New lever compatibility

[kempysixseven]

Hi.

Currently in the mood to revitalise my commuter (a 2004 Specialized Allez Elite / w 105 9speed group) and wanted to know if that by changing ONLY the levers and associated shifters to a newer style (one that enables cable routing to flow under the bar tape) , will new be compatible with old?
I don't wish to change complete Group as the derailers still work a treat (as do the shifters actually - but understand they need to go with the brake levers).
Not fussed about staying berand consistent either - setup just needs to work and look pretty.

Any help / advice greatly appreciated!
Rich

[ldrcycles]

If the new shifters are also 9 speed then no worries, i think 10 speed have a different cable pull and might not work with 9 speed derailleurs?

[waynohh]

I don't think you'll find 9sp shifters with internal cable routing sorry. The current ultegra and 105 only just got it.

[pawnii]

i'm pretty sure you can use Dura-ace 7700, Ultegra 6700 and 105 5700 shifters on 9 speed cassettes and derailleurs. (all under bartape cable routing)
Shimano haven't changed the mechanical pull ratio on there shifters for the last 3 generations. They change the mechanical pull ratios on the derailleurs to suit 9 or 10 speed cassettes. Front derailleur will work fine also
It's just a matter of tuning it correctly.

[MichaelB]

i'm pretty sure you can use Dura-ace 7700, Ultegra 6700 and 105 5700 shifters on 9 speed cassettes and derailleurs. (all under bartape cable routing)
Shimano haven't changed the mechanical pull ratio on there shifters for the last 3 generations. They change the mechanical pull ratios on the derailleurs to suit 9 or 10 speed cassettes. Front derailleur will work fine also
It's just a matter of tuning it correctly.

I think you are wrong there pawnii.

9 speed shifters need to stay with 9sp rear cluster. The shifters that have all under bar tape cable runs are the new 7900/6700 and 5700 setups and these are not compatable with 9sp.

HOWEVER, if you slap on a 10sp casette along with those levers, you'll be fine. Expensive way to get 1 extra gear though.

[pawnii]

thanks for the correction MichaelB.
i'm wrong...once again

It's only the derailleurs that is compatible between 9 and 10 speed groupos

Here is the compatibility chart
http://bike.shimano.com/publish/content ... le.html/01)%20Drivetrain%20Compatability%20Chart.pdf

[waynohh]

A derailleur is just a cage, spring and pulleys in the case of the rear, it has no concept of indexes.

[pawnii]

if that was true you would be able to mix and match rear derailleurs between different manufacturers.

[ldrcycles]

A derailleur is just a cage, spring and pulleys in the case of the rear, it has no concept of indexes.

Does this mean a pre indexing derailleur will work with indexed shifters? I'm sure i remember seeing something somewhere to the extent that Shimano pre indexing and 1st gen indexed derailleurs had less movement per mm of cable pull than later ones?

[waynohh]

if that was true you would be able to mix and match rear derailleurs between different manufacturers.

"pull ratio" != "index"

Pull ratio is a function of the derailler. X cable in = Y parallelogram movement out. Simple as that. Use a 9sp derailleur with 10sp shifters if you like as long as the ratio is the same.

Index is a function of the shifter (and depends on cassette). A 10 speed shifter pulls a different amount of cable for each index than a 9 speed shifter because the spaces between sprockets is different.

So you can't use a 10sp lever with hidden cables without changing cassette, which also mean replacing chain also. Shimano are sometimes fond of changing the pull ratio of the front derailleur and brakes too, so it's possible those can end up compromised.

[Mulger bill]

A derailleur is just a cage, spring and pulleys in the case of the rear, it has no concept of indexes.

Does this mean a pre indexing derailleur will work with indexed shifters? I'm sure i remember seeing something somewhere to the extent that Shimano pre indexing and 1st gen indexed derailleurs had less movement per mm of cable pull than later ones?

A derailleur (with the exception of some examples such as the Shamino Airlines pneumatic) is a simple machine that will do exactly what the control device tells it to do. The thing is, as you mentioned, different makers have chosen slightly different leverage ratios which mean different makers index shifters will not work with them. IIRC, early index shifters by Shamino could have the indexing function isolated so that they could function as friction shifters if needed. Friction shifters are also simple machines that do exactly what the control device (your hand) instructs, cable pull is irrelevant to them, you just move the lever far enough to achieve the desired result.