I have a Specialized 2012 (or so) Roubaix Ultegra with a 10-speed cassette. Can I switch to an 11-speed cassette (Shimano Ultegra R8000) by:
1) Taking the old off and putting the new one on, quick and easy, no other adjustments, or
2) Need a conversion kit or special spacers, advanced job, or
3) Not doable. Stick to a 10 Speed.