Originally Posted by
sstorkel
I'm not clear: what parts are worn out and must be replaced? Or are you just upgrading because you want to upgrade?
In any event, my guess is that if you're using friction shifting there won't be much of a problem mixing 9- and 10-speed components. Just don't try to run a 9-speed chain if any of your parts are designed for a 10-speed drivetrain. I personally use a 9-speed trekking crank (Shimano FC-M590) with an otherwise 10-speed Ultegra drivetrain. Had to remove one of the spacers from the drive side of the crank to get the chain line to agree with the FD, but once I did that everything worked perfectly.
I, personally, wouldn't worry too much about BB longevity. I've never managed to wear one out. If you're going to be touring in very remote destinations with atrociously bad weather, then it might pay to invest in a Chris King or Phil Wood bottom bracket. Or just carry a spare BB; they don't weigh that much.
I do tour in atrociously bad weather all the time, and I have managed to hear a bit of a rub in my bottom bracket after about 7 or 8,000 miles of use. So, for $25 or whatever, getting an Ultegra BB seems like a good investment that I can carry over to a new frame (since the frame is likely the next thing to die on my bike).
I talked more with my mechanic and it looks like the 10sp chainrings will take a 9sp chain, so I think Option 1 is the path.
Half of this is replacing parts that need replacing, but half of it is upgrading. I like a bike that really runs.