Sim/flightmodel/parts/tire vrt def veh
sim/flightmodel/parts/tire_x_no_deflection sim/flightmodel/parts/tire_y_no_deflection sim/flightmodel/parts/tire_z_no_deflection
These are 10-item float arrays...for the 0-9th gear. They give you the center of each wheel (well, the center of the truck I think for multi-wheel trucks but I am not 100% sure) taking into account the landing gear raise/lowering.
sim/flightmodel/parts/tire_vrt_def_veh is the "squishing" delta due to teh struts, again a 10 item array. Positive numbers mean the gear are squished more. (So it should be added to sim/flightmodel/parts/tire_y_no_deflection
since the +y axis is up, and more squish means the gear is higher up relative to the CG.