6mm Rear Drive Belt for Yokomo YZ-4 - Z4-309-6  [Z4-309-6]

6mm belt engineered to cut drag on YZ-4

This 6mm rear drive belt is designed for the Yokomo YZ-4 platform and aims to reduce drivetrain load for RC models campaigned in low-power stock divisions. The narrower profile lowers contact area relative to wider belts, helping to reduce transmission friction while keeping existing chassis geometry intact.

When tuning, fitters use this belt to reduce drivetrain losses and produce a sharper throttle response where motor output is limited. The benefit is typically enhanced when used with a narrow aluminium pulley such as the Z4-630A, which applies contact to a smaller diameter and further reduces drag. That pairing is often selected for tracks that favour short accelerations over extended top speed runs.

Fitting advice: ensure motor pinion, spur and pulley alignment before final tensioning and avoid over-tightening which can increase bearing load. Inspect pulley grooves and running surfaces for damage and verify bearings and idlers spin freely after fitting. This component is intended for model use only.