Yokomo BM-S116TA X-shock tapered piston for B-MAX4  [BM-S116TA]

Asymmetric piston design for handling tweaks

This optional X-shock tapered piston is designed to change the damping balance between extension and compression by making one side of the piston tapered. The asymmetric profile gives tuners a simple mechanical way to bias shock behavior without changing oil viscosity or spring rates.

Orientation is important: place the tapered side up on front shocks to raise front load transfer during deceleration, and orient it down on rear shocks to lower the chance of rear breakaway when the car rolls through a corner. The piston includes six ports arranged in a 1.1mm pattern; a 1.0mm variant (BM-S106T?400) is noted as an alternative in the source.

Introduce this part gradually into setup work: change one piston at a time, run test laps, and log which orientation gives the desired correction to understeer or oversteer. This is an RC-scale shock piston intended strictly for tuning purposes.