7 speed indexing problems???

[legrandefromage]

DA shifters can be a bit fernickerty when mixing up MTB and road rear mechs

The rear mechs are 'supposed' to be only used with DA but then Ultegra appears to work too and is often mentioned as compatible in the literature

front mechs are just a minefield of cage width, reach, cable pull etc etc - I only ever use bar-end shifters with MTB front mechs or at least a road triple if trying to index up some brifters

 

[2manyoranges]

There’s this very useful article which includes a table:

http://blog.artscyclery.com/science...ce-behind-the-magic-drivetrain-compatibility/
And these state that Dura Ace is a bit of a different affair - and in different times....

Shimano Dura Ace from 1984 to 1996 period (6 to 8 speeds)
Rear shift ratio is 1.9. They are compatible only with Shimano Dura Ace shifters from the same period (that is for 6, 7 and 8 speeds).

From Bike Gremlin.

And from Sheldon Brown....

Dura-Ace went through multiple generations, from 6-speed, through 7-speed and 8-speed through the 1996 model year.

1997 was a very big year for Dura-Ace. The system went to 9 speeds, and that was the most publicized change. In addition, however, the entire Dura-Ace system was redesigned and made to be inter-compatible with other Shimano components.

So...as for so many things about drive trains....it all depends on the specific bits which you have in hand....

 

[2manyoranges]

We ran bonkers tiny cage 105 road rear mechs on our mountain bikes during the 1990s - the period of much weight obsession - and polished the heck out of them so no one knew what they were. This gave excellent ground clearance, brilliant shifting, and the need to remember precisely which front-rear gear combinations were possible without totally screwing your drive train and potentially bending the rear hanger, or even the entire rear triangle. Mostly, all middle ring-rear were fine, and you just had to be careful at the extremes of front and rear, which was fine in practice. It looked mental. And it could never have been put on a retail bike since it was so potentially hazardous to bike and rider. Fun though.

 

[legrandefromage]

I ran short mechs to stop the chain flapping around

 

[2manyoranges]

Good point Big Cheese - yes, much better chain tension, too mainly to do with shorter length chain, but also the mechs all seemed to have much the same cage spring tension, (same parts for economic production?) so running a short cage meant better leverage in the mech acting on the chain, keeping it tighter. I tried to play with different cage springs once. Never again. They must have a special jig in the factory to get them in. Nightmare job. Many cuts to finger. Much profanity.

 

[benjabbi]

@2manyoranges a bit like this

 

[chambo34]

I think most 7/8 speed short cage derailleurs work up to 28t

 

[chambo34]

Just got back, still the odd jump, I'll check the chain over again when it's dry for tight spots, if that fails to provide an answer I'll pop an unused Deore Lx I have from the mid 90s on it and see if that's any better.

 

[2manyoranges]

Benjabbi...oooh....oooh....that’s looks jolly nice....

Chambo....they may work up to 28T but the RANGE means that some combinations of front and rear - eg 48-28 which would be stupid but possible to do - under load would yank the chain so tightly that the mech would instantly bend and put enormous strain on the frame. And IIRC we were running 32s on the back at the time and just pushing everything to the limit...

 

[chambo34]

Never had anything bigger on the back than a 30, son in law has (I think) 11-42 on his hybrid with I think a 34t up front, it can climb but he's spinning like Billy O on the downhills