The internal rechargeable lithium battery eliminates the user-replaceable coin cell design that characterized earlier Garmin pedal-based power meters. A full charge delivers 90 hours of ride time, which covers multiple weeks of training for most riders. The quick-charge function provides 12 hours of operation from 15 minutes connected to USB-C power, which addresses situations where you discover low battery before heading out. Two magnetic charging clips attach to contacts on each pedal spindle without requiring disassembly or battery compartment access. Travel mode puts the pedals into sleep state during transport to prevent battery drain in travel cases or vehicle mounts.

Pedal IQ smart calibration monitors temperature changes since last calibration, elapsed time, and whether the pedals have been moved between bikes. The system alerts through connected Garmin devices when recalibration would improve measurement accuracy. Manual calibration requires the pedals to be unweighted with cranks horizontal, which takes approximately 30 seconds. The calibration data stores in the pedal spindles rather than the pedal bodies, so it transfers when you swap to RS, RK, or other XC bodies without requiring recalibration.

Force data appears when you pair the Rally XC210 with compatible Garmin cycling computers or smartwatches. This metric reveals how power output responds to cadence changes across different terrain types and effort levels. The data integrates with Garmin's training ecosystem and exports to third-party platforms including TrainingPeaks, Strava, TrainerRoad, and Zwift for indoor training sessions. The pedals work with oval chainrings without requiring special calibration modes or correction factors in head unit settings.

The all-metal pedal body construction handles repeated impacts from rocks, roots, and trail debris while protecting the measurement hardware. The sealed bearing system resists contamination from mud and water, and the bearings follow standard cartridge bearing replacement procedures when worn. The SPD engagement mechanism accepts Shimano two-bolt cleats and works with any SPD-compatible mountain bike shoes. Spring tension adjusts with a 3mm hex key to customize entry and release force based on rider preference and trail conditions.

Spindle swapping between pedal body types requires an 8mm hex key, pedal wrench, and approximately 10 minutes per pedal. The Rally RS bodies use Shimano SPD-SL cleats for road applications, while Rally RK bodies accept Look Keo cleats for riders who prefer that system. This modularity extends the power meter investment across bike transitions or discipline changes without requiring separate measurement systems. Both pedals must use the same body type simultaneously—you can't mix XC and RS bodies on the same bike. The 53mm Q-factor matches most mountain bike cranks, with optional spacer washers available to increase to 55mm if needed for frame clearance.