256 Direct mount compatibility

[ErikGBL]

There are six different  SRAM XX S2 derailleurs: bottom and top pull of each of the three dimensions corresponding to the chain ring sizes, 39-26, 42-28 and (not so common) 45-30. I have not seen any model name. Each model is characterized by its features, e.g. SRAM XX FD S2, 39, bottom pull. The bottom pull is also often called down pull

The bolt distance is the same for S2 and S3: 21.7 mm. The measure 22.1 mm is the projection of the bolt distance om the perpendicular on the seat tube axis. This distance is also the same for the S2 and S3. This is why I think that the S3 FD also may fit the frame by just putting a 5 mm spacer between the frame and the mounting plate at the front hole. However, I have not tested the S3 on the frame.

S2 bottom pull is only available as XX, but the S3 bottom pull is also available as X0.

[MTB2223]

The holes of the Shimano E2 (S2) fits on these screw holes.

Erik, thank you for your clear explanation.
I made another mistake by thinking the Shimano E-Type2 was a S2 model, but it is a S3 model (and that's why I needed to use a 5mm spacer).

So, the difference between a S2 and a S3 model is the 5mm offset in the mounting plate:


Some information about the difference:
 http://www.cannondaleexperts.com/Cannondale-Flash-Carbon-Direct-Mount-Front-Derailleur-Spacer--KP123_p_803.html

Now I'm going to buy a SRAM X0 FD (S3, 39T, down pull) with 5 mm spacer or a SRAM XX FD (S2, 39T, down pull, EAN/SKU: 00.7615.065.100 ), which is twice the price of a X0.
I'm happy that there is a FD that fits this frame

[MTB2223]

Finally I found a SRAM XX FD (S2, 39T, down pull, EAN/SKU: 00.7615.065.100 ), not new, but unused for the price of a SRAM X0.

I'll replace my Shimano XT FD with te SRAM XX FD tonight.

I'll make before and after pictures.

[MTB2223]

Today I took the time to replace my Shimano XT FD with a SRAM XX FD.

Before:


As you can see the cable is now in a straight line to the FD. I'm really happy with this.


I took the opportunity to made the hole in the frame for the FD cable more dirt proof.
I took some heat shrink/shrinking tube (what are the right words for the dutch word 'krimpkous' ?).
Heated a part of the heat shrink/shrinking tube before installing it.
Put it full with grease and installed it.
Here some pictures:

[MTB2223]

Okay, next (big) problem.

It's not very clear in the last picture, but the FD is in the lowest position. In this position, the chain should be on/above the smallest chainring, but it is now on/above the biggest chainring.
I looks like I need some spacers on the crank And that's not what I want, because the chainline would be horrible, It already make noise when the RD is on the biggest cog and on the front on the biggest chainring. It would be worse.

It now time to going to sleep. Take a good look tomorrow. ... not happy now ....

[Plechovka]

Hi, this is my first post on this great forum so I hope it will be useful
I think the problem is the "D" dimension in "mounting holes dimensions diagram" on previous page. S2 type has D=14.8/17.3mm and S3 only 7/9.5mm, which means that mounting holes for S3 type on frame are closer to chainrings. So if frame is designed to use S3 type (and I don't know if ip256sl is) and you use S2 type derailleur the same problem as yours shlould emerge. But I must say I have no practical experience with this situation, it is only my theory  .

[ErikGBL]

Now I have tested both S2 and S3 FD. Only S2 will fit if you want a good chainline. You could possible use some spacers between the S3 FD and the frame and long bolts, but the spacers must be so long that I am afraid it will reduce the FD performance.

Conclusion: use SRAM XX S2 bottom pull version.

[Carbon_Dude]

Thanks for that info ErikGBL!

[Tiptopperoo]

Is this problem resolved?
Did you manage to get yours working as you want MTB? It seemed like you had the same FD specified by Erik, but it was not working for you? I'm looking to build a 256 and hoping to learn from your experience.

Which is the correct FD to be using on the 256 frame?

Cheers,
Dave

[whitecitadel]

I am also interested in how people are getting on, I have a CS-196 frame (650b) on order from Peter and he pointed me to this thread as being the same setup as the 256 29er frame.

I have bought a M785-E2 Shimano FD, so when I get my frame (still in production) I will see how it fits I guess, looks like with the same wrap around cable setup as others have found with the acute angle. I am running 2x10 so I just hope I can get it smooth.

[MTB2223]

Is this problem resolved?
Did you manage to get yours working as you want MTB? It seemed like you had the same FD specified by Erik, but it was not working for you? I'm looking to build a 256 and hoping to learn from your experience.

Which is the correct FD to be using on the 256 frame?

Cheers,
Dave

Not yet, but I found a SRAM X5 FD which looks like it will fit perfectly, but I have to test this. The lowest position of the X5 is closer to the frame than the XX version.

[ErikGBL]

Here are two pictures of my 256 bike with a SRAM S2 direct mount derailleur: the first picture with the derailleur position on the  outer chain wheel and the other picture with the derailleur in the inner tposition. Shifting is no problem at all. I am using SRAM chain wheels (39T/26T) on a Lightning crank. I have also used a Specialized crank with same good result.