I am in the process of building a 2011 S-Works Crux with an Ultegra 6800 group set that I have lying around.
The frame is for a clamp-on fd, the seatpost however has a 35.8mm diameter where the clamp would go.

Problem is, I cannot find Shimano offering a 35.8 mm clamp-on fd. I only find a 34.9.
Before buying can someone tell me whether the 34.9 would fit? Is that within the tolerance?

Thanks for any adise.