You are not wrong. SRAM is simplifying things for us by adding another spindle standard to the mix...

A new BB discussion on ST is going to go off the rails quickly.

It doesn't matter what we think...SRAM can do whatever they want. Their high end groups are only sold to bike manufacturers as groups. If Giant/Specialized/Trek wants to spec 12 speed Eagle or the upcoming 12 speed E-tap with wireless braking, they have to buy the whole groupset, cranks included. They (bike manufacturers) don't care as long as it fits their frame. Bonus points if they are lighter or look more rad. SRAM can make one single crank that they believe is the best combination of weight, stiffness and longevity. They can make fewer bottom brackets. SRAM has done a lot to cut down on SKU's in recent years and when it came time to make (update) their cranks slightly more competitive with other offerings (weight, durability, stiffness), they did what they thought was best.

It makes sense to me. The only downsides of GXP was the weight and the fact that it was its own unique bearing ID on one side. It's cool how it fits every frame though. SRAM's 30mm spindle (I hesitate to call them BB30 because they called two different spindle sizes BB30) was lighter (and allegedly stiffer, whether or not a rider could tell the difference), but they claim that cramming a 30mm spindle into available bearings made for crap sealing properties and BBs going bad quickly in the mt bike world. If 1.01mm of breathing room in the ID was enough to make drastically longer lasting BB's, then great. Seeing how many of those BB's are outboard I can't make any guesses (I'm not an engineer) to the truthfulness of that. SRAM was adamant about not cramming their 30mm spindles into BB86 frames and refused to make a BB to accommodate that, so there's no comment there. I'm not sure this move to 28.99mm changes that? Those narrow BB's never made sense to me. BB90/BB86 is the main thing keeping me off a Tactical or Speed concept. I am curious how a big player like Trek will respond since they most certainly want to spec an Eagle or E-tap set.

You will have to pry my Rotor 3D+ and P2M collection out of my cold, dead hands so the road side doesn't matter to me too much. If I update my wildly outdated 2014 mt bike, maybe it will come with cool new cranks and a BB that I would never swap out anyways. Yeah, new standards every year suck, but this isn't doing anything to make our current frames or components obsolete.

Yeah it looks like this new 'standard' still leaves BB86, etc out in the cold. Personally I have an BB86 frame with a 30mm Quarq. First BB was silent for two years, second one, well, not so much.

The nice thing with the SRAM 30mm spindles is that they are long enough that you can get them in almost any frame and somewhere out there someone has made a BB to accommodate it at this point. So they're really doing the same thing, now with a 28.99mm spindle. As you said, if it magically makes all the bearings much much more durable, go for it. My question is if they can buy off the shelf bearings for all their new products or if they're all one-offs.

More products, more options.... more confusion.

I always liked the concept behind GXP where bearing loads were distributed to the NDS bearing.

My current approach is to use GXP Quarqs only and use whatever conversion BB (thread-together) is necessary for use with 30mm BB standards such as PF30, 386EVO and BBRight. No new 30mm spindled cranks for me.

Doesn't the Shimano Hollowtech II axle do the same thing?

To say it works in any frame means it’s an outboard bearing thing. It supposedly fits in every BB shell. If you try to put this in an inboard bearing application in a small diameter BB shell the bearings will be so small they’ll be useless. There are bearings like this on the market now (double row, minuscule ball size) and they will only last a few months. Even the bearing manufacturers will tell you this. They make them not because they are good but because people ask for them. I like the direction SRAM is going in. I would love to see one axle standard and a consolidation of BB shell designs.

I agree with that approach. If I were to ever put down enough power to “need” a 30mm spindle I wouldn’t bitch because, at that point, I’d be sponsored :)

If I were choosing a crank standard to save weight it wouldn’t be BB30. It would be BB386.

Not really. Hollowtech II was about increasing the bearing stance width (IIRC). GXP uses a smaller NDS bearing, a lip on the spindle, and a spring washer to actually transfer forces from the drive side to the non-drive side so that each bearing takes closer to 50% of the load (instead of 65/35 or whatever it normally is). IMO, SRAM did a really poor job of explaining the benefits of GXP in its marketing materials.

Hollowtech II and GXP bottom brackets have virtually the same width.

I always thought that SRAM did 22mm on the non-drive side simply to be different than Shimano.

Nope. The step down and the wave washer are used to transfer forces from the DS to the NDS.

That said (n=1) my GXP BBs seem to have a much shorter lifespan than my other BBs. So not sure what the real-world benefit of the clever "load transfer" is.

Whatever it is, doesn't appear significant enough for SRAM to want to keep it going forward.

GXP also seems to trash the NDS bearing first, although I usually put this down to better protection from the elements on the chainring side.
New standard does mean they no longer have to make two different axle setups, so halved the SKU's straight up.

Interestingly Shimano states that they will never manufacture the BB30 axle because of fatigue concerns of alloys.
They believe that the steel axle has far better longevity.
Now that SRAM have made it even smaller diametre, that concern should only be raised higher unless they make it heavier.
I'm interested to see what bearings they use.
I will be glad if they have improved sealing as this has always been a weak point, their BB's generally only last as well as Tiagra level stuff if ridden in the rain while Dura-ace seems indestructible in the same conditions although have much more seal drag.

I don't know about the axle proper, but I absolutely agree with Shimano on non-steel spindle threads. As a tinkerer taking off and on cranks all the time, I know from cold hard experience that you only get so many repetitions out of non-steel threads before they strip. (and that's to proper torque).

I have never stripped a thread on any crankset I have worked on.
Maybe you have a corrosion problem or the proper torque is not.