Just got back home and did a quick mileage calculation based on a 2000km
trip with new BFG AT 215/70R16 tires. GPS shows odometer is now out by -8%,
whereas before it was out by +1% with 19575R14 tires at front. This agrees
with a 9% difference between tire specs. Here are the numbers, adjusted for
tires:

Avg: 27.9 MPG imperial, 10.1 liters/100km

While this is much lower than my average mileage with stock tires, it is
typical of mileage seen over similar terrain at similar speeds. Route
included as many mountain passes as possible between the coast and Montana &
back... ;-)

According to the GPS, on the return trip yesterday via the Coqihalla, my
average speed from Kamloops to Hope was 98km/h, which is much faster than I
would normally drive (up the long 6-8% grades at 70-80km/h and down them at
110-120km/h). Some more trivia - the long 6% grade south into Merritt saw a
125km/h speed in neutral.

So I suspect the larger tires won't impact mileage too much, although they
certainly do reduce my effective torque. Without the 5sp granny gear,
starting on a hill would be a bit tougher.

ps: Saw a nice brown '82 Westy Diesel in Salmon Arm (Canoe Beach) with 17"
BBS wheels. Anyone on the list?

--
Shawn Wright
'88 Westy 1.6TD