The other day I parked my Mini on a hill (around a 15% slope, I think), left it in first, but forgot to engage the e-brake. When I got out, it proceeded to lurch down the hill. Luckily, the wheels were turned towards the curb and that stopped it before hitting the car in front.

Is this normal? I thought the engine compression alone should be enough to keep the car from rolling and that the e-brake was a backup (or vice-versa). The clutch is good (otherwise the roll would have been a smooth one, not lurchy).

 

If the hill is steep enough, the weight of the car can turn the engine over.

Good thing you turned the wheels to the curb. I forget sometimes (wonder what else I've forgotted from driver's ed after all these years). I do tend to remember to set the parking brake, but by dad drilled that into my head.

 

It can happen... depends on how much torque it takes to turn the puny Mini engine and 2700 lbs is a lot of torque on a steep hill.

 

I al;ways use the parking brake and leave it in neutral. It's a good habit to get into.

 

It is normal. That is why you can push start a car in first gear. The engine will turn-over while in gear if pushed or on enough of a slope.
I use the parking brake and put the car in first gear.

 

Always engage the E Brake even in an automatic

 

Compression takes a lot to overcome, but the weight of a MINI on a steep hill is a large force as well. Even compression is going to bleed out as rings aren't a perfect seal.

 

Most cars will roll in this condition (it is not a mini thing).

 

I keep the car in neutral and use the handbrake. I don't like it when mechanics or service guys leave my car in first, I usually don't realize and let the clutch out after starting...

As far as gravity, I've used 3rd for gravity starts with great results.

 

It is of course a bigger problem in smaller engined cars. A corvette might not have had the same problem.

 

Safer to put it gear (along with the handbrake), and get in the habit of it for any stick shift car. Specifically, MINIs have been reported to roll away while only on the handbrake. E-brake was found to be still engaged afterwards. The speculation is that it happens when the brake is hot, and cooling loosens the grip.

 

That's why they call it a parking brake!

 

GRAVITY....

 

funny this should come up - I normally do not use the parking brake but yesterday I found myself on a fair slope

as I left it in 1st and opened the door the car rolled back an inch or so, and I felt one cylinder come up on compression and hold the crank motionless...

so I looked down the slope, about 60 feet to where the car would back out into a busy secondary road, and then looked at the wooden guardrail that would stop it if a passing motorist didn't hit it...

and then put my butt back in the driver's seat and set the brake

i suspect that the Cooper S has a wee bit less compression than comparable 4 cylinder engines that do NOT have a supercharger, and that compression is all that prevents the engine from being driven by the wheels

it's the first car of that type that I've ever owned that caused me to think twice

anyway, better safe than sorry!