Leaving your car in gear when parked

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TheInsanity1234
Posts: 498
Joined: Fri Oct 02, 2015 8:03 pm

Re: Leaving your car in gear when parked

Postby TheInsanity1234 » Tue Mar 22, 2016 7:21 pm

fungus wrote:AIUI, a drum has a larger contact area, and therefor more friction is produced which should result in more power. But this results in more heat being produced, which has an adverse effect on braking, therefor, drums are less efficient except as hand brakes.

Nigel.

Ah, so I see...

I wonder if someone has come up with a disc brake where you've got 4 pads acting on the same disc, on opposite ends of the axle...?

WhoseGeneration
Posts: 335
Joined: Tue Sep 29, 2015 5:02 pm

Re: Leaving your car in gear when parked

Postby WhoseGeneration » Tue Mar 22, 2016 7:36 pm

fungus wrote:
AIUI, a drum has a larger contact area, and therefor more friction is produced which should result in more power. But this results in more heat being produced, which has an adverse effect on braking, therefor, drums are less efficient except as hand brakes.

Nigel.


You only have to google a bit to find this is true. Look for the drum brakes on past racing motorcycles and cars and the complexity of trying to make them perform better.
Heat dissipation is the name of the game.
Then look for the disc brakes on large aircraft.

fungus
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Joined: Sun Dec 13, 2015 5:26 pm
Location: Dorset

Re: Leaving your car in gear when parked

Postby fungus » Tue Mar 22, 2016 7:38 pm

TheInsanity1234 wrote:
fungus wrote:AIUI, a drum has a larger contact area, and therefor more friction is produced which should result in more power. But this results in more heat being produced, which has an adverse effect on braking, therefor, drums are less efficient except as hand brakes.

Nigel.

Ah, so I see...

I wonder if someone has come up with a disc brake where you've got 4 pads acting on the same disc, on opposite ends of the axle...?


IIAC, some discs have a small drum on the rear hub for the handbrake.

Nigel.

sussex2
Posts: 540
Joined: Mon Sep 28, 2015 11:43 am

Re: Leaving your car in gear when parked

Postby sussex2 » Fri Apr 08, 2016 10:23 am

michael769 wrote:
TripleS wrote:I don't know if this is a factor that actually affects many models, but I seem to recall a time when the Citroen Xantia was said to suffer from this problem.


The Xantia's had a different problem, where the handbrake operated the front disc brakes.

The problem was that if the discs were hot enough then when they cooled and contracted the brake could let go.


It happened on the Saab models that had front wheel hand brakes as well, though they were a more robust design.
The device used to confound MOT inspectors and I always reminded them as to which wheels were braked.
It was very handy though on slippery services and a pretty powerful brake.

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Bumblebee16
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Re: Leaving your car in gear when parked

Postby Bumblebee16 » Fri Apr 22, 2016 7:42 pm

Fiat Chrysler to recall 1.1m vehicles
http://www.bbc.co.uk/news/business-36117557

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jont-
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Location: Flatlands

Re: Leaving your car in gear when parked

Postby jont- » Sat Apr 23, 2016 7:16 am

Bumblebee16 wrote:Fiat Chrysler to recall 1.1m vehicles
http://www.bbc.co.uk/news/business-36117557

Sounds like another "fix" for thick americans.
"Fiat Chrysler said it would update the vehicles to automatically prevent them from moving, even if the driver fails to put the vehicle in park. The company did not say when the fix would become available to owners."

Mind you, isn't "not moving" normal state for a Fiat? :lol:

Just like the "accelerator/brake override" problem which means you can't left foot brake in most modern cars any more :evil:

Silk
Posts: 385
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Location: South Glos.

Re: Leaving your car in gear when parked

Postby Silk » Sat Apr 23, 2016 2:33 pm

jont- wrote:Just like the "accelerator/brake override" problem which means you can't left foot brake in most modern cars any more :evil:


Indeed. Most of us are quite capable of using the controls correctly without needing technology to tell us. ;-)

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Horse
Posts: 2007
Joined: Mon Sep 28, 2015 9:20 am

Re: Leaving your car in gear when parked

Postby Horse » Sat Apr 23, 2016 3:51 pm

WhoseGeneration wrote:
fungus wrote:
AIUI, a drum has a larger contact area, and therefor more friction is produced which should result in more power. But this results in more heat being produced, which has an adverse effect on braking, therefor, drums are less efficient except as hand brakes.

Nigel.


You only have to google a bit to find this is true. Look for the drum brakes on past racing motorcycles and cars and the complexity of trying to make them perform better.
Heat dissipation is the name of the game.
Then look for the disc brakes on large aircraft.


Isn't the clue in the 'drum' bit, as far as heat dissipation goes, cooling fins/air ducts or not?
My own views. For better or worse :)

TripleS
Posts: 227
Joined: Tue Sep 29, 2015 5:39 pm
Location: Briggswath

Re: Leaving your car in gear when parked

Postby TripleS » Sat Apr 23, 2016 4:49 pm

Silk wrote:
jont- wrote:Just like the "accelerator/brake override" problem which means you can't left foot brake in most modern cars any more :evil:


Indeed. Most of us are quite capable of using the controls correctly without needing technology to tell us. ;-)


Indeed, and some of us jolly well do not want technology imposing constraints on our use of the controls. :evil:

Incidentally, I don't see how technology can determine that only the right foot can be used for braking. How would that be done - a mini video camera in the footwell from which the computer system can see that the 'wrong' foot is being used for braking? :roll:

What I have heard is that some cars will not allow simultaneous use of the accelerator and brake pedals, which means that the 'heel and toe' technique can not be used. :?

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Mr Cholmondeley-Warner
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Location: Swindon

Re: Leaving your car in gear when parked

Postby Mr Cholmondeley-Warner » Sat Apr 23, 2016 4:58 pm

LFB also uses simultaneous brake and throttle, otherwise there'd be no point in it. However cars can detect it by working out which sequence the pedals are used in, so some will allow HnT without allowing LFB.
Nick


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