"Typically the inner and outer bearings and seals are a different sizes."
not necessarily. For smaller load bearing axles the spindle can be straight, not stepped.
My axles take the 1 1/16 " bearings. #44649, inner and outer.
the seals can be a problem as I have experienced. There seems to be 2 different seals with the same outer diameter but different inner diameters because some straight spindles have a different inner step. One is 1.25" inner, and the other is 1.5" inner.....so you have to measure the old seal or get a number off the old one.
