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      01-11-2012, 04:51 AM   #1
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Auto Hold/Brake question

Which option, in heavy stop start traffic would cause less wear on your braking system? Auto Hold on where the park brake is constantly on and off or just normal footbrake use with the car creeping?
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      01-11-2012, 05:24 AM   #2
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In both cases you're using the brakes via the standard pedal to come to a stop. Activating and deactivating the parking brake through Auto Hold uses the system when it wouldn't otherwise be used, so I would expect more wear. That's what it's been designed to do, though. Not using it to save the parking brake for the out years doesn't work for me.
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      01-11-2012, 06:32 AM   #3
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I use auto hold as a matter of course although I do turn off the auto stop stop in traffic (bloody annoying every 30 seconds)
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      01-11-2012, 05:11 PM   #4
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If Auto Hold is activated, it will apply rear break when the car is at standstill and the Torque on the wheels is almost zero (on the positive side). It will hold the breaks for all negative torques which is a condition for stop on up hill inclined road. Breaks are immediately released the moment net torque rises above a small positive value.

I don't think Auto Hold would cause any additional wear on the breaks pads cause if we do not use Auto Hold feature, we will have to use manual breaks to avoid car moving back with negative torques. I am not sure if one should use Auto Hold during Auto Start/ Stop condition as that would unnecessarily activate rear breaks though not affecting pads but would age actuators.

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      01-11-2012, 06:20 PM   #5
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Quote:
Originally Posted by Lotus7 View Post
Stop Mode.

I always thought that you had to keep your foot on the brake pedal, and releasing it re-started the engine. If that's the case, why would you ever engage Auto-Hold?
Not if you use start/stop and auto hold together. the car breaks, applies auto hold then engine cuts out. You can sit in stationary traffic without your foot on either pedal then the engine starts and auto hold disengages when you press accelerator pedal.
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      01-11-2012, 06:27 PM   #6
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if you dont select auto hold but still use auto start stop then you do need to keep your foot on the brake and the engine then restarts as soon as you remove your foot from the pedal.
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      01-11-2012, 06:29 PM   #7
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I also do not have any experience with Auto Start/ Stop but enjoy Auto Hold as it does not allow even an inch of car to roll back on steep roads we have in the city here. One can do it without using Auto Hold by quickly moving foot from Break pedal to Gas but I am not that quick and thus enjoy Auto Hold. May be same is true for case with Auto Stop / Start with Auto Hold.

(Don't laugh, so far I used to use hand breaks to avoid car rolling back in my old car and now I enjoy Auto Hold, no need to synch Hand Breaks)

Last edited by April1; 01-11-2012 at 06:36 PM.
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      01-11-2012, 08:28 PM   #8
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Quote:
Originally Posted by Lotus7 View Post
As Nahoa stated, when using Auto-Hold the service brakes have already brought the vehicle to a full stop, so there is no additional rear pad wear. The only additional mechanical wear is in the EMF actuators (the electronically operated servos) that push on the rear of the (rear-only) brake caliper pistons and are used for Auto-Hold, HDC, anti-slip torque vectoring, Dynamic Cruise Control, and Stability Control. They are designed for constant use.

The EMF actuator duty cycle is actually monitored and if they are used too much (typically during HDC operation) a brake overheat warning is displayed.

I wonder if anyone on this Forum has ever used HDC? I know I haven't, and probably never will.
I used it once -- not because I needed to, only 'cause I wanted to mess with it. I've been looking for a snowy incline to descend, but haven't even gotten the snow so far.
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      01-11-2012, 08:30 PM   #9
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Quote:
Originally Posted by alokbhargava View Post
I also do not have any experience with Auto Start/ Stop but enjoy Auto Hold as it does not allow even an inch of car to roll back on steep roads we have in the city here. One can do it without using Auto Hold by quickly moving foot from Break pedal to Gas but I am not that quick and thus enjoy Auto Hold. May be same is true for case with Auto Stop / Start with Auto Hold.

(Don't laugh, so far I used to use hand breaks to avoid car rolling back in my old car and now I enjoy Auto Hold, no need to synch Hand Breaks)
I think it's a great feature and your city is an awesome location to use it to its fullest!
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