This might be worth a read.
http://velonews.competitor.com/2008/03/ ... -not_73404

Seems to suggest that if it was working ok with Campy levers it should work OK with Sram levers... i think.

http://www.rouesartisanales.com/article-13886600.html

Tuned lightweight RD

Am I missing something? Isn't the derailleur just a spring? Isn't the important thing to match up the shifter with a compatible cassette? Therefore any rear dérailleur would work with any shifter??

Surely the Tune RD will work with any shifter? (a guy in my lbs uses his Lightweight RD with Campag).


Or am I sadly mistaken?

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Schnice

Hey Lard,

Its not that simple. Its also a parallelogram, so that for any certain amount of cable pulled, it moves along the cassette a slightly greater amount. Depending on the amount of cable pulled, the amount the derailleur needs to move varies.

So Campy, Shimano and Sram all have different "ratios" of derailleur movement to cable pull. Now, none of the systems are perfect and sometimes things work, which the companies say shouldn't. So whats the harm in the OP trying? Nothing. But by the numbers it probably won't work but might be close enough.

Some shifter pull a different amount of cable, so the cable displacement combine with the rear derailleur lever make the spacing between cogs..

YES!!! YES!!!!!!!!

I want to beat it though. Last week acquired another RED (pre 2012) RD for experimenting. Not in any rush, I'm going to take my time with this one and really try to push the envelope.

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Exp001

[quote="wshiong
yea on a parlee.[/quote]
Links to it?

Derek:

viewtopic.php?f=10&t=85333

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Exp001

prendrefeu I was thinking the exact same thing . Im going to try and tune my next red RD a bit more .
I think I could dremel a bit more off here and there . Change the spring for a lighter one . it would really need to be pulled to bits to get it at 90 grms . I know of a few guys who work on an old beam engine near where I live . They have access to some awesome engineering equipment and they can strip and rebuild anything . They will help me out . A project for the new year. Did you get one of those bike stands ?. Im now thinking about getting one for my sons retro puch racer .

Mine is almost the same. it use a fiberlyte carbon pulley now.

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Parlee Z3sl - 5 kg

Passoni Xxti- 6.2 kg

I think rd is just a spring, it follow the shifter direction. i will give the sram shifter a try, who knows it will work. I am running on a aftermarket 11s cassate with campy shifter now, and it works fine. although the hand book written it works for 10 speed only.

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Parlee Z3sl - 5 kg

Passoni Xxti- 6.2 kg

This is a really good post . wshiong please keep us up to speed

There's definitely a difference between a shimano shifter pull distance and sram pull. Subtle, but definite. SRAM shifters can present alignment issues by the time you get down to the 1st and/or 2nd cogs on a shimano cassette. That's the difference between 1:1.4 shimano and 1:1.3 sram pull ratios (which as i understand is the combination of the raw shifter movement + the RD lever arm effect of the B section)

I'm also very interested in this as i snagged a tuned LW rd from a fellow member recently (thanks Mike), but haven't bought shifters yet. I'd love to use '13 sram ergos, but if they still have the shortest pull of any shifter, i'm on the fence about it.

I tested, actually it works on sram, but not 100% perfect, even on campy is the same.

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Parlee Z3sl - 5 kg

Passoni Xxti- 6.2 kg