P, I think (based on a map that I saw recently) that TN has adopted the "CA, UT, NC program" --- check it out and please let us know. Anyway, DIY haven't been classified yet and speed limit seems the best method (TO ME). I lowered the speed of my BBS02 to 24 mpg with a 30 chainring in front and 11-17-28 in the rear since almost all of my riding on that bike is off road.