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post #20 of (permalink) Old 15-09-2006, 22:06
Scarlet Fever
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Join Date: Jul 2002
Location: Near Stansted Airport
Car: MGF
Posts: 5,476
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Hmmm, I see where you are coming from Scuzza mate.

I agree that the car can only stop within the limits of the tyres' grip on the road at any given moment and that the choice of tyres is an influential factor in this. Also, it is possible to lock the wheels up with the OE brakes, therefore they are more than capable of overcoming the tyres grip on the road. The question then is do uprated brakes make the car stop any quicker and if so how do they do this given the above?

Hmmm, from experience of the standard set up (for around 50,000 miles), the standard set up with differing pad materials (for around 30,000 miles) and my current set up, MS 4 pots, black diamond pads and 280mm discs front, OE calipers, MS discs and Mintex 1155 pads rear, brake pedal height adjuster, servo support bracket & braided hoses - there is a real, tangible reduction in stopping distances.

I have no idea why this should be the case, but i have been running 205x45 ZR 16 Marangoni Zeta Linea tyres all round for circa 60K miles and therefore have eliminated the tyre choice factor from the argument (same brand/size tyres for all of my brake spec options).

Thinking aloud...

When braking in an emergency, the idea is to bring the car to a halt in the shortest distance. This means not locking up the wheels, rather the ideal is to maintain the maximum possible brake force without loosing traction with the road surface (skidding).

Pros
Brakes that grip harder, faster will get to the 'sweet spot' where the tyres are on the verge of a skid but not quite there, quicker. This means that you are maximising the stopping potential of the tyres (particularly if you have ABS).

Cons
Brakes that grip harder, faster will make a skid more likely (unless you have ABS).

Do you follow the logic? On an ABS equipped F/TF, the quicker you can apply maximum braking force, the shorter the stopping distance. Or am i missing a trick here?

Never really thought about it before, not had the reason to try to quantify why they work, they simply do. Next time you are at the Roadsters, try to get a back to back demo in a car fitted with AP 4 pots and one without - you will be astonished.
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