Quote:
Originally Posted by Transfer
I would likely go for glass roof delete. I'm sure it weighs a LOT more than 57 lbs. These things can weigh 100-200 lbs all in.
|
Quote:
Originally Posted by Ibiza
It's not going to happen for the US market. The X3 M40i has option 402 as standard, which means moonroof is standard for US X3M/X4M. Due to DOT safety testing, if BMW NA has 402 standard for certification, then it can not be deleted. No way around it, unless you import a euro spec roof with 402 deleted and retro yourself.
|
A Dealer allowed me to measure a used 2016 F15’s Panorama roof – 35” x 42”, or 1470 in sq. Therefore, 103.45 lbs./1470 in sq yields 0.0703 lbs./in sq. Using that to estimate the weight of X3M’s moon roof – 0.0703 lbs./in sq x 1800 in sq =
126.6 lbs. for the X3M Moon roof. Subtracting 15 lbs. for what the Aluminum OEM part of that space is (if moon roof deleted), yields
112 lbs erased off the highest point where it yields the most benefit.
Once the weight distribution %’s are known one can roughly quantify the significance for
improving the CG and SSF (
static stability factor, equals [track width/2] divided by CG height). For my previous calculations based on Curb wt of 4317 lbs and moon roof wt of 67 lbs., the CG was lowered 1” and the SSF improved from 1.26 to a near car-like 1.32. Obviously moon roof delete of 112 lbs. will be even more significant. Loads of online sites review and discuss these terms if you search CG and SSF and desire more background on the subject.
As the US Govt and Automotive Industry have worked diligently for > 15 years to lower rollover accidents, most common in SUVs and Pick-ups, by stressing the value in lowering CG and raising SSF in vehicle design, it is incomprehensible to me that BMW wouldn’t/couldn’t get quick approval from Govt agencies on this simple request of replacing a heavy moon roof with a solid OEM aluminum version here in the US. The FDA has proven it can fast track meds which clearly show significant clinical benefit when side effect data support safety. And in this case, extensive literature and studies documenting the critical benefits of making such changes to SUVs are readily available, fully endorsed and encouraged by the NHTSA of the DOT, which actually demanded ‘Rollover resistance ratings. And there is no expense to BMW as they already have a solid roof going on X3Ms to other countries. It’s one thing for the ’18 G01 models in the US to not get the M Sport steering wheel, but this is a totally different ballgame and one that clearly impacts safety. And although a CFRP roof would have been even more helpful, it probably only removes an additional 18 lbs. over the OEM solid Al roof so hard to be dogmatic on that, even though I lobbied heavily for it and still think it should be an option for M Enthusiasts.
So if Ibiza is correct in his assertion that US X3M owners will not be able to delete the Moon Roof from our orders, a choice which would clearly improve our safety and the stability of our X3M (and thereby improve handling and cornering and surely skid pad data),
perhaps some calls to NHTSA and DOT are in order to see what they could recommend …