Is going 55 mph really the best speed?

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Originally Posted by BEEF

looking at it strictly scientifically

I have seen graphs on aerodynamic drag that show there is a deflection point where drag increases sharply. the sharp increase is usually between 50 and 60 mph depending on the aerodynamics of the particular vehicle. I know I saw one that showed the optimum for a vehicle being 53MPH. I can't remember what vehicle was tested but I do remember it being old.

that may be where the whole 55MPH thing came from. it gives you the most speed for the least amount of drag.

there again, I may be reading way too much into the question.

When I worked in HVAC, I came across fan law which can be translated to cars. http://www.hvac-toolbox.com/fan-affi...aws-d_196.html

Aerodynamic drag and engine power needed changes exponentially with an increase in speed. That's why you can't regear a stock Yaris and go 200mph or use hypermiling techniques doing 90. (and expect anything good)

Speed kills.... fuel economy at least :)