I recently was involved in an auto accident. It was my fault I was looking
at some stupid sign by the road and I ran into the rear end of another
car. I felt really silly. I can’t help but thonk that this may not have
happened if the brakes on my car were better. I was just wondering if I
could get some advice on brake upgrades. I also had a crazy idea… is it
possible to fit my car 85 318i with the brakes from a larger bmw that
would need more braking power say a 5 or 7 series.
Have a nice day,
Sonny
85 318i
87 golf
93 vw cabriolet
86 924
December 31, 2009
brake performance
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Sonny – Tech Support <so…@Spamsucks.mercury.interpath.net> wrote:
>I recently was involved in an auto accident. It was my fault I was looking
>at some stupid sign by the road and I ran into the rear end of another
>car. I felt really silly. I can’t help but thonk that this may not have
>happened if the brakes on my car were better. I was just wondering if I
>could get some advice on brake upgrades. I also had a crazy idea… is it
>possible to fit my car 85 318i with the brakes from a larger bmw that
>would need more braking power say a 5 or 7 series.
>Have a nice day,
You could probably retrofit M series brakes… but that seems like
overkill.
The 318i brakes are pretty good to start with. Are you sure that the
failure to stop wasn’t a tire adhesion problem? (I’m eliminating
driver malfunction, obviously).
When one wishes to stop quickly without using mechanical aids (like
the rear of the car in front of you), the goal is to have the most
adhesion possible with the road surface. So slamming on the brakes
doesn’t work, because the tires start to skid, and when they do you
lose adhesion. The car simply slides. A better approach is threshold
braking, where you keep the tires right on the edge of skidding, but
not quite crossing the line. Pumping the brakes is a crude
approximation of this technique, but is better than slamming them on.
What better brakes buy you is primarily the ability to work well after
a lot of use. Brakes work by turning kinetic energy into heat. With
hard continuous use over time, the brake pads and rotors heat up to
the point where they don’t work well anymore (the cherry red brakes of
racing cars are a good example). Better brakes have better and bigger
pads and better and bigger rotors, so they can absorb and dissipate
heat better. Some rotors have holes drilled in them, which serves to
dissipate heat through air cooling. If you race the car, or drive
hard, then this becomes very important since you really don’t want
brake fade when you’re entering a hairpin turn.
What better brakes DON’T do, generally, is to grab the tires tighter.
So having "better" brakes probably wouldn’t have helped you much in
this particular situation. If the brakes were hot enough so that fade
became a problem, you wouldn’t have had time to read the road signs
anyway. Better tires probably would have helped.
There is a SLIGHT effect from having better brake lines, which is that
they don’t expand as much so you get better feel from the brakes to
the pedal, but I doubt one would notice this under normal conditions
and with the power brakes working. There is also some variation with
use of different brake pads, but this is pretty slight compared with
tire variations.
I’d suggest that you (1) investigate whether the expense of better
tires is higher than your deductible on the insurance (of course, the
car will also corner and handle better overall, generally at the price
of a harsher ride and shorter tire life) and (2) consider taking a
performance driving school to learn threshold braking (it’s tricky to
teach yourself, because most people don’t dare take the car to the
edge).
- Hide quoted text — Show quoted text -
>Sonny
>85 318i
>87 golf
>93 vw cabriolet
>86 924
Comment by admin — December 31, 2009 @ 2:29 pm