D17thgen

iTrader: (1)

im curious about something and just wanted to know if my theory is true or false. i noticed that my overall gas mileage is reduced when im driving on wet/rain conditions compared to the clear and dry days. i was thinking that the water on the road slows down the car and requires more power (gasoline) to push it to get to whatever destination it may be. and does the climate effect the gas mileage as well? if so, how?


my second question is about tires: do tires wear more on wet roads due to the fact that when it rains, it doesnt grip as much. from what i heard (maybe just a rumor), the more grip the tire has, the more likely it doesnt have a high rating thread wear.

gearbox

iTrader: (95)

thats doubtful for the tires. when it rains usually the humidity goes way up. that means more water and less oxygen for combustion. this could result in making less power and using more fuel, since the ecu cannot detect water vapor.

Jrfish007

iTrader: (3)

Gearbox is right, but there are quite a few things that change in the rain. The most common gas killer in the rain is that people generally turn on the defroster, wich kicks the A/C compressor on, which is a big killer of gas. The fact that the tire have to push through water doesn't help either. Water vapor in the engine is obviously a gas killer too, but none of these are nearly what the defroster can do to your MPG.

As for tire wear on wet roads, yes that is in theory correct, a wet road will reduce your traction by to 2/3 of what it normally is (this is just a rule of thumb, obviously some tires are better in rain than others), but that means the tire will not wear as fast because there is less friction. The people accross the street from (a big name tire company) have made tires that will outlast your car using this concept that reducing the friction will reduce the wear. The problem is that when you reduce the friction, you reduce the handling abilties as well, so while your tires will last for ever, you have to turn at 5 MPH and can't avoid children that run in the street. I personally have never really thought about it, because that would mean I would end up going places only in the rain, and that's not feasible.

gearbox

iTrader: (95)

oh yea forgot about that stupid defroster. I cant believe how much power it eats up. i only use in emergency where sometimes the fog is so thick you cant see out the back. it sucks living in a humid place because a/c is required to be able to drive safely.

dalaw

in addition to the above suggestions, i think the wiper uses quite a bit of power, and you may have your headlights on when it rains, so that uses power too. And i think all that water splashed up into your wheel and all that rain hitting your car plus driving over puddles of water would cause significant resistance too.

Supa_Fli

yeah and considering that when you move faster the more water you go through i think its safe to say that the faster you go in rain the more of a drag your putting on your car