[Gbtr6]

Coming home this evening and noticed something a little odd. Goin* through corners marked 40 mph with cruise at 62. As I go through the corner, the car decelerates slightly, maybe 2–3 mph. Then goes back to set speed. Is this a stability control nanny? I was nowhere near any limits at all. Just curious how this happens as all other cars I’ve had maintained speed.

Perry

[eugene89us]

Originally Posted by Gbtr6

Coming home this evening and noticed something a little odd. Goin* through corners marked 40 mph with cruise at 62. As I go through the corner, the car decelerates slightly, maybe 2–3 mph. Then goes back to set speed. Is this a stability control nanny? I was nowhere near any limits at all. Just curious how this happens as all other cars I’ve had maintained speed.

Perry

Yes, I just experienced cruise control nanny over Christmas. I was exiting on a wide ramp that is long and not sharp at all. The ramp was merging one interstate onto another. I had cruise set at 65, and having taken ramp before, knew that slowing to recommended 45 was unnecessary. However, as I approached the sharpest part of the ramp, the car slowed from 65 down to around 57, no acceleration applied by car until I finished the turn, then the car woke up and quickly accelerated me. There was no time I felt I'd lose traction, I think the car somehow figured my turning was too sharp for speed and did not speed up the car going into the turn. I found that to be quite helpful from safety perspective.

[about94ninjas]

As far as I know, it's more of a comfort thing than a safety thing. The car slows down to make the turn a little more comfortable, instead of taking it at the set speed. Newer S-classes will do the same thing, however they tie it into the drive mode. So sport mode will keep the car at a higher speed, whereas comfort will slow the car down more.

[EvenKeel]

Originally Posted by Gbtr6

Coming home this evening and noticed something a little odd. Goin* through corners marked 40 mph with cruise at 62. As I go through the corner, the car decelerates slightly, maybe 2–3 mph. Then goes back to set speed. Is this a stability control nanny? I was nowhere near any limits at all. Just curious how this happens as all other cars I've had maintained speed.

Perry

Yes, it's the "dynamic" part of Dynamic cruise control. It uses the Yaw sensor to determine cornering speed.

Not to be confused with Active Cruise Control, which is even more advanced.

[Billfitz]

Normal. The car knows enough to slow down when taking a curve.

[HighlandPete]

Originally Posted by Gbtr6

Coming home this evening and noticed something a little odd. Goin* through corners marked 40 mph with cruise at 62. As I go through the corner, the car decelerates slightly, maybe 2–3 mph. Then goes back to set speed. Is this a stability control nanny? I was nowhere near any limits at all. Just curious how this happens as all other cars I’ve had maintained speed.

Perry

It can be due to DSC intervention, but most likely you experienced what others have stated, part of the "dynamic" control. "Lateral acceleration control", to be specific. Driving speed and yaw rate are used to compute a figure for lateral acceleration.

[chowser51]

I love the feature. It’s been on my last three cars. It works really well. I was at 77mph and hit a 45mph curve and the car slowed itself through the curve and sped back up. I was trying to show my daughter how it worked. Her car doesn’t have it.