I think the rod presure that is measured depends largely on the shaft size (volume displacement) and the gas chamber volume. On some of the economical gas charged racing shocks, the gas chamber is so small the gas presure increases drastically under compression. On the higher end shocks the...
I think a great deal of the understeer experienced with fuel burn off is from decreacing inertia in the rear of the car. The car is balanced with a full load of fuel, so when the fuel is gone the moment of inertia is decreased and the car "tightens up".
