Tim,
Correct me if I'm wrong, but I believe the RA103RR2 would be classified as a deep groove ball bearing. Unfortunately, I couldn't find any tech data on the Timken site about the axial capacity of their ball bearing assemblies. However, another well known manufacturer, SKF, has this to say:
If deep groove ball bearings are subjected to purely axial load, this axial load should generally not exceed the value of 0,5 C0. ... Excessive axial loads can lead to a considerable reduction in bearing service life.
(source)
Using the load rating (Co) from the catalog, 2500 lbs, these bearings are theoretically good to a side load of approximately 1250 lbs.
Now the million dollar question: Is 1250 lbs of side load capability enough? That's tough, but here's a stab at it:
Assumptions:
-Full gross weight, 1800lbs
-Single wheel carrying aircraft weight at 1G (one-wheel touchdown)
-Coefficient of friction between tire and surface 0.8 (FAR 23.479)
Ideally, the wheel tire would skid sideways before the bearing exceeds its axial load capability. Without a spacer between the bearings, the entire axial load is carried by a single bearing. The maximum axial load that the tire can generate is then 1800*.8 = 1440 lbs. Under these conditions, it appears the bearing is slightly overloaded.
Commentary:
There are of course several additional factors that should be taken into consideration. The radial touchdown load should be combined with the axial load in this scenario. This further increases the overall load on the bearing. On the other hand, the axial loads applied are likely to be of short duration. These short overload periods may reduce bearing life, but the overall bearing life may still be more than adequate. Adding a spacer between the two wheel bearings should approximately double the capacity.
In short, the analysis suggests that this new bearing, as installed, may or may not be up to the task. On to the real world testing!