is there a better one? iv been referencing that for years and your the first person to say that.... BUT who knows, maybe its irrelevant data. is it?
It assumes your top gear is 1:1, so think an old school, non-overdrive 3 spd auto or 4 spd manual. This chart doesn't work for modern vehicles since they all have OD transmissions. Plus different cars have different ideal RPM ranges. A big American V8 can comfortably cruise at 1800 RPMs all day long, but try doing that in a little import car, especially something that makes all it's power high in the RPM range like a turbo 4 cylinder, and 1800 is lugging the engine. Conversely, that same little turbo 4 cylinder import car might comfortably cruise the highway at 3500 rpms where a diesel pickup would be bouncing off the rev limiter.
The chart recommends turning 2700-2800 rpms at 65. In our trucks, something like that would get single digit gas mileage and would only be good as a tow rig or maybe a plow truck. I don't know what vehicle or engine they are basing those numbers on but it's defiantly not accurate for a full-size V8 truck.