Shimano GRX RX810 Crankset

Yes, this crankset is designed for 11-speed systems. However, it features a slightly wider chainline compared to standard road cranks, so you will need to ensure your front derailleur is compatible with the GRX gravel-specific geometry.

Choose the 1x setup (40T or 42T) if you prioritize simplicity, reduced chain drop risk, and less maintenance on technical terrain. Opt for the 2x setup (48/31T) if you need a wider gear range for long road sections combined with steep off-road climbs.

Yes, the 48/31T configuration requires a GRX-specific front derailleur. Because of the wider chainline and the specific tooth difference, standard road front derailleurs will not provide the necessary shifting performance.

Crank arm length is largely a matter of personal preference and bike fit. Generally, 170mm is suitable for shorter riders, 172.5mm is the standard for most, and 175mm is often preferred by taller riders for increased leverage.

While it is optimized for gravel and mixed-terrain, you can certainly use it for road riding. Keep in mind that the gear ratios are tuned for off-road efficiency, so you might find the top-end speed slightly different compared to a dedicated road crankset.