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morisani
Italy
109 Posts |
 Posted - 30/09/2010 : 12:21:50
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The PA handbrake works interdependently with the footbrake; is this the so called "racing handbrake"? Why ?
On the subject in a 1935 book (Motor Tramp by Heygate, mentioned in Mg Road Cars vol 2 p.16) there is the following description (referred to a MG Magna) I've some difficulty to understand:" with the left hand one clipped down the handbrake on approaching a cross roads or corner, went into third gear, then shifted the left foot from the clutch on to the footbrake pedal which automatically released the handbrake so that it was all a smooth restraining movement without jars or wrench back on the engine fron the faste running trasmission; and there one was ready to accelerate up as the traffic light went green".
Thanks
Francesco |
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bahnisch
Australia
674 Posts |
Posted - 01/10/2010 : 01:16:12
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| Francesco, Your question reminded me that with my PA (my first car, over 50 years ago!) a touch on the footbrake would release the handbrake ratchet (and handbrake), very handy with the car facing uphill at traffic lights, etc. I have not tried it with my M-type or F2 but must remember to do so! |
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ags
United Kingdom
275 Posts |
Posted - 01/10/2010 : 01:51:48
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Hi Francesco,
The 'racing handbrake' is usually referred to amongst us, as a 'fly off' handbrake, as this describes its operation more simply. In other words the direction of the ratchet teeth and its method of operation is reversed. I am sure that you will have found that to get your handbrake to hold on (on all our cars except standard M types) it is necessary to press the top button of the handbrake lever Down when pulling the hand brake On. To release the handbrake it is only necessary to take the tension off the ratchet by pulling the lever back slightly and then letting the lever fly into the off position. This allows your hand to return to steering wheel or gear lever much more quickly than holding down the ratchet whilst pushing the lever forward to the off position. Hence the usefulness of the design for sprint or racing starts.
An alternative method of releasing the brakes quickly is that mentioned by Heygate (I was looking up my own copy of his book to find the context of your quotation, but could not locate it quickly enough). This is to take the tension off the handbrake by depressing the footbrake. When the tension of the brake cables is relieved from the teeth of the handbrake ratchet (and this is all that keeps the handbrake on) the lever will fly forward and the brakes will be released as the footbrake is allowed to return up. (To someone standing outside the car and not watching the driver's feet this looks like magic!.) When he says, "one clipped down the handbrake", I think that he means that the driver lightly engaged the handbrake and depressed the end button on the lever and kept the car in third gear whilst slowing on the brakes.
In other words I can understand the actions which the author is describing, and I hope that I have translated them for you into the text above, but I am still not sure why he might want to do them.
I am sure that the F type which he drove had more low speed torque than my PB, but I have found that my own fastest method up to and away from traffic lights is to heel and toe (toe of the right foot on the foot brake and heel blipping the throttle whilst the left foot looks after the clutch) down through the box to second or even first for the get away from a slow speed or from a stop.
I have always thought of the interplay between hand and foot brakes as being an accidental effect of the cable system rather than an intentional feature of the design. (To show this consider that it cannot happen on cars with hydraulic foot brakes and cable hand brakes such as all later MG models.) The choice of the cable system though, was undoubtedly intentional and you can find several quotations from Cecil Kimber to show his uncomplimentary view of the reliability of hydraulic systems in the Thirties and earlier.
As another thread here has shown gear changing on our boxes is something that comes with practice and is very difficult to explain, but is a skill which delights the successful user. For example, one gear change which I still remember from about forty years ago came when I approached a roundabout too fast and got from about sixty in third down directly into first (maximum just over twenty mph) with no gear complaints whilst slowing continuously. Try doing that on a synchromesh gear box from any time before the Nineties (or even one of our own preselectors)!. (These speeds are about 100 kph down to about 33 kph, in your system.)
I however am not the most skilled user of these gear boxes. My personal champion of champions is Steve Dear, who I have seen get into reverse silently whilst still moving forward when doing a driving test. This was a long time ago, in his pre-Cracker days whilst he was still driving the blown green PB.
More technical ramblings from
Andrew Smith MMM571 |
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MaGic_GV
United Kingdom
868 Posts |
Posted - 01/10/2010 : 10:13:24
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I have a vague recollection of reading that Tim Birkin used to use the handbrake as an aid to double declutching - i.e. instead of heel and toe. On entry to the corner, pull on and lock the handbrake, change down while double de-clutching, finally releasing the handbrake when back in gear. I've never tried it myself, heel and toe is quite satisfactory when you have mastered it - though I actually find it easier to press the brake with the left side of my foot and pivot my little piggies to blip the throttle...
This from someone who hasn't done it for far too long now...
Cheers,
Graham |
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John Reid
United Kingdom
704 Posts |
Posted - 01/10/2010 : 10:29:56
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Steve Dear was also the master of the very fast "pull through" change from 1st to 2nd at unmentionable revs, no double declutching, without apparent complaint from the gears. Who needs synchromesh!? Memories of the California Cup driving tests.
John R |
Edited by - John Reid on 01/10/2010 10:30:26 |
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Foz
United Kingdom
769 Posts |
Posted - 05/10/2010 : 17:59:22
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handbrake works better than the footbrake...useful going into hairpins from top to second but needs the brakes properly adjusted or you can visit the scenery!
On cars with the hand operated adjuster you put your foot on the brake whilst taking up the slack though this only does the footbrake and not hanbrake adjustment.
Foz |
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