Lightweight Rd on Sram

Discuss light weight issues concerning road bikes & parts.
JamieL
Posts: 381
Joined: Tue Jun 21, 2011 1:05 pm

by JamieL

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.


by Weenie


User avatar
LardLover
Posts: 282
Joined: Sun Apr 26, 2009 2:21 pm
Location: Kingdom Of Northumbria

by LardLover

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?? :shock:

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? :roll: :oops:
Schnice :cool:

NGMN
Posts: 1536
Joined: Mon May 30, 2005 7:13 am

by NGMN

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.

zambony
Posts: 38
Joined: Fri Apr 15, 2011 8:52 pm

by zambony

LardLover wrote: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?? :shock:

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? :roll: :oops:

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

User avatar
prendrefeu
Posts: 8587
Joined: Wed Oct 31, 2007 10:32 pm
Location: Los Feliz, Los Angeles, California
Contact:

by prendrefeu

artray wrote:http://www.rouesartisanales.com/article-13886600.html" onclick="window.open(this.href);return false;

Tuned lightweight RD :thumbup:


YES!!! YES!!!!!!!! :twisted:

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.
Exp001 || Other projects in the works.

dmp
Posts: 322
Joined: Fri May 08, 2009 8:31 pm
Location: Denver

by dmp

prendrefeu wrote:
artray wrote:http://www.rouesartisanales.com/article-13886600.html" onclick="window.open(this.href);return false;

Tuned lightweight RD :thumbup:


YES!!! YES!!!!!!!! :twisted:
.

http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=7&cad=rja&ved=0CEsQtwIwBg&url=http%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3Db0OeM6UUAoI&ei=rDDSUNvFHIeuqQHtmIDIBg&usg=AFQjCNEpEeG5hb6Zpe6Agjygdq5OgUw_-g&bvm=bv.1355534169,d.aWM

dereksmalls
Posts: 1977
Joined: Tue Aug 02, 2011 9:20 pm
Location: New Zealand

by dereksmalls

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

User avatar
prendrefeu
Posts: 8587
Joined: Wed Oct 31, 2007 10:32 pm
Location: Los Feliz, Los Angeles, California
Contact:

by prendrefeu

Exp001 || Other projects in the works.

artray
Posts: 1365
Joined: Fri Oct 07, 2011 2:08 pm

by artray

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 .
Last edited by artray on Thu Dec 20, 2012 4:27 pm, edited 1 time in total.

User avatar
wshiong
Posts: 503
Joined: Tue Oct 12, 2010 4:00 pm
Location: MY

by wshiong

artray wrote:http://www.rouesartisanales.com/article-13886600.html" onclick="window.open(this.href);return false;

Tuned lightweight RD :thumbup:


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

Passoni Xxti

User avatar
wshiong
Posts: 503
Joined: Tue Oct 12, 2010 4:00 pm
Location: MY

by wshiong

JamieL wrote:This might be worth a read.
http://velonews.competitor.com/2008/03/ ... -not_73404" onclick="window.open(this.href);return false;

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


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.
Passoni Mirror

Passoni Xxti

artray
Posts: 1365
Joined: Fri Oct 07, 2011 2:08 pm

by artray

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

UpFromOne
Posts: 648
Joined: Wed Apr 08, 2009 5:23 am
Location: Olympic Nat'l Park, WA

by UpFromOne

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.

by Weenie


User avatar
wshiong
Posts: 503
Joined: Tue Oct 12, 2010 4:00 pm
Location: MY

by wshiong

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

Passoni Xxti

Post Reply
  • Similar Topics
    Replies
    Views
    Last post