I've read back through the many posts on this topic and realized this is a "cold" thread but...When I switched to OOP I went with the recommendation in Eugene Sloane's bicycling book (1980) recommending 45 deg. rather than 90 deg. The posts I've seen seem to be more toward 90 deg with a few mentioning a couple teeth, and an occasional 45 deg. Is there any consensus or has any one done a number of trials to see if there is an optimal OOP angle? I'm assuming Sloan had a reason for recommending 45 rather than 90 but he doesn't elaborate. Incidentally, I'm happy with 45 but never tried 90. Thanks. Ralph