Welcome to Kedai Basikal Orbit Cycle!
In order to withstand daily riding by top level cyclists, as well as the power of the Di2 front derailleur, the R9100 inner chainring is machined from hardened aluminum, then black anodized for max corrosion and wear resistance. The teeth are highly engineered following Shimano's patented shifting integration system for optimal shift efficiency, chain retention, and wear, and designed with matching precision tothe Hyperdrive tooth profiling system shared with the outer Hollowglide ring. When selecting a new inner chainring, please remember the inner and outer rings are designed as a system, so a 42T inner ring should be only be paired with the proper 54T outer ring. The other combinations are listed below.
Details
Chainring