by indywagon on Tue Feb 11, 2014 7:14 pm
I'd like to add my experience to this thread:
I bought a new 0 setback Ionic to go on my Cervelo R5 because, like a lot of you, I thought it was a great looking post. It came with both the round and oval clamps. I found that the oval clamps did not firmly hold a 7x9mm Specialized Toupe carbon rail, so I emailed 3T's customer service about the issue. After a bit of back and forth, I received a new, tigher-fitting clamp kit for oval rails, and although it was a bit better than the first, it still was not a secure fit.
I have a Bontrager carbon-railed saddle that I'm pretty sure is 7x10 and it fits fine. I suspect that a Selle Italia carbon-railed saddle, which I think is 7x9.6 would also work with the 3T clamps, but I haven't proven that.
Anyway, my conclusion is that 7x9 doesn't work, which is a pity because it's a very slick-looking seatpost, but anything larger than that is a good bet. I'll probably be putting mine on ebay.
Chris