Re wheel bearings in Matco wheels.
The oil seals are bonded to the inner bearing race, and because there is
more friction between the wheel and the seal than between the race and
the axle the race turns on the axle.
We have PN 4798 spacer in stock (.0875 X .049 X 1.365) installing this
will provide adequate bearing preload and prevent the races from
turning.
Ross Connell ---- Lancair

Ross,

 

Considering just the 200/300 series Lancairs without Outback Gear:

 

I can't find that part in the Aero Craft online catalog.  Furthermore, the dimensions that you listed don't make sense. Your analysis is wrong.  The surfaces of the nut protrusions and the spacers are too small where they meet the curved part of the bearing near the axle.  A really poor design by Matco back in the old days.

 

The problem with past Matco spacers on the old fashioned 200/300 series axles is that they only put pressure on the curved part of the seal area near the axle.  That is, they were about 1/8 inch wide, about 1/8 thick and just fit over the axle.  Since they were made of aluminum, they would quickly wear from allowing the bearing to rotate, thus allowing the wheel to loosen with resulting problems.  There may be many solutions (among them, Grove wheels), but I finally took two axle washers and flat head riveted them together just outside the step in the axle.  The flat side provided enough surface area to press against the rubber bearing seal along with the proper spacing.  I also found that another axle washer was absolutely necessary for the nut side as the same problem would occur there.  With the washers in place and tightening up the axle nut so that the wheel cannot be spun by hand has eliminated all wearing by stopping the bearing from spinning and eroding both the nut and the "spacer".