YZ-4 Compatible 6mm Rear Drive Belt for Track Use - Z4-309-6 by Yokomo  [Z4-309-6]

Narrow 6mm belt tuned for YZ-4 performance

The Z4-309-6 is a 6mm width rear drive belt engineered for the Yokomo YZ-4 platform to reduce drivetrain drag on RC-scale cars running in low-power stock categories. By reducing the belt contact patch compared with wider belts, it can lower friction along the transmission path without requiring chassis alterations.

From a setup perspective, riders use the narrow belt to trim drivetrain losses and sharpen acceleration response where motor power is constrained. The effect becomes more pronounced when combined with a narrow aluminium pulley like the Z4-630A, which concentrates contact on a smaller diameter and helps reduce rolling resistance. This combination favours circuits with short, sharp acceleration demands.

Fitting notes: confirm alignment of motor pinion, spur and pulleys before locking tension, and avoid excessive tensioning which increases bearing loads. Check pulley grooves and running faces for wear and make sure bearings and idlers rotate freely after installation. This product is intended solely for model use.