K1200LT

Careful here. Tom specifically asked about tires for a K1200LT. This heavy luxo-tourer requires a stiffer rear tire with a heavier load rating than most other bikes.

Most tires in its 160/70-17 size are rated 73V (805 lbs) but the LT needs a 79V (963 lbs) load rated tire. That alone severely limits your tire choices.

So the current choices are ME880 Bias for long mileage but limited grip (especially in the wet or on tar snakes) or BT020 Bias for good grip and good mileage.

The BT020 Radials are no longer made in the correct load rating, nor are the BT021's. The Avon Radials have also been superceded, but they never were good on the heavy LT (extremely squirmy on the rear due to soft tread/sidewalls).

There used to be a Dunlop with the correct load rating for the LT, but it had very poor wear and would often rub the swingarm.

So the best tire for Tom's original criteria (LT, good mileage and grip) is the BT020 Bias in a 160/70B-17 rear and a 120/70B-17 front.

One of the big advantages to switching to a GT was getting back to "standard" tire sizes and load ratings. I can now ride into any tire shop or dealer and find several choices already in stock. :^)

ST1100

I ride BT-020s on my ST110A and have been very happy with them.  Excellent cornering, acceleration, and braking with 10,000 miles or better life.  My style is more roll-on and roll-off than jack rabbit acceleration and stoppie braking.  Admittedly, the lighter 660 pounds of my bike may help mileage ;)
OTOH, my gear and loas are usually over 300 lbs.

YMMV
BungeeBob

LDRider is a Service Mark, owned by Joe Denton, 1996, California