I think a big thing people are forgetting here is that GM isn't known as the pinnacle of innovative design and forward thinking in the automotive industry, at all. It often works out well for us wheelers, but most everything they have done is a decade or more behind other OEMs. They do it because it's cheaper and easier.Cliffs of my rambling is designs aren't always they way they are because they are the "best", more likely they are that way do to cost, schedule and it will meet the design constraints.
I'd agree with this.With regard to load carrying at the hubs the 10.25 the Ford F-superduty D80 and everything else that used a bigger spindle than the traditional D60/70/Dodge hybrid 80/14b is gong to be your winner.
For load carrying strength in the middle;e the best axle is whichever one you add a truss to.
If you're looking to tow all that weight up a mountain fast then you want the gears with the most contact area and the biggest most widely spaced bearings holding them up. This is going to mean D80/11.5/S110, etc, etc. Unless you're doing hot-shot towing and putting on a fuckton of miles with a lot of power going through the axle the center isn't really a concern. Think of all the overloaded E-350s that go 20+yr with D60.
Whatever your application is I'm sure a trussed D70/14b/10.25/10.5 would probably hold up just fine.
These assumptions are mostly true but they tend to break down quite a bit over half a fucking century laughing::flipoff2:
I'm no 14b fanboy but nobody there is keeping it the way it is because they don't want to offend the guy who designed it with a slide rule. He's long gone. The only thing keeping it the way it is is inertia but you can already see that starting to wear off in the later iterations.
Realistically I think that they wanted the ultra-short pinion because the overall assembly was still cheaper than the HO series it was replacing and the removable support has some benefits.
I'll add though the reason I won't touch a D70 over the other two unless it's free is the older metallurgy and design coupled with the hardest set up process. I don't want to use a case spreader and I hate that the shims are under the carrier bearings. The Ford axle sets up like a big ass 8.8. It has them on the outside. It's a time saver. Except without C clips, it saves even more time over an 8.8, which is already easy enough.
Off the shelf chrom-moly axles....
We are talking about the 37 spline pinion version... So 5.13 or 5.38 gears..
40 Spline parts
There is 3 for ya, right off the top of my head... :flipoff2:
The GM fans are quick to jump me on this, but how often do the damn things break under duress in pulling trucks, etc?
There's several articles out there talking about the quality of the axle shafts being on the high end of the spectrum. Argue all you want but it's pretty easy to look at the actual use of them and decide that they aren't needed, and they're not based on 50 year old metallurgy and design processes. Visteon is known for good shit.
Sure, they're not used as much in wheelers. It's due to a lot of "14 bolt is the absolute best" mantra being repeated over the last 20 years, the same way it has been for GM parts for years and years despite it not being gospel truth.
*Not hating on 14 bolts. They are a good axle. I just also think they are overrated and the new brand Y and Z stuff is comparable, if not a tad better. Not everyone wants to cut and clearance one. Sometimes a 10.5" is the easier to find option, and cheaper to boot. Selectable lockers are just as expensive for either one. The extra bearing support isn't a commonly utilized design anymore because it's flat out unnecessary if you design it correctly. 10.5s don't take hours extra to build like people are insisting.
I'd put them in the same category personally. I like the 10.5 because it's a very well machined axle and strong as hell in factory form. You don't need to upgrade them for most uses. For flat out cheap wheeling, weld up a 10.25/10.5 and go. They are working fine with big rubber and a lot of power for a lot of guys right here on this forum and gajillion lb ft diesel brodozers everywhere.