I run 52-39-26 on two 9-speed bikes and one 10-speed bike using Ultegra FDs. One of the nine-speeds is a braze-on, which runs a 12-27 in back. The 10-speed runs an 11-25. The other 9-speed runs a 12-34. None of them have any problems. Of course one never runs the granny ring below the 4 largest cogs and the big ring above the 3rd largest cog, though the chain is always set to not break the RD plus 1 link at big-big.