I am in the process of rebuilding the differential following a broken axle episode. The original outside bearing was destroyed in the affected wheel and so I will be putting one of the new types on the inner and putting the old style in the outer. Over the years there has been general agreement that the new bearings are of much lesser quality than the original ribbed bearings and therefore might be dangerous to use as the outside bearing. I did a 900 day search on the subject here and have not found anyone providing evidence that the new ones are substandard, just general comments agreeing with that premise.
So the question: Has anyone ever done a test to see if the new bearings are less able to provide a safe ride? And if so, how much less safe would one be using them in all four locations?
Getting originals has become very difficult, and I have never seen an NOS offered. So is even buying a used original really safer than buying the newly manufactured ones?
Therese has been many first person witnesses to failed modern solid roller pinion bearings, so it's clear they're not safe in that application. The end of the driveshaft takes a lot of bending force since it isn't supported on the other side of the pinion. The outer rear axle bearings are in a similar situation so I think there is a risk involved in using a solid roller bearing there - with no flex in the rollers the load per square inch on the end of the rollers and the corresponding axle surface might be tog high in the long run when the car is driven on rutted roads?
But the inner axle bearings may have an easier life -the Hyatts we use now has often been scavenged from donor axles sitting in that position. In the inner position the axle has some support from the other side of the bearing. If I only had access to two good Hyatts and if I couldn't afford floating outer hubs, then maybe I would experiment with solid roller repros in the inner positions - never as outer bearings. But that's just my 2 cents..
I think you should fish in the pond and see if you can come up with a good set of used Hyatts. I don't think originals are that hard to find. I would put my best bearings on the inside because they are inaccessible and outer bearings are easily changed.
I had a similar dilemma when I rebuilt my 16's diff last fall. Original outer bearings were worn beyond use while the inners were ok, with little wear.
Luckily we had a couple of t differentials at my moms acreage, my stepdad pulled the bearings out and had two good ones. So I used them instead of the new style.
If I had to use the new style I would run them as inners bearings. Better lubrication with the gear oil and less load.
The 1913 Touring that Constantine drove from Melbourne to Moscow had a 13-15 rebuilt rearend in it with the following components:
-New replacement bearings inboard only
-Used Hyatts outboard only
-Texas T replacement axles
-Fun Projects Driveshaft bearing Kit
-Ford Retrofit Ring and Pinion
-Retrofit Bronze washers (faced off before installed)
Lots of stuff fell apart on that car during the trip, but that rearend did not fail. Noteworthy is that myself, Royce Peterson, and Charlie Jenkins, collectively put 3000 miles on that rebuilt rearend before Constantine bought this car from Charlie.
There are used Hyatts in classifieds I have been selling my stash with a few thou wear for 10. each. If the sleeves are a thou over the fit is like new.