Engineering advances in the popular 500-horsepower category of road reclaimers/soil stabilizers continued in 2006 with Caterpillar rolling out the RM-500 Rotary Mixer to replace its RM350B. The new 540-horsepower model has a Tier 3 engine with 8% more horsepower than the RM-350B. It also has upgrades in traction, weight balance, serviceability, versatility, and productivity, according to Cat. Key features include full-time all-wheel drive, large tires with aggressive tread, two speed ranges (work and transport), and electronic gear selection. The all-wheel-drive system features two independent variable-displacement propel pumps that supply balanced oil flow to the front and rear drive motors.

Three rotor styles are available. The universal rotor is designed to handle both asphalt reclamation and soil stabilization; it has a 16-inch maximum cutting depth. The application-specific soil rotor has a 20-inch maximum depth; and a combination rotor handles both soil stabilization and light asphalt reclamation