Stopping Distance

Cubits said:
Where weight becomes a hinderance is after repeated stops.

So there are a lot of factors involved in reducing stopping distance, awesomeness being one of them, weight not.
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Hang on, weight is not a factor in stopping distances? I guess Newton was wrong about his law of momentum.

I always figured all the stuff he came up with was just a result of being concussed by falling fruit....and other "scientists" thought they'd see how far they could run with it afterwards.
 
scathing said:
Hang on, weight is not a factor in stopping distances? I guess Newton was wrong about his law of momentum.

I always figured all the stuff he came up with was just a result of being concussed by falling fruit....and other "scientists" thought they'd see how far they could run with it afterwards.
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Someone must have quickly built aston martins when newton wasn't looking, because they will outstop cars far lighter (like caterhams, porsches...). They will generate more heat in the brakes and tyres though, as that extra energy has to go somewhere.

Using the basic theory of friction, the harder you press something down, the more friction you generate between it and the surface it is in contact with. A heavy car can generate plenty of braking grip, and can steamroll the road better than lighter cars (for more consistent braking).

Because of load sensitivity though, the height of the CoG in relation to the wheelbase becomes very important in distributing the braking force as evenly between the front/back wheels as possible. This is why SUV's are so awful at braking, it's not because they're heavy. There is something to be said for having a massive rolling radius and relatively small wheels/brakes though...

RR is the new FF. All of the hyper economy cars are rear engined, like the Tata Nano and the new VW Lupo.
 
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Weight definitely increases stopping distance, but it also lowers it at the same time (more traction), so it's not cut and dry.
 
You just reiterated what i said, but poorly. If mass increases stopping distance, how does it decrease it? :p

It's not cut and dry, but mass is much, much less significant than other factors in stopping distance for a single stop.
 
Viper007Bond said:
Weight definitely increases stopping distance, but it also lowers it at the same time (more traction), so it's not cut and dry.
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We can see this in an old fifth Gear episode.

They had an armoured Range Rover and a normal one. Both braked at the same time, at a slower speed the heavy one stopped first at a faster speed the lighter one sttoped first.
 
Ottobon said:
excellent post, the one thing to add is that the main reason for "awesomeness" is brake bais (i.e. having all tires break traction at the same time) many cars are setup with extreme bias towards the front tires, which although sounds safer (under-steer instead of over-steer) is actually many times less safe on good road conditions because it leads to much much longer braking distances. This can work okay on front heavy FWD cars, but even with that, on crap tires or a loose surface like dirt or snow the stopping distance suffers greatly. The thing i find strangest of all is that most car companies haven't figured out how to program ABS to fix all this, it seems completely possible, yet over and over again they fail to take the time to improve such a important aspect of vehicle safety.
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They have solved the brake bias problem. Lots of cars these days can send different braking forces to individual wheels as needed (EBD).
 
EBD does not maximise available grip. The controller is told that bias should always be towards the front. EBD is about stopping a car from spinning when the brakes are applied mid-turn, not maximising the braking potential of each wheel.

Plenty of safety devices remove agility from the car, preferring you hit something head on than not at all. It's all down to how car companies/governments perceive the ability of the average driver. The average driver sucks.
 
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