Ultimate Racing Compak 4 Pro B10: a quick-adjust steel clutch for 1:8 off-road

Photo: Circus RC News (source)

Ultimate Racing unveils the Compak 4 Pro B10, a 4-shoe adjustable clutch that promises to radically simplify clutch stiffness tuning on 1:8 off-road nitro vehicles.

Adjustable without removing the engine

The main strength of the Compak 4 Pro B10 lies in its quick-adjust mechanism: it allows changing the engine clutch stiffness with the engine still mounted, without needing to remove it. Three stiffness levels (I, II, III) are marked directly on the flywheel, with “I” being the softest setting and “III” the hardest.

A 33mm flywheel designed for compatibility

The 33mm flywheel was specifically engineered by Ultimate Racing to remain compatible with most brands on the market. The four aluminum shoes include a linear wear indicator: once the mark disappears from wear, it’s time to replace them. The system is available standalone or bundled with a vented Z13 clutch bell and its bearings.