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

Lightweight 6mm rear belt for YZ-4

This is a 6mm width rear drive belt designed for the Yokomo YZ-4 platform, intended to reduce drivetrain load on RC-scale models running in low-power stock categories. The narrower belt lowers contact area compared with wider belts and can reduce friction in the transmission path without altering the chassis layout.

In tuning terms, this belt is used to trim drivetrain resistance and sharpen throttle response where motor power is limited. Effects are most noticeable when combined with a narrow aluminium pulley such as the Z4-630A, which concentrates contact on a smaller diameter and can further reduce drag. This combination is commonly chosen for tracks that demand quick, short bursts rather than sustained high speed.

Installation notes: check alignment of motor pinion, spur gear, and pulleys before finalizing belt tension, and avoid over-tensioning which can increase bearing load. Inspect pulley grooves and running surfaces for wear, and confirm smooth rotation of bearings and idlers after fitting. This is an RC-scale accessory intended for model use only.