Well, it has been raining heavily in Southern California this past week. Just drove from LA to San Diego on a fresh tank of gas. Got 47.5 mpg which is less than my usual 55 on straight highway driving.

Looks like sloshing through the rain is much harder on the engine than dry pavement. Or is it the tires?

Yes, the main problem is the extra "rolling resistance" added by the tires doing the work of sloshing the rain out of the way to get to the concrete. It seems trivial, but it's not. There is also the added weight of the rain on the car and the rain getting sloshed up under the fenderwells and under the car, which again, seems trivial but is another factor in the equation.

My HCH mileage has suffered badly anytime I have been driving in rain. I've seen drops of 3-7 MPG depending on the heaviness of the rain.

There is also the slight effect that rainy weather is USUALLY cold and possibly windy.

I did not believe this to be fact until it happened to me a few times !!!

I'm in LA too.
This morning it was raining fairly steadily.
My MPG has averaged 58 or 59 lately.
Today I got 52 MPG.

Hi All:

___The HCH’ers in this thread should consider themselves lucky … An Insight 5-speed not only has to track 2 tires through the spray, they track all 4 due to the unique aerodynamics and the way the F & R tracks were setup to minimize it. The result is a total loss of lean burn due to the much higher RR and you can easily get nailed by 25 - 35 mpg or more off a normal 105 - 110 mpg cruise

___Good Luck

___Wayne R. Gerdes
___Hunt Club Farms Landscaping Ltd.
___Waynegerdes@earthlink.net

No kidding, it seems like rain would not impede your movement much but it seems to add that little ¨push¨ that keeps nicking away at your speed, meaning you have to apply a bit more acceleration to coast.

Is that 58 to 59 in mixed commuting, or mostly highway? I am still mastering the techniques of hypermiling.

80% of my mileage is put on during my freeway commute of 17.2 miles each way on cruise control, no major hills.

The other 20% is just errands around the city, which I try to do right after work when the car is warmed up from my commute.

I drive alone and do all the hypermile things mentioned on this website except lean-burn.
I can't wrap my head around the lean burn idea.
I don't know if my HCH CVT does it.
Seems to me what gravity takes away going up a hill it gives back on the way down, within limits.
Sorry guys.
But my mileage is *smoking* without worrying about it.