ACS wheels do tend to be quite light weight. Not sure how this effects mileage though.

But you did move up from a 16 to 17" so even with a lighter wheel, I wouldn't expect to much of a difference.

 

wslam - Do you know the exact wheel sizes of your old and new wheels? Like 205/50 16' etc? This way we can see whether the outside diameter of your wheels has changed.

 

I agree with Johan. Post both tire sizes and we can see the differences.

Keep in mind that an 18% difference in MPG doesn't necessarily translate linearly to an 18% difference in tire size. In other words, a 1% tire size difference might result in a MPG difference much higher than 1%.

 

I upgraded the wheels on my E60-545 from the stock sport 18" to a set of 19"BBS RX II's and I have no actual mileage numbers, I upgraded the wheels after about

 

My apologies, I "fat fingered" the enter key....anyway. I had the 545 for only about a week so I have no mileage numbers but I did weigh the wheels and was surprised how much lighter the BBS wheels were even though being significantly larger.

Stock wheels with tires (18")
Front: 61.8 lbs
Rear: 63.6 lbs

New 19" BBS RX II Wheels:

Front: 55 lbs,
19x9
275/30YR-19 Michelin Pilot Sport A/S

Rear: 59.6 lbs
19x10
245/35YR-19 Michelin Pilot Sport A/S


Al

 

My milage was improving from a low of 18 to now 20 and still going up as I break it in. I am 3000 miles and <2 months of time. I hope engine break-in wasn't occuring at the time of wheel changes.

 

BMWFan - Did you get runflats on those 18" wheels? If so, this would explain the drop in weight I guess because bigger wheels are almost always heavier.

 

sorry for not replying.
i will find out the tire size soon on my ACS and BMW 16in on my 540.

and fyi, the technician at the auto shop was the one who told me the BMW wheels are VERY heavy compare to the ACS 17... so the bigger does not mean heavier.

 

by default it is the bigger the heavier, unless you get some special lightweight rims. If you think about it, it makes perfectly sense since the volume of the rim increases when getting bigger ones.

 

JohanDC

I had runflats on the stock 18" wheels but I opted not to get runflats on the upgraded 19" wheels because of cost, ride qaulity and tire options. No regrets so far.