Are the KH/Onza hub/crankset as good as they say they are? I am going to be in the market for a new set soon, and I was wondering if I should try the KH/Onza, or just go with Qu-Ax. Your thoughts?
Definatley go with the KH/Onza over the Qu-Ax. The Qu-Ax has only 10 splines while the KH/Onza has 36 (as many as profiles). So they will be a lot stronger, plus its the best of both KH and Onza 
That’s what I was thinking. Plus, then I don’t have to get a 48 spoke rim. I’m planning on the Alex DX32.
The number of splines in a hub and the number of spokes in a wheel are not the most important features to define the strength of a hub or wheel. In fact, those two numbers by themselves are irrelevant and mean nothing.
For a wheel the quality of the wheel build and the quality of the rim are much more important than the number of spokes. A 48 spoke wheel with a crummy rim and a crummy wheel build is going to be worse than a 36 spoke wheel with a good rim and a good wheel build.
For the hub there are many more engineering factors to consider than the number of splines. You need to consider how the cranks are attached, how strong are the cranks, how is the axle secured in the hub body (will it start creaking), what kind of metal, are there any stress risers that will start a crack, what is the root diameter of the axle, how well will the hub and cranks wear, etc., etc., etc.
I’m not making any comparisons to KH/Onza or the Qu-ax. Just saying that Just pointing out that quoting useless numbers like the number of spokes or number of splines is not the right info to base a decision on.
all things equal more spokes should mean a stronger, though heavier wheel. and there’s a limit too, where the rim is full of nipples and looses a lot of strength, but that’s some huge number of spokes.
i have no direct experience with either hub/crank set, though i think the new kh/onza’s are stronger. not sure why…
This is actually wrong on two points, as John Childs hinted at. Firstly, the Profile hub uses 48 splines, and they are of a completely different shape/profile than the KH/Onza. It’s really easy to tell the difference between the two side by side. Also, the number of splines makes nearly no difference, as John Childs said. Noone is shearing the splines of QU-ax hubs, and noone is shearing the splines off Kh hubs. So if that’s the case, what’s the concern with strength of splines. All the axles are about the same diameter, so they are all of approxamately the same strength. The cranks on Profile, Onza, and Qu-Ax are all similar, and all of them should be strong enough. Seriously, let your wallet and preferences decide, since any splined hub out there should work well.
Another point about the strength of a hub interface is that the width of the axle that actually touches the crank is more important than the number of splines. A 3 spline axles with 1" of axle length to interface with the crank will be far stronger than a 48 spline interface with 1/4" of interface.