#89568 Optional Gear Set
This new ring and pinion gear set provides an optional gear ratio that smooths out power delivery of both 1:8 gas and electric vehicles. Each vehicle type requires two sets. The new final drive ratio introduced by the Optional Gear Set requires a change in your gearing. Please see this link for a helpful conversion chart.
For RC8, RC8.2, RC8.2e, SC8, and SC8.2e kits and RTRs.
Source : Team Associated