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Effect of rain and speed on the efficiency...

1362 Views 8 Replies 7 Participants Last post by  Fourdoor
This morning, we got a heavy downpour. I know already that my effective range is really reduced by more than 20% when it is raining hard. So I turned on the MPGe display to watch closely. My informal observation shows that I got very very bad MPGe <68, when driving at speeds of 35 mph and lower. The slower I get, the worse off the MPGe is on the display. When I go faster, the MPGe increased to about 90, in the heavy rain. The MPGe increased as I drove at 35 to 50 mph, then it starts to go steady from 50-60 mph and starts to go down again after 60 mph.

The MPGe pattern is dramatically different when the road is dry. The optimum speed is at 25 mph when I can get the highest possible MPGe and a bonus of 22% extra range compared to that at 55 mph.

Anyone else observed this?
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One thing to remember when driving in the rain, all that water being picked up and thrown around by your tires is energy being consumed. Since water weighs about 8lb per gallon, think about how many extra pounds a tire is lifting as you drive on wet roads.

At a certain (lower) RPM your tires will be lifting the maximum amount for the maximum diameter of the wheel, at higher RPM they are going to sling that water off faster and generally not "lift" as much as far.
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