[Dc71]

I've bought these Asanti's on Monday 20x9 245/35 Nitto, 20x10.5 275/30 Nitto and what I've noticed is that GAS has been going quickly. Talked with reps/mechanic at BMW about this, which they explained about the rev/mil is where the gas being increased. Does anyone else have this problem?

[ezaircon4jc]

Yes, more rubber on the road is more resistance is lower mpg. If the tire has more revolutions per mile that will also lower apparent mpg.

[Dc71]

Any way of fixing that?

[ezaircon4jc]

Originally Posted by Dc71

Any way of fixing that?

Narrower tires. That will also kill your handling. Just use the factory sizes and you should be close to the factory mpg estimates. Your driving style also has a large impact.

[Dc71]

Well to late to get back to factory size. May change width on the rear wheels in the future.

[ezaircon4jc]

Originally Posted by Dc71

Well to late to get back to factory size. May change width on the rear wheels in the future.

BMW's do have a 20" option. Just look for the 20" tire.

Changing the tire diameter too much from factory will also jack with your speedo and odometer.

[Dc71]

Buying another pair is an option

[HighlandPete]

Originally Posted by Dc71

Well to late to get back to factory size. May change width on the rear wheels in the future.

All tires are not equal for rolling resistance, even in the same size. Wider... just makes it more complex.

You can also lose performance with wider, likely heavier rims and tires.

[ezaircon4jc]

Originally Posted by HighlandPete

All tires are not equal for rolling resistance, even in the same size. Wider... just makes it more complex.

You can also lose performance with wider, likely heavier rims and tires.

Yup... If you want the available ultimate mpg tire, look for an "ECO" tyre. You'll lose grip, but they will last longer and due to their construction will be harder. Tyres are always a compromise.

Why worry about 1 or 2 mpg when you own a performance sedan? You're already at a disadvantage trying to push around a 4K# car with a small (although turbocharged) 4-banger. If your desire is mpg, get a diesel or 4-banger FWD appliance.