Subject: Re: Shimano Front Derailleur 8/9 speed compatability Posted by: Al on July 18, 2006 at 15:00:40: In Reply to: Shimano Front Derailleur 8/9 speed compatability posted by Eddie on July 18, 2006 at 08:26:23:

Message: >Forgive me in advance if this question has already been answered in this forum (I searched, but didn't find). I have an 8-speed Shimano drivetrain (XTR chain, XTR rear derailleur, 46T four-arm XTR cranks). I need a new front derailleur due to a frame change. In terms of what's out there for sale, I mostly see newer front derailleurs (M751, for example) "designed specifically for Mega 9." Question: Is a 9-speed front derailleur NOT compatible with my 8-speed drivetrain? I currently have a shimano M739, top swing top pull, but I can't find that vintage for purchase...What are my options, if I want to avoid the cost of replacing other parts of the drivetrain? Thanks for your assistance! You should be able to get a "new"/replacement 8-speed front derailleur on eBay ... The 9-speed chain is narrower than the 8-speed chain ... The 9-speed front derailleur cage plates are CLOSER together than the 8-speed plates ... Despite what some people think, mixing 8-speed & 9-speed chains & front derailleurs will only result in balky shifts when using a triple crank -- YOU WANT TO MATCH THE CHAIN TO THE FRONT DERAILLEUR ... You may be able to use the 9-speed front derailleur if you use a 9-speed chain ... but, I can't guarantee that your 8-speed shifter won't move the front cage an extra 0.1mm (it doesn't sound like a lot, but it CAN be). Maybe it will work. FWIW. The MECHANICAL difference between an Alivio front derailleur and an XT negligible, and it is mostly a cosmetic difference (e.g., nicer clamp on the XT, of course) ... I do remember reading that there is something about _one_ of the XTR front derailleurs, but that may have been related to a 9-speed version of one of those E-mount front derailleurs. So, you could PROBABLY use _any_ 8-speed Shimano front MTB derailleur if the clamp size is suitable AND the pull is appropriate for your frame's cable routing.