Spherically averaged values of density (left), pressure (middle), and velocity (right) as a function of radius at t = 4 kyr for the 3D Sedov explosion without diffusion (top), and with isotropic diffusion (bottom). The solid lines are the result of the simulation, and the dashed line is the analytic prediction for the standard Sedov solution. The pressure is decomposed into total pressure (black), ion pressure (blue), electron pressure (red), and CR pressure (magenta). Without diffusion, the analytic solution is reproduced well. With diffusion, there are both a CR precursor and an electron precursor.