I think I bent about 30 sets of 1 piece cranks before I finally went to 3 piece... then again those were my bmx days. Dont get me wrong they work just fine for many people but its old tech and new tech is probably lighter although it is harder to work on.

>>969993
I'm not sure if the new tech is lighter because the design requires more mass, even when aluminum is used. What if they could make the one piece out of aluminum? The hard part would be making the threads tough enough, but other than that, it should work. The bearings already ride on steel pieces separate from the crank itself. One piece aluminum crank sounds the best to me.

Mostly the lack of compatibility with other pieces, in case you need to replace the BB/pedals/chainring

http://www.sheldonbrown.com/opc.html

I'm with you that one piece cranks are excellent technology that is very very usable, reliable, and serviceable. There is a reason they are called "American." On a tour around the world, they would be specd on my bike.

Here are the reasons they have been phased out:

1. weight. it's not just a question of steel versus aluminum. the whole system has a lot of extra mass. even cottered steel cranksets are lighter because each part only has to bear load in one direction.

2. modifiability. if you want to change the gearing on your American crankset, you're pretty much SOL, except with a 5 hole adapter as pictured. but that's not really how these things are meant to be used.

3. stiffness. 99% of the time, stiffness is bullshit. but lateral stiffness of chainrings is a huge factor in shifting performance. having rings attach right at the center and not be supported out by the teeth leaves them very flexy. When running but 1x, or single/fixed, flexy chainrings are bad mostly because they make your pedaling less efficient.

Are moder n cranks as cunt-like to open as the single piece?

Sure the top nuts come out easily as long as one know that the left one opens into clokwise direction, but the bearing cups are fucking tightly held in the bottom bracket shell. Really shitty operation trying to hammer them out while the bearings, the the crank and the chainring are hanging in the way.

I bent a lot of 1-piece cranks back when I rode my BMX/Cruiser around. Jumps down stairs, bigh dirt jumps, but I only weighed 135 lbs in that era.

They're shitter in practically every way. The only advantage they could possibly have is price, but when you can get a square taper set for as low as like $50 new (and next to nothing second hand) that shouldn't be a concern.

>>970137
>Are moder n cranks as cunt-like to open as the single piece?
Nope. They require some specialised tools but they're easy to work on especially the two piece ones, if you're not removing the bottom bracket you can get the crank arms off by undoing a couple bolts and then sliding the axle and drive side arm out with a few taps from a rubber mallet (or even a good kick).