Hello, I have a 2009 H3, Alpha. I just put on 35 in' Pro Comp m/t's and added the front leveling kit. Since adding this I have noticed a SIGNIFICANT decrease in my MPG. I realize that bigger tires = more weight = less MPG but i have gone from about 13ish in the city to just under 10. I also have a cold air intake and cat back exhaust that have both been on for a while now. I was curious if anyone could shed any insight into why my MPG has dropped so much. My first inclination was maybe there is something that i need to adjust with my internal computer.

Any feedback would be greatly appreciated.

 

Remember new member section is for saying Hi I am new here.. You should post a tech question in the appropriate area.. But when you add tires that size, they are heavier, create more drag if they have a more aggressive tread, and also when you raise the front, you take away the little aerodynamics the H3's have, it you want to call it that. Higher front end, more air goes under, equals more drag. If gas mileage is a concern go back to stock size and a more of a less aggressive tire, and lower the front back down. Or you could buy a Prius! Just joking.

 

The speedo and odo is also wrong and has to be factored in.

 

Yeah what Hunner said.. I forgot that part also. So it might not be as bad as you think