kscarrol

I don't have the Active Roll Stabalization on my 545, but I know that folks who have it are very pleased with it. My questions is does it really do anything to improve the cornering ability of the car or does it just level out the lean in a turn? I mean does the system actually shift some weight to the tires on the inside of a turn, allowing a higher cornering speed than those cars without it? Sorry, maybe this question belongs in the FAQ section.

Flowerfred

Kindof hard to tell. It feels that way for sure.
It would be interesting to do some testing on identical cars with and without.

Rudy

I don't think the laws of physics are being cheated but, if you think about it, you could say they're being 'manipulated' a little.

If the car leans in a corner, there is more weight being shifted to the outside tires. If the car stays flat in a corner, the weight is more evenly distributed across all four tires. If the inner tires are 'heavier,' they can help provide more grip to prevent the car from understeering or oversteering. Basically, more grip means less slip.

The laws of physics still hold true -- there's no way to get around them but active roll does a superb job in allowing the car to corner harder without incident. You do get the feeling that you're defying the laws of physics when you push this car hard through a turn.

I read somewhere where BMW could actually program the active roll to keep the car flatter longer but decided to actually let the car lean a little bit so the driver has some feedback as to when the laws of physics will kick in and cause the car to slide.

kscarrol

Thanks for the explanation Rudy. That's what I thought, just didn't know if the leveling action of the ARS shifted enough weight back to the inside tires to allow higher cornering speeds, or if the effect was more cosmetic for the driver and passengers. As I had indicated in an earlier thread, I really wish the ARS had been available as a standalone option when I got my car. In retrospect, that's the one thing I really wish I had on my car...

Oh yeah, and sorry about the "defying physics" sub-title. I knew the ARS wasn't defying physics, just thought it was a bit more eye catching for responses.

zag

This what i know reading some write up on ARS.
The ARS in a nutshell corrects a 9 deg roll to 4 deg. You only get a 4 deg roll on sport and stiff suspension such as those in the M cars.
As matter of fact, the e60 M5 doesn't have the ARS and active steering to maintain the sporty feel and they are effectively set up to maintain 4 deg roll at hard cornering.
So on e60 sedan, you got the ride comfort on straight cruise and reduced roll with ARS at cormering.. so it is a win win without compromise.
You can do tight slalom at high speed without much roll on the e60 equipped with ARS and Active steering. Did a comparison between this vs. 330i, at same speed the 330i was leaning left and right struggling to maintain posture while the e60 just go left and right like train on rail.

Active steering and ARS is the best thing on the e60.

just my two cents....

my530i

Totally agree with Zag's last sentence

Hormazd

Best combination of handling and ride thanks to AS

BangleBox_530d

Dynamic Drive is an active suspension control system offering an exceptionally high standard of lateral dynamic stability (body stability). This is provided by active anti-roll bars on the front and rear axles - active because rotating hydraulic elements referred to as actuators are integrated in the mechanical anti-roll bars. Incorporating two electronic pressure control valves, these actuators build up independent stability forces on the front and rear axle, minimising body sway when taking a bend

kscarrol

Thanks BangelBox, I understand how the system works, I was just hoping for either some test data or even the testimonials of folks who have driven both as to whether it really improved the cornering ability of the car. It definitely feels more stable to not have that lean when cornering, but does that translate to realworld performance or is the lack of a lean something just cosmetic so that cars with and without would lose control under similar conditions at around the same speed when cornering. Sounds like does improve the handling, or at a minimum makes the driver more confident in the car, thus "allowing" the driver to take turns faster.

John W

As I understand it, it does actually improve road-holding in turns, by increasing your contact patches on the inside wheels. By keeping the car level, the inside wheels remain flatter, and therefore maintain a larger contact patch in turns. So, it doesn't just feel like it handles better, it does handle better.

Haven't seen any stats on the two compared, though.

I has also heard what Rudy said - they had to dial it back, so it gives a little warning before breaking loose. In trials, the cars stayed so flat, you couldn't tell where the limit was. Pretty cool stuff.