Kyosho TF021 Upper Plate TF-5 RS

This is the upper deck plate for Kyosho's TF-5S and TF-5 Readyset chassis.

On a touring car the upper deck is a genuine tuning component rather than just structure. It ties the front and rear bulkheads to the chassis and controls how much the car twists between the two ends, and that torsional stiffness determines how quickly weight transfers across the car in a corner. A stiffer deck makes the car respond faster and feel more direct; more flex lets the chassis absorb surface irregularities and can find grip on a low-bite or bumpy track.

That is why touring car racers pay attention to upper deck configuration in a way buggy racers generally do not, and why some cars ship with more than one option.

It also takes structural load and is exposed in a crash, so a cracked deck changes chassis stiffness quietly, before it becomes obvious. Worth inspecting after a heavy impact rather than assuming it is fine because the car still drives.

Kyosho lists this for the TF-5S kits and TF-5 Readyset cars, not the original TF-5 kit.