Tire size & MPG

Is there a noticeable difference between 20" RFTs and the 19"s in terms of MPG? Particularly on the diesel.

I get almost 28mpg highway (MD to NJ via 95N/NJ I-295) and my daily commute is 19.4mpg which is a 8 mile round trip city drive, with a heavy foot.

20" 214's with a xDrive35d

Odometer is about 610 miles total so the engine is still breaking in a little.

I like the look of the 20"s but wondering if I'd notice the performance versus the all-seasons, especially on the diesel. I'd also save on forgoing dedicated snow tires that I'd need living in the Rockies with performance tires. 35d owners with 19" sport package happy with the handling? Any forecasts for slightly better MPG?

Originally Posted by thisispaul

I like the look of the 20"s but wondering if I'd notice the performance versus the all-seasons, especially on the diesel. I'd also save on forgoing dedicated snow tires that I'd need living in the Rockies with performance tires. 35d owners with 19" sport package happy with the handling? Any forecasts for slightly better MPG?

Once I wear out the dunlop RFT's, I plan to get non-RFT all-weathers by the winter time. I did have your concerns about handling, but it's not as big of an issue in the DC metro area...unless we get another 30" of snow like we did in March.

Also, the 20" look great, but cleaning them is a PITA. Also, you'll feel bumps in the road, so depending where you live and how well maintained your roads are will probably factor into your decision.

For me, I'll take the looks over functionality and feel for the way and where I drive.

Originally Posted by thisispaul

I like the look of the 20"s but wondering if I'd notice the performance versus the all-seasons, especially on the diesel. I'd also save on forgoing dedicated snow tires that I'd need living in the Rockies with performance tires. 35d owners with 19" sport package happy with the handling? Any forecasts for slightly better MPG?

Not to offend anyone disclaimer duly noted - I chose the sport package which arrived with extra features such as the style 335 19" rims and this was my thought process for doing so : I knew being a first time BMW owner that the ride was going to be a little more firm than what I have had in the past and while I like the looks of the 20" rims I knew there would be a drawback or two. First of all I drove a demo with the 20" and felt the difference as I knew I would and then realized that because the 20" would have a wider footprint it would bring more issues like extra splash on the rocker panels even with the flared trim, more drag which equates to MPG loss, of course higher prices to replace them, and more likely to damage the rims with potholes and such. the 20" also cost more from the dealer as well (not that bad). I really want my wife to use the X more often during her trip to our business going across a twenty four mile bridge that has the panel bumps every twenty feet or so and I knew the ride would scare her back to her Lexus I'm sure. For all those who have them I know your happy and and I think they really look sharp too but not willing to swap comfort for style this time around. Now I don't live my life by this sort of logic all the time and I can afford the rims but this time I did it this way.

Get the 20's and the BMW road hazard insurance; can't go wrong.

Originally Posted by rufnck

Get the 20's and the BMW road hazard insurance; can't go wrong.

Real good looking ride you have there.

thank you george. picked her up last friday, lots of fun

Originally Posted by thisispaul

Is there a noticeable difference between 20" RFTs and the 19"s in terms of MPG? Particularly on the diesel.

Is there a theoretical basis for this question????

If you have the same overall size, and the only difference is sidewall height, I'd say the difference is in the hundredths column...

The 20"s are fatter and stickier? No, no real theoretical basis for the question. Just curious...

Fatter tyres produce a wider front face to the air, thus your Cd factor goes up, so theoretically (in test conditions) your fuel consumption will increase.

In reality, your fuel consumption will increase because you will drive in a more "sporty"
state of mind.

Let's be honest, we buy these big 20's because they look great, for the rest they are just holes in your pocket for money to fall out of.

They wear quicker, cost more, induce more fuel consumption, and are much more prone to wheel damage as the profile is so low.
(I scragged mine duirng this past week, and didn't even know I had done it until I washed it yesterday.

20" comes with phat extended rear wheel arches, makes your X5 look so much more masculine. I parked mine next to a 50i with the 19" and reg wheel arches, the 50i looks relatively, dare I say sissy? There, I said it! Sorry. Lol.

Originally Posted by 0428

20" comes with phat extended rear wheel arches, makes your X5 look so much more masculine. I parked mine next to a 50i with the 19" and reg wheel arches, the 50i looks relatively, dare I say sissy? There, I said it! Sorry. Lol.

That is funny, I have to admit. Again, when you can afford things that make you feel good and make you happy, you have to ask yourself, why not? I'm getting too practical in my old age.