Quote:
Originally Posted by counterbond
which one is better?
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55mph.
Real world (and yes I have tried many times) plain and simple DRAFTING only works at 55mph, above that speed I find that the big rig varies too much in speed and the wind whips the car around too much for fuel economy to improve much. On a windy day it is better than just driving 65mph but its never better than 55mph.
Now magically drafting at 55mph makes a major difference and the amount of wind whipping the car about is almost non-existant.
The only circumstance where I have found this to be different is when the big rig has a LOW DECK trailer that almost touches the ground, then at higher speeds the car actually can track the big rig, not whip around the road and get better fuel economy, but you almost never encounter one of those on the highway.
So short answer (from years of empiracle) is 55mph is always better drafting or not than faster. Drafting affects taller vehicles like a suburban more effectively than a lower car which might actually loose FE if it whips back and forth too much. And big rigs that are taller and closer to the ground work much more affectively for drafting than a normal big rig which sometimes doesn't even help my low cars.
Cheers
Ryan