Brake Wear on Autos

[mbenz76]

So, this being my first auto I got to thinking the other day whether audo cars naturally wear their brakes quicker than manual cars.

After all, you creep along with the brake on, and where I would probably have dropped a gear in a manual to slow down I simply brake in this.

Has anyone got any experience of this?

 

[LTD]

You will learn to blend off the throttle earlier in time.

 

[BlackC55]

I would estimate 15% more wear on an auto.

 

[seymansey]

Definitely more wear on an auto. There are some occasions where you dont have the feeling of engine braking so will naturally apply the brakes, even gently.

 

[mbenz76]

Thanks. I have considered using the flappy paddles to restrict the range when going down hill to get the engine braking I was always used to in the manual.

 

[BlackC55]

Then you are introducing wear in the gearbox. I would rather replace pads and discs than gearbox internals.

 

[mbenz76]

Never thought of it like that. Surely though that would mean manual boxes where dropping down on hills is the norm will suffer much heavier box wear than autos?

 

[hawk20]

I always choose autos. But brake wear is just not much of an issue. I never need new pads in under 30-35k miles.

 

[Burger]

Then you are introducing wear in the gearbox. I would rather replace pads and discs than gearbox internals.

I appreciate you're the expert in this but I'd really like to understand the detail behind your statement.

In the days of almost constantly slipping torque converters I would completely agree with you but in these days of auto clutches and effective lock up in all gears I would have thought selecting a low gear when descending hills, as you would in a manual box, to be absolutely the best driving practice and advice.

Please elaborate

Thanks,

 

[Bellow]

Steel gears in a manual. Soft clutches and brakes in an auto.

 

[cazyp]

Never thought of it like that. Surely though that would mean manual boxes where dropping down on hills is the norm will suffer much heavier box wear than autos?

Simple rule is that gears are for going and brakes are for slowing. Correct use of a manual gearbox except in extreme weather or gradient conditions would be to remain in a high gear for hill descent, brake and select the appropriate gear to continue the journey or to match descending revs if they are falling to a 'stall' area.
This maintains better car control and also signals to drivers behind your intentions.

Auto gearbox 'should' be used in a similar way. It's the standard method of training at Hendon. Using gears for braking is also a current driving test fail point.

As for wear and tear, I guess the drive train will be put under less stress in engine braking than during acceleration but will avoid unnecessary gear changes and clutch use.

 

[Ted]

This thread is becoming very interesting.
I use brakes almost as a 'last resort' - just knock the tiptronic if I'm accelerating down a hill, anticipate lights, and look well ahead.
I certainly don't doubt what has been said, but I find cazyp's comment

Auto gearbox 'should' be used in a similar way. It's the standard method of training at Hendon. Using gears for braking is also a current driving test fail point.

very interesting.

Basically, I have always felt in much more control of my car when using gears for braking - downshift into a corner, upshift (early) on the way out.

As I say - I'm not doubting what people are saying - It's just I learn something new every day.

Oh, and I put the auto box in neutral if I'm stopping for any length of time (traffic lights, queues etc)

Edit: Just been thinking further about this. Do I drive like this because I ride my bike the same way. I rarely brake on the approach to a bend unless I'm really hammering it (very rare these days). It just feels clumsy and 'not natural'.

 

[gkerr4]

ted - I know what you are saying - I also ride my bike like that, change down in advance of the corner - not wanting to be fiddling for a gear mid-bend - but then I always drove my (manual, to date) cars like that too.

The world has changed with regard to advice on using engine braking - indeed it seems that it is no longer 'acceptable' to do as cazyp points out. Maybe its because braking systems are much better than they used to bei'm not sure - the advice these days is to stay in the high gear and select lower gears to come out of the corner.

I don't know... - in a manual car you can't beat an early change down - hearing the engine revs pick up (a blip of the throttle in between changes of course) as you enter the corner in a, ahem, 'spirited' drive.

and likewise on a tough descent - an alpine pass for example - i'd rather use engine braking and be comfortable that my brake fluid isn't boiling over when i most need it!!

 

[whitenemesis]

I think the advice is still to use engine braking to assist on long descents to avoid over heating the brakes. Even mentions it in my owner's handbook and IIRC MB have programmed such action into various onboard systems (Distronic etc..)

 

[whitenemesis]

On my many taxi rides around Stuttgart, a quite hilly place, the drivers all nudge the selector left when approaching bends / junctions so the 'box changes down as soon as the revs allow. Leads to a bit of ESP action in the snow though!!

 

[crockers]

I've noticed with mine that when going down steep hills etc the gearbox tends to do its own engine braking.

Also I sometimes use the speedlimiter when going down steep hills.....

 

[whitenemesis]

+1 ^

Speedlimiter and Cruise both will down shift to try and maintain the set speed.

 

[Burger]

Simple rule is that gears are for going and brakes are for slowing. Correct use of a manual gearbox except in extreme weather or gradient conditions would be to remain in a high gear for hill descent, brake and select the appropriate gear to continue the journey or to match descending revs if they are falling to a 'stall' area.
This maintains better car control and also signals to drivers behind your intentions.

Auto gearbox 'should' be used in a similar way. It's the standard method of training at Hendon. Using gears for braking is also a current driving test fail point.

As for wear and tear, I guess the drive train will be put under less stress in engine braking than during acceleration but will avoid unnecessary gear changes and clutch use.

Let's not get this out of context. The suggestion/question was about manually shifting the auto box to a low gear when descending steep hills to allow engine braking to assist. I don't think anyone is seriously suggesting engine braking in an auto as an alternative to the brakes in any other circumstance. This is what Olly replied to suggesting it would damage the box and I'd really like to understand that much better.

Part of the reason I find this difficult to understand is because the 7 speed auto, at least in my car, will all on it's own eventually select a lower gear when descending a hill at 30 or 40mph. If MB thought it was bad for the box they wouldn't have programmed it this way surely?

Typically I use the flappy paddles or shift lever in my car in just three sets of circumstances.

1. I want a fast standing start.

2. I want to overtake quickly and efficiently.

3. I'm descending a steep hill, I've used the brakes to get the speed down if need be to the speed I want and now I want a lower gear to hold that speed.

Not sure how any of this can be damaging the box. Very marginally increasing wear perhaps through using it through it's range, but damaging? I don't see how. I also believe it's the correct way to drive and using lower gears to hold constant speeds on descents is I believe exactly how non-pursuit driving is still taught at Hendon and in line with the highway code. Using brakes to hold a constant speed is presenting misleading information to anyone following you.

Regards,

 

[The Pan Man]

Brakes to slow Gears to go. Gearboxes cost a lot more than brake pads.

 

[Burger]

Brakes to slow Gears to go. Gearboxes cost a lot more than brake pads.

True, but that's not the discussion here. The discussion as far as I can tell is about holding constant speed on hill descents.

IPSGA

Regards,