Originally Posted by
cyccommute
Touring. It can happen. If nothing else it is easier to work on the crank with an external bearing bottom bracket. I've had to remove a crank from a bike "in the field (see 91 above). It's much easier to do with a Hollowtech II crank.
Again, in a pinch you can do it. If you have a rebuildable external crank, the bearings are fairly easy to source and you can rebuild it. You can't really do that with a internal cartridge bearing BB.
As for getting the crank "nice and straight" that shouldn't be hard. The bearing thread in a very long ways by hand and a wrench should only be needed for the final tightening. For removal, all you have to do is get the bearing broken loose to remove it. The same applies for an internal cartridge but the tool needed to break that bearing loose is much larger and heavier and can't really be MacGyvered.
"The appropriate length wrench" is the key. The torque on a Hollowtech crank is very low...about 7 ft-lb (9n-m). Breaking the bolts loose is trivial. The NDS arm then slides off and the crank comes out.
On a square taper (or splined), the torque needed to keep the arm in place is about 30 ft-lb (40 n-m) which requires much more force to break the crank free. Self extracting bolts are much more difficult to remove because you usually don't carry a 8mm wrench that is 6" to 12" long.
Perhaps you should review your own criteria. Square taper was, and is, an old technology that people are comfortable with. It isn't superior and takes much more in terms of tools and effort to work on. The Hollowtech II is simpler to work on and, frankly, has a lot less things you have to remember to use it. Most people don't actually torque their crank arm bolts and I see the results on a very regular basis. You would not believe the number of cranks I see that have been ruined because the arm came loose. That simply doesn't happen with the Hollowtech II cranks.
My criteria are parts that are both ergonomic and last, which certain schemes do better than HTII.
I just find the argument ridiculous that a tourist will find themselves in the middle of nowhere without the availability of a bike shop or home mechanic to provide the proper tool, yet they can come up with the a specialty bottom bracket. Where would that happen?
And then the most absurd idea is that you have a tool with a handle long enough to remove/install HTII cups, which have a torque rating of 305-435 in/lbs, yet you can't put that same wrench on your crank bolts that are rated at 305-391 in/lbs. Why isn't your monkey wrench able to turn an 8mm allen wrench?
The monkey wrench will put uneven forces on your HTII cups when you tighten them down. Whether that permanently deforms them or not is going to be a matter of luck because the walls are relatively thin.
If one is that large a fan of monkey wrenches, flats could be ground on the DS lip of a typical cartridge BB so it could be replaced with the one you found in the middle of nowhere. But I think you'll find that the kind of places that have replacement BBs have installation tools.
And I don't say any of that to mean that square taper is necessarily superior (except for ankle clearance and Q factor), but just that you have to take a very biased and fantastic view of field expediency to sell the idea that HTII is a practically tool free. Like square taper, you need a spline tool, a long lever and an allen wrench.