Is an 80 degree stem the same as a -10 degree stem? I know for instance to get a stem thats parallel to the ground you subtract 90-73 which is a -17 degree rise. But how do you determine angle or rise when they give you (such as this case 80 degrees) stem angle? Subtract 80 from 90 degrees to give -10 or subtract 73 from 80 to give -7 degrees?
