[GeorgeJ.]

Hi all, I am very impressed by the technology that has been incorporated in the i3 and the result is a vehicle with impressive driving dynamics. With all the experts on this forum I am wondering if any have center of gravity data in the i3 and perhaps how that stacks up with a 3 series BMW or some other benchmark? Thanks for in insights.

[jadnashuanh]

WIth all of the batteries and motor low in the vehicle, and the relatively light life module above, the CG on the i3 is lower than the 3-series. I haven't seen actual numbers.

[Kevin_Genius@BMWMtLaurel]

Originally Posted by jadnashuanh

WIth all of the batteries and motor low in the vehicle, and the relatively light life module above, the CG on the i3 is lower than the 3-series. I haven't seen actual numbers.

it's below the axle line, not 100% what it is though

[GeorgeJ.]

Originally Posted by Kevin_Genius@BMWMtLaurel

it's below the axle line, not 100% what it is though

Hi Kevin, When I read your reply I was pretty dismissive though it got me studying images of the drive module and components a bit more carefully. Less dismissive now however still not convinced. I doubt that the CG height is > 13" +/-. The first 5.5 inches is air (ground clearance). Pretty tough for 50% of the weight to be in that next 7" to 7.5" of the structure. That being said it does appear that almost all of the drive module is below the center line of the axle. The motors (and Rex motor in particular are above, much of the suspension, and many other drive related bits are also above. Still most of the 500 pound battery, much of the aluminum chassis (say 250), and some suspension, brakes, etc (call it 100). At that your talking 850 pounds below the CL of the axles. Well less than half the total weight.

While the CFRP lifemodule is on the order of 330 lbs (half of what it would be were it made of steel) there is still a lot of other stuff up there. The doors, trunk and front hatches, glass, all of the interior, etc. Add to that the motors, Rex, much of the suspension, etc. I would not be shocked to learn the CG height was below the tops of the tires but it would be fun to know for real how it compares with other vehicles. Further, whatever the figure is it will change fairly quickly as the high mounted seats become occupied.

[EnI]

Originally Posted by GeorgeJ.

Hi all, I am very impressed by the technology that has been incorporated in the i3 and the result is a vehicle with impressive driving dynamics. With all the experts on this forum I am wondering if any have center of gravity data in the i3 and perhaps how that stacks up with a 3 series BMW or some other benchmark? Thanks for in insights.

The center of gravity figures are public, published in official BMW press releases. So:

i3: 18.5"
3-series sedan: 20.0"
4-series coupe: 19.6"


Other cars:

Toyota FT-86 / Subaru BRZ / Scion FR-S: 18.1"
Tesla S: 17.5"
Lexus LFA: 17.7"
Porsche 911 GT3: 17.9"

[GeorgeJ.]

Originally Posted by EnI

The center of gravity figures are public, published in official BMW press releases. So:

i3: 18.5"
3-series sedan: 20.0"
4-series coupe: 19.6"


Other cars:

Toyota FT-86 / Subaru BRZ / Scion FR-S: 18.1"
Tesla S: 17.5"
Lexus LFA: 17.7"
Porsche 911 GT3: 17.9"

Another person (different forum) said he was told by the rep that "the CG at 18.5 inches. He also was very specific that it was the lowest CG of any production vehicle over 60 inches in height." Pretty incredible. In my search I also saw that number for the FT-86/Scion. The Tesla is also impressive. Thanks -

[jadnashuanh]

The Tesla has, on its largest battery pack, almost 4x the capacity of the i3's, so one would expect the CG to be low with that big hunk of stuff on the bottom of the car. It would be even lower if they used CFRP for the body.

[JasH]

i8 has lowest COG of any BMW. Anyone know what the actual figure is though, please?