Bicycle Mechanics - shifter/deraillier compatibility
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02-24-11, 10:29 PM
I have recently been building a bike and ran into a problem when I bought shifters. I installed Sram shifters (7 speed) and paired them with a dura ace derailleur. In doing some research I realized that some shifters are 2:1 ratio and others are 1:1. These same shifters would not work with my other bike. The Sram shifters would not work with my front derailleur -It threw the cage too far with each click. All is well for now, but my question is...How does one know if a derailleur isw a 2:1 or 1:1? Do any of you have access to a list of compatible shifters and derailliers. Does such a list exist? Thanks for any insight you can give.
02-24-11, 11:03 PM
The general rule for Sram derailers that are designed to work with Gripshifters is if it has a number in the model name, then it's Sram pull, if not then it's Shimano style.
02-24-11, 11:05 PM
Also, there were a couple of years that Dura-Ace was on it's own planet, I forget what the details are on that one.
02-24-11, 11:11 PM
Thanks, What about older derailleurs? Is there a way to know the ratio or if they will work with modern shifters (both click and twist type)?
02-24-11, 11:15 PM
What's the model name of the derailer? Got pics?
And the number in the derailer model name rule of thumb applies to trigger shifters also, just possibly not the road style shifters, I don't know much about their new road groups.
Sram systems are usually 2:1, Shimano 1:1. Sram makes shifters both ways, but the 2:1 (Sram) ones have numbers for names as in 8.0 9.0, or X.0, etc. and their 1:1 (Shimano) models have names, like Comp, Rocket, etc.
Naturally some time down the line, they'll decide to break the pattern but we'll cross that bridge when we come to it.
Is it flatbar shifters? If they are Shimano compatible, they would be compatible Shimano MTB, not road, which explains why it will not work with a Dura Ace FD. RD should be fine, though.
02-25-11, 03:07 AM
Shimano rear derailers usually have the same cable pull requirements for both road and MTB. There were a few years that Dura Ace derailers were non compatible, IIRC, and you couldn't even use 105 shifters with DA derailers from those years.
Maybe the OP will share model number of DA derailer. I'm curious as to its vintage, considering the use of 7-speed shifters. Seems like the funky DA era was in the 6sp or 7sp days.
Also curious about cassette/freewheel being used.
02-25-11, 03:19 AM
Here's the Dura-Ace rear derailer compatibility chart from Sheldon, under the second bold heading. (http://www.sheldonbrown.com/dura-ace.html)
If I'm reading that correctly and it's a pre-1997 DA derailer we're talking about then indexing may be tricky.
02-28-11, 10:17 PM
Hi, I'm not really sure of the vintage of the derailleurs, but everything seems to be working fine for now. I'll post some pictures. Thanks for your comments. I learn a little more each day. 191811191812
That appears to be an early (pre 9-speed) D-A derailleur. That can be a problem.
Here is a link to some good information about derailleur compatibility, ratios, shifter cable pulls, etc. Some SRAM and Dura-Ace information is included: http://www.ctc.org.uk/DesktopDefault.aspx?TabID=3946
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