Classic cars forum & vehicle restoration.

Jim.Walker · Joined: 27 Dec 2008 Posts: 1229 Location: Chesterfield

Anyone remember these? Given away by Practical Motorist I think in days of yore.

Jim.
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peter scott · Joined: 18 Dec 2007 Posts: 7119 Location: Edinburgh

Hi Jim,

What an interesting device! Presumably you stick it on your side window. Have you ever checked it against a Tapley meter to see what Good, Average and Below Average amount to?

Peter
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1939 SS Jaguar 2 1/2 litre saloon

ukdave2002 · Joined: 23 Nov 2007 Posts: 4105 Location: South Cheshire

Yep

My dad had one, I seem to remember it was clear plastic, yours may have yellowed with age?

Dave

Jim.Walker · Joined: 27 Dec 2008 Posts: 1229 Location: Chesterfield

peter scott · Joined: 18 Dec 2007 Posts: 7119 Location: Edinburgh

Measuring with my highly accurate protractor I make:

Below Average = 0.292 g
Average = 0.485g
Good = 0.574g

Give or take the odd thousanth of a g.

Peter Very Happy

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1939 SS Jaguar 2 1/2 litre saloon

Penman · Joined: 23 Nov 2007 Posts: 4759 Location: Swindon, Wilts.

Hi Peter
That is interesting because using the u,v,t,s,a constant acceleration equations from school physics, the braking distance for 60mph in the HC translates to about 0.67 G and I get the same result from 30mph.
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peter scott · Joined: 18 Dec 2007 Posts: 7119 Location: Edinburgh

I can't remember but weren't the old Tapley meter MOT limits something like 0.7g for the foot brake and 0.2g for the handbrake?

Peter
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1939 SS Jaguar 2 1/2 litre saloon

Churchill Johnson · Joined: 11 Jan 2011 Posts: 359 Location: Rayleigh Essex

I can remember when i was an mot tester early 1970's being told by the instructor who was testing me that the Rover 75 and suchlike could be passed on the handbrake even though they were below the 25% of most make's of car's as they were only designed to hold the car on a hill and most certainly i could never get the rear wheel's to lock up on these.

Jim.Walker · Joined: 27 Dec 2008 Posts: 1229 Location: Chesterfield

47Jag · Posted: Fri Feb 22, 2013 1:27 am Post subject:

In 1961 (I think) when the first test, known as the 10 year test was announced, Practical Mechanics (edited by F J Camm......what a guy) gave the advice of using a common housebrick as a makeshift tester. You would drive the car at ??? MPH with the brick stood on end at right angle to the direction of motion and applied the handbrake. If it fell over then you had achieved the 25% retardation required. The brick would then be placed on it's side and the footbrake pressed at the same ???MPH. If it toppled then the 50% requirement was achieved. If the brick slid across the floor also then you had a pull Laughing

I made the last bit up.

Art

peter scott · Joined: 18 Dec 2007 Posts: 7119 Location: Edinburgh

Interesting test Art.

F.J. and his brother Sydney were both amazing guys.

I've never done it with a brick but did try it with a car battery once. It made a right mess on the carpet though!

Peter Wink

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1939 SS Jaguar 2 1/2 litre saloon

52classic · Joined: 02 Oct 2008 Posts: 493 Location: Cardiff.

What a lovely item! Never seen one before.

My own favourute brake tester (which was actually endorsed by Hot Car, back in the day) was the humble house brick.......

Place in the passenger footwell, on its side with the frog facing direction of travel. Application of the footbrake should tip the brick.

Stood as a soldier course with the frog toward the driver and the handbrake should tip the brick.

V8 Nutter · Joined: 27 Aug 2012 Posts: 587

Back in the 60's I spent about 8 hours setting up the brakes on a '37 Ford V8, cable operated Bendix. It scored 90% effeciency on a Tapley meter, the tester couldn't believe it, he got his back up meter, same result. The only trouble was, they needed setting up again a few weeks later

Jim.Walker · Joined: 27 Dec 2008 Posts: 1229 Location: Chesterfield

roverdriver · Posted: Sat Feb 23, 2013 10:25 am Post subject:

In the late 1950's, in the newsletter of the Veteran Car Club of Australia, there was a clever article about using a house brick as a decelerometer. It gave values braking efficiency if the deceleration caused an upright brick to fall over, if the 3" side was facing the direction of travel, then when the 4½" side facing. Next a brick lying on its side (3") and then a brick lying on its flat face (4½"). I doubt if any Veteran cars would manage to tip a brick that was in the latter position. Must see if I can find that article.
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