Pro-Line Rock-Tek: a magnetic weight system for 1.9″ crawler tyres

Photo: Pro-Line Racing (source)

Pro-Line Racing is tackling crawling’s oldest problem with an unusual solution: the Rock-Tek Tire Weight System (part no. PRO647900) is a tire weight system that mounts magnetically inside 1.9″ wheels, with no need to split the rim.

A 1.9″ tire weight that stays at the bottom

Adding weight to a crawler’s wheels is nothing new: mass placed at the outer edge lowers the centre of gravity and increases the righting torque that brings the truck back onto its wheels. The Rock-Tek principle goes further by mounting the weights on housings fitted with sealed bearings: the ballast does not spin with the wheel, it stays pointing downwards whatever happens. You therefore keep the benefit of low mass even while the wheel turns, which a rigidly bolted weight cannot deliver.

Brass, sealed bearings and N35 magnets

The kit contains two pairs of brass weights at 108g per pair, the composite Rock-Tek housings with their sealed bearings, and a total of 12 N35-grade neodymium magnets to hold everything in place. Soft open-cell foams cushion impacts inside the assembly. On the mounting side, the supplied magnetic hardware is designed to suit the front knuckles of the Axial SCX10 III Portal and the Traxxas TRX-4.

Compatibility, price and availability

The system is announced as compatible with most 1.9″ crawler wheels in 0.8″ width. It is listed at $99.99 at Pro-Line Racing‘s official distributor, currently on backorder with availability announced for September 2026.