Car goes for journey on its own - SMASH :(

Pistons moving in the bores till the compression builds the hills force can't overcome this compression to move them any further up and down so the whole thing locks (at a guess).
 
Peerzy said:
I've tested it a few times on small hills, the car rolls a tiny bit and then seems to catch and stop, I'd no idea what was making it catch and simply thought that with enough weight and force it would sheer the catch/teeth of the cog or whatever and mess up the car. I'm far from mechanical minded as I'm sure you can tell.
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When you leave a car in gear, it is the engine that is stopping it from rolling away.

The engine only really does this on the compression stroke, so it will roll until a piston is compressing.

2nd gear is generally best, as some say the compression stoke is too short a distance on the road for 1st to keep it still.
 
BigglesPiP said:
The drive train can tolerate accelerating hard up the hill, I think it will be fine sitting still.
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Going up a hill you build up the speed/torque but if the handbreak goes would the entire weight of the car and mavity just smash straight in.

I'm sure you can lift X amount of weight at the gym, but it someone just put it straight in your hand you may struggle to keep it up.

You slowly lift the weight and build up momentium where as simply having the weight put in your hand requires you to adjust to it instantly.

Just the way I saw things, obviously wrong tho.
 
Thats people, we expend energy holding up a mass, because we are so inefficient.

A car is a mechanical device, which expends no energy keeping something still. Work Done = Force x Distance applies.
 
BigglesPiP said:
2nd gear is generally best, as some say the compression stoke is too short a distance on the road for 1st to keep it still.
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Never really tested it tbh, always left it in 1st myself its saved my ass once few weeks back actually when i fitted new rear pads and hadn't had chance to run them in, came back to the car clutch in took it out of gear, car starts rolling backwards......
 
i am amazed this isn't in the highway code for safety to be honest. Driving instructors should be made to teach this as its such a simple thing that can avoid damage to the cars if the handbrake fails and even worse can stop people being injured/killed.
 
Should always leave a car in gear when parked on a hill it's simply good practice as is dipping the clutch before starting a car which I have always done since I started to drive. My RS4 and my GT3 wouldn't start without the clutch depressed either!
 
They DO teach you this in driving lessons, pick up ANY driving theory book and it'll tell you to do this.

It's not hard to check if the car in in neutral before setting off, you should always do it and you should also dip the clutch when starting the car although I don't always bother. It's common sense really, why should someone even have to tell you to do it. The mind boggles.

Anyway lesson learnt and you know how to avoid chasing your car down a hill like Mr Bean.
 
I think some people can't multi task. You can dip a clutch, check a gear stick AND turn a key at the same time...honest. I guess I have epic coordination which is why I'm ace when on my drums......though I suspect beer makes me think that.
 
Enthusiastic driving warms up the discs, you pull on the handbrake and it's tight. Discs cool down and contract just enough to loose the friction between the pads and discs so the car starts to roll.

I'd hate to imagine it if it did go through that fence!

When I did my ROSPA driving course they tell you to always pres the clutch upon starting which I do anyway. Trying to educate my woman to do the same thing is proving difficult lol.
 
Sorry mate but should have left it in gear, crazy not to!! I leave mine in gear even when parked on my (slightly) sloped drive never mind a hill like that! Sorry but serves you right!
 
I dont leave either the van or the car in gear.

I've never had one roll away.

There is a very good reason why you dont leave old diesels in gear.
 
atpbx said:
I dont leave either the van or the car in gear.

I've never had one roll away.

There is a very good reason why you dont leave old diesels in gear.
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It would have to be an completely knackered diesel parked on a 45 degree slope to be able to get the engine to start itself in 1st gear, and even then it's unlikely.

Not putting a car in gear when you park is just stupid IMO, it takes a second to do and could prevent a lot of damage.
 
MrLOL said:
there have been all sorts of reports of handbrake failures on the vectra

such that i now always leave my car in gear in case something like this happens.
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It made me really angry that Watch Dog didn't even mention that leaving a car in gear can prevent it rolling away.

As for pressing the clutch down when you start a car. I don't have a choice, my car was made in a country where litigation specialists out number manual cars. The immobiliser only lets the starter run with the clutch down.
 
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