What are the key differences between Shimano Ultegra R8000 and 6800 groupsets?

The key differences between Shimano Ultegra R8000 and 6800 groupsets are improved shifting performance, lighter weight, and enhanced braking power in the R8000 series compared to the 6800 series. The R8000 groupset also features a more streamlined design and updated technology for smoother and more efficient cycling performance.