12 replies to this topic

[Shooter63]

This is probably one for mab01uk/Spider as both seem to have an inexhaustible supply of original documents from back in the day.
What I need to know is what was the official stopping/braking distance from say 60-0 or something similar, I've had a poke around the net but can't find a road test from period. The only thing that popped up was the Google AI thing and that stated 140' and I'm not a massive fan of that for reliable info.

Shooter

[Spider]

Thanks for the mention here mate, but sorry, I can't readily lay my hands on that info, I'm sure Martin would have it.

[stuart bowes]

how relevant would that 'official' measurement be, anyway?

 

at what time of year, what weather, what tyres, what road surface, what brake pads, how many people in the car, any luggage? .. etc

 

were they even doing that sort of test and logging results back then?  before the days of euro ncap

Edited by stuart bowes, 03 February 2025 - 10:04 AM.

[timmy850]

Road tests used to log all sorts of data, but the ones I can find today mainly measured acceleration rather than braking. The few results I found didn't show stopping distance:

 

Cooper 997 braking 60mph to zero = 5 seconds

1275GT (twin carb) braking 100kph to zero = 4.3 seconds

 

Some test have G forces:

Cooper 997 braking 60mph to zero = 0.68G

Mk2 Cooper S braking 60mph to zero = 0.88G 

Base clubman braking 60mph to zero = 0.68G 

Clubman GT braking 60mph to zero = 0.88G

Edited by timmy850, 03 February 2025 - 10:33 AM.

[Ethel]

Different tyres & friction material would make it irrelevant today, even if it exists - If you want it for practical purposes.

 

Some sort of comparison ought to be possible from looking at brake line pressure; piston & pad area; the relative diameters of drums/discs & tyres.

 

I expect quoted stopping distances come from real world tests under controlled conditions. You could potentially conduct your own if you can find their criteria 

[mab01uk]

A 1964 Autocar test of the 1275 Cooper S has these figures below for the 'from 30mph' in neutral brake test:-

Pedal Load 25lb, Retardation 0.50g, Equiv. Distance 60ft.

Pedal Load 50lb, Retardation 0.90g, Equiv. Distance 33.5ft.

Test Conditions: Dry concrete and tarmac surfaces.

 

Extract taken below from an Autocar magazine Road Test in 1963 for the 1071 Cooper S also has some info for braking from 30mph in neutral.

Test Conditions: Wet tarmac and concrete surfaces.

 

Edited by mab01uk, 03 February 2025 - 10:54 AM.

[Ethel]

Road tests used to log all sorts of data, but the ones I can find today mainly measured acceleration rather than braking. The few results I found didn't show stopping distance:

 

Cooper 997 braking 60mph to zero = 5 seconds

1275GT (twin carb) braking 100kph to zero = 4.3 seconds

 

Some test have G forces:

Cooper 997 braking 60mph to zero = 0.68G

Mk2 Cooper S braking 60mph to zero = 0.88G 

Base clubman braking 60mph to zero = 0.68G 

Clubman GT braking 60mph to zero = 0.88G

 

That's how they did it, back in the day, with a pendulum gizmo sat on the car's floor. Still do, if you can find someone who MOTs 3 wheelers. I presume the figures are maximums & there was only a pass score, nothing model specific.

 

[mab01uk]

This article testing Mini tyres linked below may also be of interest.

 

Mini Tyre Test (Practical Classics - Dec 2006):-

https://www.theminif...6/#entry3743993

Edited by mab01uk, 03 February 2025 - 11:03 AM.

[Steam]

Rather comically a rwc (read mot for uk) tester round here used to use a specific road with a very grippy surface to do brake tests as he said nearly any car would pass on it.

[imack]

Those Tapley meters are still used today for testing modern cars if they're certain types of 4wd or have an LSD or if you're testing an old elastic band drive DAF.

[Shooter63]

This article testing Mini tyres linked below may also be of interest.
 
Mini Tyre Test (Practical Classics - Dec 2006):-
https://www.theminif...6/#entry3743993

Thanks for that very helpful, much appreciated.

Shooter

[Bobbins]

I had an MOT tester climb into my Caterham with a Tapley meter because he couldn’t do the brake test on the rollers due to the LSD …. buckle up the harness I said … no need I’ll be fine he said, just hit the brakes hard when I raise my hand he said …. followed by multiple expletives when he nearly went through the screen. Prick.

[floormanager]

Those Tapley meters are still used today for testing modern cars if they're certain types of 4wd or have an LSD or if you're testing an old elastic band drive DAF.

 

MOT on my old 4WD Audi S6 used to use the meter