Putting 11-34t cassette on CX Bike
My son-in-law recently bought an used Cannondale CX bike with Ultegra Rear Derailleur, 11-28t cassette and FSA 50-34 Crank. We live in an area with some pretty steep long gravel climbs and he would like to make it more climbing friendly. I called Shimano and they informed me that the biggest cassette that we could put on with a long cage rear derailleur is a 11-30t. Does anyone have any experience or suggestions? Thank you for your help.