Toed out the left wheel by 2 turns, relubed the transmission, rotated the tires, & went 8.15 miles at 319mAh/mile.  

A 9.8 miler with 2.6 at 7m15s/mile at 361mAh/mile was uneventful.  Higher speeds & hills decreased efficiency more than payload.

Then, an 11.15 miler at 345mAh ended with a noisy transmission & steering that only went left.  It carried 1lb of food back.  Still efficient, at least.  The Hitec HS-311 could be at the end of its life.  Noticed when turning left, the right wheel doesn't move because the servo horn is too small.  It drags the right wheel.

Finally cut together another video from the sphere cam on it.  Disappointing to not have figured out how to do what dollar startup insta360 does & stabilize it.  Camera shake doesn't accumulate properly in euler angles.  It might require accumulating in a quaternion.