Manual locking hub diameter/size?

[JoshT]

You're not telling me something I don't already know... The D35 wheel bearings are closer together than the D44's, yes. The WMS is outside of the bearing, yes. And absolutely yes there is a solution to that: Positive-offset wheels.
The factory RBV wheels had offsets of +12-19mm which puts the tire's contact patch close to right underneath the bearings (6" wide wheels had 3.75" backspacing, 7" wide wheels had 4.5" backspace).

None of that is why the D35 has an unusually-high rate of bearing failure (the D35's bearing design is actually quite robust, far more than it needed to be). Where the problem comes from is probably unexpected (I didn't make the connection myself until maybe 8-10 years ago): Aftermarket brake rotors that continue to be sold with pre-installed bearing races, but without matching cones to go with them. People (shop techs included) combine these parts on their own (often from differing countries of origin) then (not realizing why) wonder why they fail and blame it on whatever they can think of (or whatever it was they heard the last guy say, in the D35's case it's the spacing of the bearings). AFAIK, D44 wheel hubs are not sold with pre-installed races, so is why you don't see so many failed bearings on them (people are normally prompted to install both the cone and the race from a matched set since neither item pre-exists). Guaranteed if you mix races & cones on a D44, you're gonna see a similar rate of failure there too.

This is why I always tell anyone doing brake or wheel bearing work on these trucks to get rid of any pre-installed races and use both parts of a matched bearing set (perhaps the Brakes forum needs a Sticky on this). Practicing that myself, I've yet to have one fail (excepting from water intrusion once). And that's with heavy 35x12.50R15 mud tires on -12mm offset wheels (plenty of cantilever action going on there lol).

Nicely detailed diagrams, BTW

I'm not discounting your theory, really think you might be on the right track there, but...

If that is the case I have to wonder why 2WDs don't suffer the same issue. Those two come with pre installed races and get mated to existing or new bearings of a different brand/quality. Would consider that it's due to the smaller tire size, but there are plenty of them lifted up with taller tires as well.

 

[4x4junkie]

I agree, matched bearings and races as an installed pair is indeed a thing. Unfortunately, while that information is out there, it's surprising how few know about it.

Indeed.
I remember it once being common knowledge not to mix different brand (as well as new w/used) bearing cones & races, so what went awry with the brake rotor industry, I'm not sure...

I'm not discounting your theory, really think you might be on the right track there, but...


If that is the case I have to wonder why 2WDs don't suffer the same issue. Those two come with pre installed races and get mated to existing or new bearings of a different brand/quality. Would consider that it's due to the smaller tire size, but there are plenty of them lifted up with taller tires as well.

I've seen reports of it happening on 2WDs too, though you are correct in that it doesn't seem to be as often. Without having closely examined the 2WD setup I guess I don't have a good answer.
I'm gonna take a guess in that it's because it's less common for someone to put big tires on a 2wd (the ratio of 2WD trucks with big tires to ones without is lower than the ratio is for 4x4 trucks). Big tires on negative-offset wheels certainly exacerbate the issue.