S1, S2, S3 front derailleurs

[dlorga]

What is the difference? Does it have to do with chainring size?

[shiggy]

What is the difference? Does it have to do with chainring size?

Three different direct mount "standards."
BTI-USA.com has more details. They list at least three versions of each among the 22 versions of the XX FD.

[dlorga]

I'm still confused, the 2011 Spec. Stump. FSR Comp 29 comes with a DMD X7 ( I don't know wich ) and 33/22 chainrings. If I wanted to go 39/26 or 38/24 wich front derailleur should I get?

[frdfandc]

According to Specialized website, the Stumpy FSR Comp 29er uses a Shimano SLX for the "custom" SRAM crank. Its a direct mount style description, but its an E-Type FD that mounts in between the BB cup and frame.

http://www.specialized.com/us/en/bc/...cname=Mountain

Pulled from Specialized website

"Shimano FD-M660-E SLX, double specific E-type for DMD, top swing, bottom pull"


Since SRAM doesn't offer this crank as an aftermarket replacement, you will have to choose the FD that will work best with the crankset you choose.

If you look at the following, you will see what you need.

S1 is for 26-39
S2 is for 28-42
S3 is for 30-45

[shiggy]

According to Specialized website, the Stumpy FSR Comp 29er uses a Shimano SLX for the "custom" SRAM crank. Its a direct mount style description, but its an E-Type FD that mounts in between the BB cup and frame.

http://www.specialized.com/us/en/bc/...cname=Mountain

Pulled from Specialized website

"Shimano FD-M660-E SLX, double specific E-type for DMD, top swing, bottom pull"


Since SRAM doesn't offer this crank as an aftermarket replacement, you will have to choose the FD that will work best with the crankset you choose.

If you look at the following, you will see what you need.

S1 is for 26-39
S2 is for 28-42
S3 is for 30-45

Not quite.

As per BTI:
(XX) available in three versions: S1 for 42.7mm, S2 for 22.7mm, or S3 for 22.1mm mounts

Then each mount version has 2 versions for different chain ring sizes, plus there are dedicated top pull and bottom pull versions of each of those.

In the X-7 I see three versions each of the S1 and S3 (no S2).

dlorga, the specs are on the site. Go look.

[frdfandc]

Thanks for the update Shiggy. I was going off SRAM's site, and of course they have missing information.

[shiggy]

Thanks for the update Shiggy. I was going off SRAM's site, and of course they have missing information.

SRAM has a crazy number of FD versions. BTI Lists:

22 for XX
28 X.O
24 X.9
16 X.7

And those are just For the 10-speed groups.

dlorga, I bet your current FD will work.

[dlorga]

check this out: Specialized Technical Bulletin on 2011 SJ FSR Expert and Comp 29er
I don't have that bike yet, I wanna buy it, but I have to figure this out first, cause I need bigger rings, and the X7 that is coming on the bike does not look like it could be moved up to accomodate bigger rings.
Help me out guys. Thanks.

[shiggy]

check this out: Specialized Technical Bulletin on 2011 SJ FSR Expert and Comp 29er
I don't have that bike yet, I wanna buy it, but I have to figure this out first, cause I need bigger rings, and the X7 that is coming on the bike does not look like it could be moved up to accomodate bigger rings.
Help me out guys. Thanks.

I have no more info.

The only bike pic I saw in that thread had the FD WAY high over the rings. Plenty of room for a 38T ring.