
Posts: 1568
Location: NOTTINGHAM
I hate these type of bloody inconveniences - i've got the same on some campag running gear and all I did was change the cable - it shifts but 9&10 are the same gear - one press on the ergo and 8th to 10th just like that - but I wanted 9th you ****** thing!

anyway - to your obstinate gearing - how's your chain? If that's worn and you've changed the cassette you could have a few issues with crisp shifting? Or the jockey wheels themselves - if they're worn that again won't be helping the job.

6400 is 7-speed, 6401 is 8 speed & says integrated 8 SIS on the jockey wheel cage.


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PostPosted: Fri Jul 12, 2013 9:51 pm 
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Joined: Mon Jul 26, 2010 10:46 am
Posts: 503
Location: Leamington, UK
Tried 2 chains, the original which isn't too old (still has original grease from packet) but also tried a brand new taya 7/8 speed job...

I'm thinking the derailleur must be at fault if the xt one ahifted ok.


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PostPosted: Fri Jul 12, 2013 9:54 pm 
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Joined: Mon Jul 26, 2010 10:46 am
Posts: 503
Location: Leamington, UK
Nb jockey wheels seem ok too - I swapped for some tacx roller bearing jobs as a test, no difference! Bloody thing!


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PostPosted: Fri Jul 12, 2013 9:56 pm 
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Joined: Tue Mar 23, 2010 11:24 am
Posts: 335
Location: Denmark
And you naturally started with a aligned geardrop? Should be the first thing one does before mounting the rear mech.


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PostPosted: Fri Jul 12, 2013 9:59 pm 
Retro Guru

Joined: Tue Oct 16, 2012 4:16 pm
Posts: 1568
Location: NOTTINGHAM
Sounds like it - you should be able to suss whether the spring return is up to the job with your thumb and likewise the lateral movement on the jockey cage. If it doesn't feel tight and it's easy to push in both movements then it's probably had it's best days.

Daft question but you haven't got too many links in the chain?


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PostPosted: Fri Jul 19, 2013 11:20 am 
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Joined: Mon Jul 26, 2010 10:46 am
Posts: 503
Location: Leamington, UK
I've spent hours and hours trying to fix this. I've narrowed it down to the fact that the derailleur is reluctant to 'spring back' to the correct position when the cable is released (the shifters themselves are fine).

What I am looking for is a Shimano 7-spd compatible rear derailleur (short cage) that has a really strong return spring. So far I've tried

- 7spd Ultegra
- 8spd Ultegra (adjustable spring but max setting is still less firm than 7spd)
- 8spd 105
- Deore XT (best results so far)

NB: I am using new cable with brand new Gore-tex cable outer, but the routing is a bit complicated by the fact that the cable guide braze-on is at the BOTTOM of the chainstay, so the cable has to come out and then round 180deg.

Also I've noticed that in highest gear/most relaxed position the cable seems to be rubbing on the cable outlet of the derailleur. Is this normal?


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