HEY Ogre, why do you say never use tar on the rear. its amazing stuff. as long as you dont cover your rim in tar its fine to use on the rear. i usually put a line of tar on the rim every other spoke. its just so that you can pedal kick without the tar holding onto your pads and even throwing you over the bars. i have also found that tar makes barely any difference when put on a rim with a grind.