Auto-hold (brakes), did they make it worse?

[veemacks]

As a repeat offender in terms of buying Mercedes, the auto-hold always bugged me - that once you came to a complete stop, you had to give the brake pedal a bit of an extra push to turn on the auto-hold.

Then I switched to a 2019 X3, and as you came to a complete stop, the auto-hold just kicked in by itself. What a marvel of modern technology I thought. Well done BMW.

But .... my wife got a new 2023 116i last year. Her auto-hold is of the type that requires that extra push once stopped to engage it.

So my question is ... am I enjoying the luxury of auto-auto-hold because an X3 is greater than a 1 series, or is it that BMW in their infinite wisdom decided to take a step backwards in the auto-hold evolution and make it need an extra push in the newer cars?

[zx10guy]

Haven't experienced BMW's implementation of the auto brake hold function or any other manufacturer except Toyota. With my 2019 Toyota C-HR, there is a button in the center console below the gear selector/shifter that enables/disables this auto hold feature.

When I first got the car, I thought it was pretty cool and used it all the time. Not sure what your experience is with BMW's implementation, but I stopped using it with my Toyota. Reason being, I've put a lot of miles on this car so I've spent a lot of time in the car. I do all the maintenance items on this car. I found inspecting the brakes during tire rotations that the rears pads were wearing pretty quickly. Once I stopped using the auto hold feature, the rate of increased wear has seem to gone away.

[DrVenture]

Originally Posted by zx10guy

Haven't experienced BMW's implementation of the auto brake hold function or any other manufacturer except Toyota. With my 2019 Toyota C-HR, there is a button in the center console below the gear selector/shifter that enables/disables this auto hold feature.

When I first got the car, I thought it was pretty cool and used it all the time. Not sure what your experience is with BMW's implementation, but I stopped using it with my Toyota. Reason being, I've put a lot of miles on this car so I've spent a lot of time in the car. I do all the maintenance items on this car. I found inspecting the brakes during tire rotations that the rears pads were wearing pretty quickly. Once I stopped using the auto hold feature, the rate of increased wear has seem to gone away.

Interesting observation.

The usual notion is that fronts always wear more quickly, but I have seen that is not the case on all cars. For, instance my GT500 uses them for rear traction control purposes (lol) and they were gone at about 40K. The front Brembos are less than half worn.

I have also had two Hondas, the wife had an Accord and my son a Civic, that wore out rear brakes first.

Anyhow, I am Luke warm on the auto hold feature. Sometimes I use it, sometimes I don't, depending on the car. Never on the BMW though.

[zx10guy]

Originally Posted by DrVenture

Interesting observation.

The usual notion is that fronts always wear more quickly, but I have seen that is not the case on all cars. For, instance my GT500 uses them for rear traction control purposes (lol) and they were gone at about 40K. The front Brembos are less than half worn.

I have also had two Hondas, the wife had an Accord and my son a Civic, that wore out rear brakes first.

Anyhow, I am Luke warm on the auto hold feature. Sometimes I use it, sometimes I don't, depending on the car. Never on the BMW though.

What I suspect is happening is the rear brakes are what is engaged for the auto hold feature. To disengage, you step on the accelerator pedal. I think there's a slight delay between the rear brakes disengaging in response to teh engine starting to move the car. That delay is causing some dragging that I think is wearing the rear brakes prematurely.

[DrVenture]

Originally Posted by zx10guy

What I suspect is happening is the rear brakes are what is engaged for the auto hold feature. To disengage, you step on the accelerator pedal. I think there's a slight delay between the rear brakes disengaging in response to teh engine starting to move the car. That delay is causing some dragging that I think is wearing the rear brakes prematurely.

You could be right, I understood, and was adding a few observations. Apologies if I wasn't clear.

[Wolf 335]

I really like the extra-push feature on the mercedes and defintely would not want it engaging on its own every time I stop.

I use it often.

[Littlecoupe]

Originally Posted by zx10guy

What I suspect is happening is the rear brakes are what is engaged for the auto hold feature. To disengage, you step on the accelerator pedal. I think there's a slight delay between the rear brakes disengaging in response to teh engine starting to move the car. That delay is causing some dragging that I think is wearing the rear brakes prematurely.

There definitely is a moment of drag when you press the accelerator, I can both hear and feel it when I use Auto Hold.

I'm surprised it has any significant impact on rear brake wear for that very momentary period of time as the brakes disengage. The traction control that uses brakes, especially in a RWD car, will have a significant impact on brake life, as was stated.

[zx10guy]

Originally Posted by Littlecoupe

There definitely is a moment of drag when you press the accelerator, I can both hear and feel it when I use Auto Hold.

I'm surprised it has any significant impact on rear brake wear for that very momentary period of time as the brakes disengage. The traction control that uses brakes, especially in a RWD car, will have a significant impact on brake life, as was stated.

It was my observation after about 60k miles or so. After stopping the use of auto hold, I finally replaced the rear brakes at about 110k. Car has about 147k now and the rear brakes look fine when I did the tire rotation at 145k.

[veemacks]

Originally Posted by Wolf 335

I really like the extra-push feature on the mercedes and defintely would not want it engaging on its own every time I stop.

I use it often.

There aren't too many use cases for me where I wouldn't want it to engage. If you've come to a complete stop, then it's probably for traffic lights, traffic jams, other stop-start scenarios. In any of those, I don't see a benefit of keeping your foot on the brake. It'd be much quicker to get going if the auto-hold kicks in, and your foot can return to the accelerator pedal and you get going as quickly as your reaction time is.

In scenarios where you know you're not going to come to a complete stop, you'd just get down to < 1 mph and let it roll. Auto-hold never actually stops you, it just "keeps you stopped".

Maybe I'm in the minority and BMW listened and turned off auto-auto-hold

[DrVenture]

I'm lukewarm on brake hold. I wouldn't want to condition myself to believe the car was going to stay put, then be in a car with it turned off and whoopsie.

But, there are times it is convenient, particularly in a manual car, certainly on hills.