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Discussion Starter · #1 ·
Amazingly enough, these high profile vehicles still do not have roll stability control.

Acura RDX, MDX -- Lexus RX, NX -- Toyota 4Runner, Highlander -- BMW X5, X3

On the flip side, giving credit where credit is due, these SUVs do have it.

Audi Q7, Q5 -- Mercedes GLK, M-Class -- Ford Expedition, Explorer

Of course, Ford has Volvo's Roll Stability Control. :)

I read once that it was a 3-figure expense to put this in an SUV--it was fairly inexpensive. If true, what's taking everybody so long? What do you think?
 

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Of course, Ford has Volvo's Roll Stability Control. :)

I read once that it was a 3-figure expense to put this in an SUV--it was fairly inexpensive. If true, what's taking everybody so long? What do you think?
Theoretically, RSC was Ford's program. However, and perhaps for the reason you mentioned above, they never implemented it on their SUVs until after Volvo engineers took over and perfected it in the first XC90 (which was the first SUV that had a gyroscopic sensor that acted as a rollover was imminent vs. reacting once the rollover started happening).
 

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Discussion Starter · #3 · (Edited)
Theoretically, RSC was Ford's program. However, and perhaps for the reason you mentioned above, they never implemented it on their SUVs until after Volvo engineers took over and perfected it in the first XC90 (which was the first SUV that had a gyroscopic sensor that acted as a rollover was imminent vs. reacting once the rollover started happening).
Interesting. Learning is one of the reasons I post. I know that Volvo wasn't the very first with yaw-axis ESC--I think that Mercedes and BMW were?

Just looked at Wikipedia. Here's a quote.

"Ford's version of ESC, called AdvanceTrac, was launched in the year 2000. Ford later added Roll Stability Control to AdvanceTrac[14][15] which was first introduced in Volvo XC90 in 2003 when Volvo Cars was fully owned by Ford and it is now being implemented in many Ford vehicles."

Credit where credit is due. I still can't understand why so many car brands are not putting Roll Stability on their SUVs, though.

 

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BMW X5 does not have roll stability control :eek: :confused:

Where did you read this, link??
 

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Discussion Starter · #5 · (Edited)
BMW X5 does not have roll stability control :eek: :confused:

Where did you read this, link??
I. From the IIHS web site, copied and pasted from Safety Features on the BMW X5;

Side airbags: front and second row head curtain airbags and front seat-mounted torso airbags

Rollover sensor: designed to deploy the side curtain airbags in the event of an impending rollover

Driver and front passenger knee airbags: separate airbags in the lower instrument panel designed to minimize knee injuries in frontal crashes

Electronic stability control****

Antilock brakes

Programmable daytime running lights

[Notice only ESC, **** not roll stability control.]

http://www.iihs.org/iihs/ratings/vehicle/v/bmw/x5-4-door-suv

II. From the IIHS website, copied and pasted from Safety Features on the XC90;

Side airbags: head curtain airbags for all three rows of seats and front seat-mounted torso airbags

Rollover sensor: designed to deploy the side curtain airbags in the event of an impending rollover

Driver knee airbag: a separate airbag in the lower instrument panel designed to minimize knee injuries in frontal crashes

Built in child restraints (optional)

Electronic stability control, includes roll stability control *****

Antilock brakes

Daytime running lights

[Notice the Roll stability control *****addition to the ESC line]

http://www.iihs.org/iihs/ratings/vehicle/v/volvo/xc90-4-door-suv

Look at the Safety Features at the bottom of the page.
 

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So is Dynamic Stability Control (DSC) in X5 not the same??
 

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So the X5 has a rollover sensor but uses it only to deploy side airbags. Yet linking it to the ESC system would probably only be a matter of some wires and software.
 

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yea fyi, rollover protection is included in the X5 via the DSC system. Volvo's marketing acronym is rollover stability system. Aka, constant monitoring via gyroscope, and other various sensors to 1) engage brakes 2) cut torque

thats DSC from BMW. Unless some luxury carmakers decided to drop the ball and cheap out on their RD budget, rest assured that roll over control is standard. Its linked to ESP/TC systems since they use the same sensor suite.

IIHS needs to revisit their research team to fact check themselves lol
 

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yea fyi, rollover protection is included in the X5 via the DSC system. Volvo's marketing acronym is rollover stability system. Aka, constant monitoring via gyroscope, and other various sensors to 1) engage brakes 2) cut torque

thats DSC from BMW. Unless some luxury carmakers decided to drop the ball and cheap out on their RD budget, rest assured that roll over control is standard. Its linked to ESP/TC systems since they use the same sensor suite.

IIHS needs to revisit their research team to fact check themselves lol
I can't find anything about X5 rollover features on BMW websites except the sensor for the curtain bags. No mention of any interface between that sensor and DSC. Do you by any chance have a link or know what BMW calls their system?
 

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BMW's system does employ yaw sensors, as it stands today. I do not believe that is how that system worked back in 2002, when the XC90 was introduced; at that time, the RSC program was a pioneer in the automotive world.
 

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Discussion Starter · #11 · (Edited)
There's a lot of muddle on this topic, even in the automotive press. Just because you have ESC (mandatory on all cars in the US), does not mean you have Roll Stability Control. Not even all Volvos have RSC. The V60, the S60, and the S80 have ESC, but because they are low profile vehicles, they do not have RSC. ESC is stability control around the yaw axis, and RSC is stability control around the roll axis.

What amazes me is that many high profile vehicles still do not have RSC, and no, the BMW X5 and X3 do not have it.

And while many car companies have been very slow to fix their cars to "pass" the 'small overlap crash test', the slowness to put RSC on their high profile vehicles has been equally amazing.

I can't find anything about X5 rollover features on BMW websites except the sensor for the curtain bags. No mention of any interface between that sensor and DSC. Do you by any chance have a link or know what BMW calls their system?
And that's probably all you'll find with many high profile makes. The roll sensor usually just signals the side air curtains. No signal to the ABS to keep from rolling in the first place.
 

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Volvo RSC:

Bmw DSC

RSC is a programmed feature. It again uses the same sensor suite, as long as its equipped. Now if the mfg decides to just throw in the rollover protection system into the same class as ESP, ehh what can one do. A good test of any mfg system to induce roll is to find a moose avoidance maneuver test. In real time you can see how the system is engineered to handle a roll.
 

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Discussion Starter · #13 · (Edited)
Your BMW system, like the BMW video says, is around the Yaw Axis, and that's what the DSC, in the BMW video, is about. Think of the Yaw Axis as a pole from the top of the roof through the car to the pavement--it controls sideways skids. Low profile vehicles like the BMW portrayed here, don't have a tendency to roll over, so they usually don't have RSC. RSC is about the Roll Axis--think of a pole going through the front grill through the car to the back bumper. RSC counters the tendency of a high-profile vehicle to turn upside down. The upper video correctly shows that the XC60 has RSC. The XC90 has it too, but the BMW X5 and X3 do not. And yes, it would be easy for BMW to program RSC into the DSC system of the X5 and X3, which raises the question, Why not?
 

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Discussion Starter · #15 ·
Don't the XC60 and XC90 have gyroscopes that the X5 etc. do not have?
While understanding the big-picture concepts, I'm not a nuts and bolts guy. I don't know about the guts of the system--remember, I was a history major. But something about what you said sounds familiar.
 

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Discussion Starter · #17 · (Edited)
I think the Volvos do have an extra piece of hardware called a Gyrosensor, which contains a gyroscope.
Interesting. But there's no reason a high profile vehicle shouldn't have Roll Stability Control (RSC) on top of ESC.
 

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Cool video thanks!
 

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The video raises an interesting question in my mind. Often you'll hear of people upsizing and downsizing wheels/tires and the various online calculators will tell you if your actual speed is higher or lower than what the speedometer shows.

But what about calcs like ESC that are based on sensing relative wheel speeds from front to back and side to side and applying precise amount of braking or torque in order to correct it. Wouldn't changing your tire diameter (even if only by 1-2%) make these systems less effective and possibly even make them react unpredictably?

Is there a way to program tire size into the vehicle's computer and have it autocorrect for this?
 
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