Ilyam5

In many publicatons 545 that thy test has a much longer stopping distance compared to say 645 or even 530

The measurements are anywhere from 128 to 138 ft compared to 115 ft for 645 or 530

Any ideas? Run flats with poor grip?, different pads?

The Pentium Guy

Cold run flats?

kscarrol

just a guess, but what is the weight comparison? With the bigger engine in the 545 vs 530, I'm sure it weighs more. As for the 545 vs the 645, the 5 series sedan is a bigger car, again likely weighing more. I know the 545 has bigger brakes than the 530 but they are likely the same as the 645. My totally unresearched guess is that the heavier car accounts for the extra 13-23 ft of stopping distance.

JDN

This surprises me. I would not want the 545 to stop any faster. I am always worrying about the guys behind me. I assume they can't stop as fast as I can and try to save enough space for them, too, in case I have to let up to keep from being rear ended after I have mine under control. Almost had that happen in a fog once years ago. I was the only car involved in a 21-23 car pile up that had no damage. I let up and steered off the shoulder just before the car behind me slammed into the car in front of me. No anti-lock brakes in those days.

Nope, my 545 stops just fine. I don't really believe a 530 nor a 645 will do appreciably better. The 545 weighs about 275 pounds more than the 530, but the brake discs have an inch more diameter, front and rear. The 645 is a little heavier than the 545, about 30 pounds, and I'm betting the brakes are the same. Can't find it on the bmw site under technical data.

wiszmaster

That is the biggest issue with high performance cars with big brakes these days - not you, but the guy behind you.

we have an SL500 ... and with the electric "super brake" - the SL will damn near stand on its nose of you press hard enough. i constantly catch myself paying mroe attention to the car behind me than the one infront of me in an emergency sistuation.

mclc26

That is very true...Last summer I was driving behind a car that stopped short becuase the driver missed a turn. I slammed on my brakes in my (now gone)540 sport and came to a stop several feet behind that car. Two seconds later I feld an enormous impact slam me from behind. A Honda CRV slammed into me because it's brakes were horrible. I got out of my car to find that there were 2 more cars behind the CRV that also piled on to the accident - a toyota camry & a ford mustang. The damage that was done to those cars was horrible-the fronts were smashed in, bumpers fell off, etc. My 540, which absorbed the impact of all 3 cars behind me, had barely noticeable damage, aside from the left side of the rear bumper being pushed in. I must say that I definitely have to give BMW a thumbs up in the quality of construction and safety department for that one. Now if only the other car manufacturers could do the same.

wolverine

Given the larger brakes and wider footprint compensating somewhat for the higher weight, the stopping distance is a function of the godawful runflats. I'll bet with Max performance tires you shorten those distances considerably.

pennetta

Just like acceleration numbers, they don't mean much unless you test the cars at the same time, same road, same conditions. I can't imagine any deficiency in my 545's braking.