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Discussion Starter · #1 ·
I am looking to purchase a new front derailleur for a new bike I am building. I will be running a 2x9 setup on this bike. I have noticed that Shimmano has a couple of front derailleurs that are made specifically for 2x9 drive trains. Is there any performance advantage to running one of the 2x9 specific derailleurs over a standard one?
 

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ups and downs
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The SLX dual chainring cage is shorter so you do have more clearance to the tire and swingarm if it's a suspension bike or a 29er. And it does drop the cage closer to the bashring so it keeps everything tidy. You have to use the SLX for 48-50mm chainlines and the Saint for the wider DH/FR chainlines they aren't interchangeable.
 

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Front derailleurs cages are designed based on the number of chainrings, range between small and large chainring, and the size of the largest chainring. A road FD that is designed for a 52 tooth chainring will not fit a 32T ring as closely a MTB FD. This can make it harder to setup and adjust.

A road 2x9 FD should be different than a MTB 2x9 FD. While a road FD can be made to shift well on smaller gears, it will still be harder to adjust and have a larger gap between the cage and big ring or bashguard.
 

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Yeah, I guess we should have asked, is this a XC or FR 2 ring setup? 30/42 or 26/36? If it's the former road derailleurs will work fine. If the later, get a Saint or SLX 2 ring derailleur or keep using your 3 ring derailleur cuz I don't see any advantage to the MTB 2 ring ones.
 

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Discussion Starter · #8 ·
Lelandjt said:
Yeah, I guess we should have asked, is this a XC or FR 2 ring setup? 30/42 or 26/36? If it's the former road derailleurs will work fine. If the later, get a Saint or SLX 2 ring derailleur or keep using your 3 ring derailleur cuz I don't see any advantage to the MTB 2 ring ones.
It will be a 22x34 setup on a 2008 Turner Spot. It needs to be a traditional down swing / top pull front derailleur. Turner recomends the Shimano M971. I am going to email Turner to see if the SLX will work on the Spot.
 

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The SLX will work fine and is only 15 grams heavier than the XTR they recommend.

P.S. I have 2 rings and a E13 DRS with bashring (works great but they are coming out with a "much improved" model) on my FR bike and I gotta recommend going up on both your chainrings. If you have a 11-34 cassette the 22 ring makes for a uselessly low first gear. Also you will spin out the 34/11 combo on mellow flats. I run 26/36 and only rarely wish I had a slightly lower first gear. The 36 gets me by okay but I sometimes spin it out and have trouble keeping up with guys on triples. So even if you aren't a great climber I'd recommend 24 or 26 and 36.
 

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A road front derailleur will save you weight. It will also help you if you are running a really short bottom bracket axle length. Forexample a 108mm bottom bracket w/ a 2x9 setup. Sometimes bikes with bigger diameter seat tubes when using a normal mountain bike front derailleur you can not adjust the L screw enough to get the derailleur cage close enough to your seat tube to allow the chain to downshift to your smallest chainring in the front. THat is when a road derailleur will help you out the most.
 

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weight weenie
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Cheers! said:
A road front derailleur will save you weight. It will also help you if you are running a really short bottom bracket axle length. Forexample a 108mm bottom bracket w/ a 2x9 setup. Sometimes bikes with bigger diameter seat tubes when using a normal mountain bike front derailleur you can not adjust the L screw enough to get the derailleur cage close enough to your seat tube to allow the chain to downshift to your smallest chainring in the front. THat is when a road derailleur will help you out the most.
Sorry to bump an old thread but I have the opposite problem. Im using a Dura Ace 7900 FD with 29/44 FSA K-Force Light crankset and Sram X.0 thumb shifters. I can't get the cage long enough out. It will shift to the larger chainring but there is a major chain rub to the cages outer side. I have screwed the adjustment screw all the way out. Any suggestions?
 

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elasto said:
Sorry to bump an old thread but I have the opposite problem. Im using a Dura Ace 7900 FD with 29/44 FSA K-Force Light crankset and Sram X.0 thumb shifters. I can't get the cage long enough out. It will shift to the larger chainring but there is a major chain rub to the cages outer side. I have screwed the adjustment screw all the way out. Any suggestions?
Get a mtb FD. They have more outward throw.

And SRAM has never made thumb shifters
 

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So sorry for the wrong term! I meant triggers of course (not sure why they call the SRAM ones "triggers" because you don't use your index finger with them, just thumbs?).

I was looking for some more helpful suggestions to my problem than to just change the whole part. Many people use road front derailleurs on their mountain bikes. Sure you can fix any problem by just changing the whole part but I want to tune my derailleur to work if possible. I will be going back to the WW forum now. Maybe I can get more help from there.

Bye. :drumroll:
 
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