Kyosho UM700 Aluminum Hard Main Chassis

The Kyosho UM700 is the genuine main chassis plate for the Ultima RB6, machined from 7075-T6 aluminum with a hard anodized finish. The chassis is the foundation everything else bolts to, so its stiffness sets how the car transmits load between the front and rear ends and how consistently the suspension works. 7075-T6 is the high-strength aerospace alloy Kyosho specifies here rather than a softer general-purpose aluminum, which is what allows a thin, light plate to stay flat under racing loads.

The hard anodized surface matters just as much: the underside of a 2WD buggy chassis is constantly abraded by dirt and the occasional rock, and hard anodizing dramatically slows that wear so the plate keeps its thickness and stiffness through a season. This is the direct factory replacement for the RB6 chassis, accepting all the original hardware and components. Fit a fresh plate if yours has been bent in a heavy crash, since a tweaked chassis makes the car handle differently left to right.