I have a 97 accord with a 2.2 non vtech engine and i just put new 18" rims and tires. The car seems to be getting worse gas mileage it has 180000 miles on it is something going wrong or is it the rims doing this?

 

That's normal. The rims and larger tires are much, much heavier than stock. More weight = lower MPG.

17"s are the middle ground, I've learned on the forum. OK MPG, OK Looks.

 

How much will the mpg go down? In theory, if the tires and wheels are larger shouldnt you get better mpg? I suppose thats only true in non- stop and go traffic.

 

The other thing to remember is that larger diameter tires will cause the speedometer/odometer to read low, so your apparent miles/gallon will drop.

 

i think the wheels are the same size as the stock ones. the tire shop put tires on rims according to the old tire sizes so i dont the the speedometer is off.

 

How many mpg should these new wheels effect should i loss just a few or is it like 10+ mpg?

 

i weighted my old wheels and my new wheels and the new ones are 7 pounds heavier should 7 pounds make a big different on gas mileage?

 

97 Accords did not come with 18" wheels so they are not stock size and the speedo/odo is off.

At 7 lbs each that's an additional 28 lbs the engine has too overcome not to mention the wider tire from stock. Different tires have different rolling resistance. You can get new tires in the proper size and still lose 1-2 MPG due to more rolling restance in the new tire as compared to the previous brand.

You would not lose 10+ MPG unless you were rolling on tires with 10 lbs of air in them.