Originally Posted by
cyccommute
As for ergonomics, I'm not sure what your problem with the crank is. I don't notice any difference in feel or experience any problems using Hollowtech cranks nor do I have any problems shifting from the HTII to a "normal" crankset. I have both...although I don't have any square tapers anymore.
Do you know what Q factor and ankle clearance is?
On the other hand, installation for the home mechanic is simplified over a internal bearing BB and vastly simplified over the installation of a loose bearing BB.
The correct installation of a cartridge or external unit involves threading two into the frame using a spline socket. Why is one vastly more simple?
There is specifications and there is reality. The cups on an external bottom bracket don't need to torque to anywhere near the torque needed on a crankbolt for a square taper crankset. The cups aren't likely to walk out of the frame and just need to be a bit more than snug.
A square taper crank bolt needs to be very tight indeed to avoid the crank squirming off the spindle. Most people just make the crank bolt "snug" and then are surprised when the crank loosens and is quickly ruined. I speak from my own experience. Once I took to torquing the crank bolts to the higher end of your above torque, I quite ruining cranks.
The torque specs on all these parts exist for a reason, and anyone touring well away from home with a finger tight external BB is asking for a failure.
The torque necessary to install or remove any of these parts is a wrench as long as a crank arm. For crank bolts, that means one 8mm allen wrench and a slim 8 inch tube to slip over the end.
On the other hand, there is no way to grind flats on the drive side "lip" of a typical cartridge bottom bracket. Most of the bottom brackets I've seen don't have a "lip" on the drive side. There is nothing to grab onto. The tool to remove them fits in splines on the inside of the BB and doesn't allow for any kind of external removal.
Part of the problem with this conversation is that you don't seem to be familiar with the kinds of BBs you are adamantly arguing against. This is the most common Shimano cartridge style. Note the fixed cup "lip":
The ability to remove the crank with simple tools is only one aspect of the external bottom bracket that is appealing. The installation of one is far easier than any square taper or splined crankset. It's also easier for new mechanics to understand. There are a lot of nuances that need to be appreciated for a square taper that can lead to an expensive lesson if not followed. I've been down that road before as well as telling a lot of people a lot of bad news because they didn't understand those nuances.
Bottom line: It's a whole lot harder to screw up an external bottom bracket system.
You are mystifying something that is incredibly simple. You install external and cartridge BBs the same way - thread them into the frame and torque down with a spline socket. The rest of the installation for a square taper is to mount the crank arms and also firmly torque down the bolts. Why that seems complicated compared to the HTII procedure that involves a proprietary tensioning tool and needing to tighten the crank screws alternately so one doesn't build tension more than the other and bind on the spindle has me scratching my head.
The only thing I can really get from your descriptions is that you don't like the fact that a lot of things on bikes need real torque to be installed properly, and it sounds like you don't use enough torque to install your BB cups and probably not pedals either, and have screwed up things in the past with that policy.
The only people that are damaging crank arms are those that don't tighten their bolts and pedal spindles fully. And it would be extremely foolish to tour, race or ride a mile from home on a bike that isn't assembled per the manufacturers torque specs. That doesn't mean you must use a torque wrench, but you do need to use torque.