🏎️ RC Tuner — Chassis Geometry

How to measure: Use digital calipers. Measure from chassis centerline (X) and from axle line (Y) to centerline of each hinge pin/ball stud. For Y: measure from bottom of chassis to top of pin, subtract half pin diameter. Partial disassembly may be required.

Shimming inner pickup points changes the arm angle, which moves the instant center:

• Raise inner upper → upper arm angles down → IC moves down → lower roll center → more camber gain
• Lower inner upper → upper arm angles up → IC moves up → higher roll center → more jacking
• Raise inner lower → lower arm angles down → IC moves up → higher roll center
• Lower inner lower → lower arm angles up → IC moves down → lower roll center

Roll center height affects jacking forces and weight transfer distribution. Higher = more jacking, less body roll. Lower = more mechanical grip, more body roll.

Camber gain is how much camber changes per mm of suspension travel. More camber gain = more grip in corners but less on straights.