I work part time at the local honda shop to help pay for my addiction. I don't see any issue with the 90 degree stems, as for the beads test ride. If you feel a vibration at any speed just add more beads. Typically I put 2ozs in a front tire and 3ozs in a rear. One word of warning any time you check pressure or add air roll your valve stem up between 45 and 90 degrees on the tire this will prevent any beads from getting caught in the valve core and creating a slow leak