[BMW335iOn18s]

I think i've figured it out.

335i comes from the factory with all-season tires with a higher treadwear rating (lower rolling resistance) where as the M235i comes with summer Pilot Super Sports unless someone goes for the all-season option. That's the only thing that makes sense to me.

[Cyberdemon]

Originally Posted by BMW335iOn18s

I think i've figured it out.

335i comes from the factory with all-season tires with a higher treadwear rating (lower rolling resistance) where as the M235i comes with summer Pilot Super Sports unless someone goes for the all-season option. That's the only thing that makes sense to me.

Tire diameter and engine tune.

Having come from a F30 335i with the factory summer RFT's, I definitely observed 1-2mpg better consistently over the ~45k I had the car for compared to my 235 on the same commute (with All seasons RFT's). The F30 has a larger rolling diameter compared to the 335. (225/45/18 vs 225/40/18) - that equates to around a 4% lower rolling diameter. That gives you an easy 1+mpg right there, combine it with the slightly more aggressive PPK tune and you've got your delta.

My daily commute sees about 24-25mpg in the 235 and saw 26-27mpg in the 335.

Edit: Lol I already gave this answer 10 posts up.

[dalrx]

With gas under $2 gallon who cares! Drive like you stole it.

[rich8566]

Originally Posted by BMW335iOn18s

Hey guys,

I know fuel consumption isn't the most pressing issue for most of us, but this question does interest me...

So i looked up the official EPA numbers for the M235i and 335i in MT..

M235i: 19/28 City/Highway
335i: 20/30 City/Highway

The M235i weighs 50 lbs less, and they have the same gear ratios and final drive according to BMW USA.

Why does the M235i consume more fuel?

My 2014 M235i actual highway mileage (extended highway use at speeds not exceeding 72MPH) is identical to the highway mileage of my prior 2011 335i. Both manual tranny models got me 30-31 highway MPG. I note that throttle tip in and throttle changes were controlled and light footed.

[BMW335iOn18s]

Originally Posted by rich8566

My 2014 M235i actual highway mileage (extended highway use at speeds not exceeding 74MPH) is identical to the highway mileage of my prior 2011 335i. Both manual tranny models got me 30-31 highway MPG. I note that throttle tip in and throttle changes were controlled and light footed.

Do you have summer tires or all seasons? I couldn't break 28 mpg on my pilot super sports, unless i set cruise control around 55-65 mph. With my new DWS06, im eager to see if it improves.

[Cyberdemon]

Originally Posted by rich8566

My 2014 M235i actual highway mileage (extended highway use at speeds not exceeding 74MPH) is identical to the highway mileage of my prior 2011 335i. Both manual tranny models got me 30-31 highway MPG. I note that throttle tip in and throttle changes were controlled and light footed.

As I mentioned earlier, tire rolling diameter impacts how many revs the engine makes to turn the wheels 1 time.

The E9x uses the same wheel size as the F2x, not the slightly taller wheel found on the F30.

Perhaps someone could throw some physics at it to prove me wrong with the calculations that the higher rotational mass of the wheel cancels out the larger rolling diameter benefit, but it seems like that's a pretty decent place to start when the rest of the driveline is virtually identical.

[rich8566]

Originally Posted by BMW335iOn18s

Do you have summer tires or all seasons? I couldn't break 28 mpg on my pilot super sports, unless i set cruise control around 55-65 mph. With my new DWS06, im eager to see if it improves.

MPSS - summer tires.

[rich8566]

Originally Posted by BMW335iOn18s

Do you have summer tires or all seasons? I couldn't break 28 mpg on my pilot super sports, unless i set cruise control around 55-65 mph. With my new DWS06, im eager to see if it improves.

I have the staggered summer MPSS tires.