Traxxas TRX-4M 1/18 Rock Crawler w/Ford Bronco Body Black RC18 Parts Kyosho describes the purpose directly:

Kyosho describes the purpose directly: the weights attach to the front knuckle to increase tire load and change steering response

028 sec/60 deg

including compatible Castle Creations

they are built to withstand high-speed bashing and everyday driving

Traxxas TRX-4M 1/18 Rock Crawler w/Ford Bronco Body Black RC18 Parts Kyosho describes the purpose directly:Traxxas TRX 4M 1 18 Rock Crawler w Ford Bronco Body MODEL 97074 1: TRX 4M Scale and Trail crawler with Ford Bronco body: 1 18 4X4 trail truck, fully assembled, Ready To Drive, with TQ 2. 4 GHz 2 channel transmitter, and ECM 2. 5 waterproof electronics. Whats In The Box: TRX 4M Ready To Race model Licensed ABS hard body Titan 180 87 turn motor ECM 2. 5 Electronic Control Module TQ transmitter 7. 4 volt 750 mAh 2 cell LiPo battery 2 amp USB fast charger