Shimano Ultegra Di2 R8150 12 Spd Front Derailleur More compact and faster than ever, the ULTEGRA R8150 front derailleur performs digitally precise front shifts under any circumstances. Combining Shimano's new Di2 platform and the road incarnation of HYPERGLIDE+, the ULTEGRA R8150 front derailleur shifts between chainrings with our fastest, most seamless action. Our fastest ever front shifting, 45% faster than FD-R9150 Smaller, sleeker, lighter Frontal area reduced by 33% Weight cut to 116 g Top gear teeth capacity: 50-54T