....I had a long technical discussion with Jo Klieber (engineer behind Syntace) about 4 bolt stems last summer:
any 4 bolt stem stresses the handlebar more than conventional 2 bolt faceplate stems.
There's even more stress with two divided clamps (like on the F99 or the new Ritchey WCS V3), because the clamping force applies in a very small area.
He had several 4 bolt stems from different manufacturers (incl. his F99) on his testing machine and all stems cracked handlebars earlier than 2 bolt designs.
That's why he decided to reinforce his bars in the clamping area and strongly recommends to use only bars which are explicitly approved for 4-bolt use by the manufacturer....
I'll second that! And I guess that there's more stress on the 4-bolt divided clamp itself, too, because I cracked my Deda Newton today, sheared at the top two bolts...had checked the torque when I last overhauled, it seemed alright.
Too bad...Anyone have any suggestions on a good new 31.8 stem, light and reliable and strong?
(Deda Newton bars, I don't really want to change them right now, but of course bar/stem suggestions also welcomed).