Optimum fuel consumption cruising speed

No. The main factor is drag, which goes up much faster than the speed. Being at the torque peak on any Focus will put you far above the most economical speed. However, at quite low speeds the engine revs do matter, so there is an optimum speed, which is generally considered to be in the range of 70kph (45mph). Anything up to 90kph (55mph) will still be quite economical, but above that things get thirstier.

Agreed on the drag being a big issue - I have a 2001 SE (four-door) that makes the long trip to and from Milwaukee (from northern IL, USA) daily during the week, on a pretty open and straight stretch of road. Since it's almost all multi-lane freeway, I've gotten a pretty good feel on where the gas usage goes way up, just from watching the fuel gauge vs. mileage on the trip odometer.

I notice a slight drop at anything above 65mph, and a significant drop above 75mph. Cruising at a steady 72 will still get me over 30mpg, so I'm happy.

About 105 (about 65mph) is optimum for me. At 115 (72mph) I start noticing the difference. It seems that 110 gives me the speed to keep up to traffic and good (though not excellent!) mileage. 110 appears to be the best compromise between speed and economy for my 200-ZX3.

Ron

Thx gents, good data

rgds