Safe Speed Forums

Another reason why you souldn't rely on This is what happened when a yummy mummy dropping someone else's kids off up our road left her Range Rover in 'P' with the handbrake off and her own daughter in the passenger seat. Daughter pushed it into 'N', it rolled down the hill and...



If Mrs Theboy's Polo hadn't been there, it could have rolled a lot further and done more damage, esp. to the little girl. The mummy offered to pay for it with the classic line "I suppose in a way it was my fault."
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On the subject of handbrakes & rear discs, the handbrake on Mk1 MX5s applies the rear disc brakes. I know this because we had to have the calipers replaced twice on ours when the thread where the cable attaches wore out, a "known weakness" on a mainly bombproof car.

no brake pedal interlock on getting out of park ??

I had a mate once who, as a student, used to show his auto into "park" as a means of doing a handbrake turn . I was amazd how long his transmission lasted whislt doing this "party piece" and it was actually a half shaft that eventually snapped rather than the pawl mechanism inside the box!

Yes, handbrakes are the "emergency brake" and need to achieve a minimum decel during type approval. They have a minimum efficiency to meet in the MOT test. That said, some cars are really awful in this respect.

Drum-in-disc handbrakes are (I think) the best solution on cars with rear discs, but not as common as you'd think because they're expensive. Ed might have a better feel than me for the number of cars using ordinary mechanical actuators on the pads, certainly my car and my wife's have the simpler setup.

Not sure why it's "bleedin' obvious" that one should leave it in first if parked up-hill and reverse if parked down hill??? Often, on many cars, reverse is the lowest gear but there can be very little in it. I tend to use reverse when facing either up OR down hill because of this.

Surely, on a car with dual circuit main braking system. the "hand brake" is provided only for parking. ISTR that it needs to hold the vehicle on a 25% hill.



My Uncle used to tell a story about having to drive up Sutton Bank in reverse in, I think, his Austin 7 because first gear was too high to manage the gradient.

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When I see an adult on a bicycle, I do not despair for the future of the human race. H.G. Wells
When I see a youth in a motor car I do d.c.brown

It needs to be able to hold the fully laden car facing up or down hill on an 18% gradient with no more than 400N applied to the handbrake lever. If you have a pedal operated handbrake, you can go up to 500N (which, I think, is why they're popular on very heavy cars). If the car can tow, it needs to hold a car and unbraked trailer laden to Gross Train Weight on a 12% gradient.

For stopping, it needs to be able to manage a deceleration of 1.5ms^-2

I agree that it's a bit pointless with dual circuit brakes but I think this requirement predated the requirement for dual circuit brakes and I guess they're reluctant to remove requirements that are already in existance. The same Directive that quotes those numbers above also sets out requirements for the main braking system and for each half of the dual circuit system.

....and only from 30kph - 0kph !