virgil

My '06 530d M-sport was around $130k new on the road. I'd expect top notch equipment for price, wouldn't you? Well, I can't complain about the engine, transmission or steering, but how about the brakes?

I did my own front pads a few weeks ago - first time I've ever done this type of work. It took me 90 minutes, including machining the lip of the edge of the rotors and confirming they weren't under size. Not bad for a first attempt, I think.

My problem is this: the brake caliper looks like a dinosaur. It's almost the size of a shoe box. But most importantly, it has only one piston. That's a real surprise to me on a $130k car. My brother bought a brand new Renault Menage RS 265 for around $50k ... just 40% of the cost of my beemer. It has Bembro brakes with 6 pistons. The caliper is bright red, lightweight and flashy. It has cooling vanes cast in.

So, does a 6 piston Bembro brake caliper work any better than a single piston BMW 5 series caliper? Why would a much cheaper car have this seemingly superior equipment? Is BMW letting us down in the brake department?

Sure, the car stops well. I have no problems with the performance of the equipment supplied, but have I been supplied the right equipment?

I'm no expert. Far from it. So I'd like to hear what people who really know think about the single piston brakes on the 5 series BMWs.

Cheers

virgil

pjinca

I have thought about this question ass well, however, there are a couple of things to keep in mind. First, time and time again BMW's perform exceptionally well in braking tests done by magazines, safety agencies, and reviewers. So the performance is more than adequate for a street driven car. Second, the E60 M5 also has single piston brakes, as does the E92 M3. Maybe BMW knows something we don't?
The key to the "superior performance" of the braking kits you mention is heat, and during a normal commute you don't have the opportunity to build the heat required to make those brake kits effective. Even an F1 car barely brakes unless it's truly driven to edge.

KyleB

Nothing new here, BMW has been using single piston brake calipers for a looooooooooooooooooooong time.

pcy

Number of pistons may not be reflective of the effectiveness of the brakes. How is the performance of your car's brakes?

So, the cost of the car should reflect in the number of pistons in the brake caliper?

AchtungE60

Bigger is not always better, more pistons is not always better. Brembo is nothing to brag about either. It's all marketing, don't get caught in the trap of the constant marketing and lying that goes on. Unfortunately it is the "capitalism" machine that has molded this type of thinking.

LessIsMore

First of all, the number of pistons is not the point, its the total surface area. Having more pistons means they can be smaller and you can spread them further around the brake disc. This means that you can dissipate heat into the caliper more easily, so you are less likely to boil the fluid.

That said, it really depends on a lot of factors - swept area, hydraulic system design, master cylinder design, pad material, caliper material, etc.

One downside is, the more pistons are used, the more the weight is likely to increase. Which increases unsprung weight.

Here you go - a 2-second Google search yielded pretty informative results:
What Are the Benefits of Six Piston Calipers? | eHow.com


Are you serious with that "capitalism machine" junk? Capitalism is what has brought aftermarket brakes, and a variety of options therein, to you as the consumer. Less "capitalism" (in other words, less-free markets) would give you fewer or no options on brakes and everything else in your life. State-mandated and "approved" brakes for all, because that's what a government panel of non-enthusiast bureaucrats has determined to be all that anyone "needs".

But fortunately we have free-ish markets in the US, and so companies compete for your business by advertising - which has the awful, terrible consequence (/sarc) of meaning that consumers are responsible for just a small amount of brain functioning in evaluting choices, and taking responsibility for what we purchase and figuring out what's the best option for ourselves. Small price to pay, in my book.

And if you think capitalism has any negative consequence of "molding thinking", maybe you should do a modicum of research on state propaganda, speech stifling, and other lovely tricks employed by governments/countries that also abhored capitalism.

pjinca

LOL, this thread went off track fairly quickly

LessIsMore

I think the question was asked and answered pretty well so far.

And back on topic - I had NO idea a BMW 530d would cost anywhere near $130K anywhere. Virgil where are you located? 535i's were less than half that new.

The Renault calipers are flashier because that's what appeals to a lot of people. They have cooling vanes because they NEED them, as they probably aren't able ot disspiate heat as well as the BMW calipers. And I'm cuious how you know the caliper is lightweight - did you weigh it against the BMW caliper, or hold it in your hand?

You ask whether BMW has let us down on the brakes - guess that depends on what your looking for. If you care about brake performance, then clearly and objectively, they have not. However, if you care about flashiness and impressing layfolks with piston counts that mean potentially nothing, then maybe they have.

pjinca

I suspect he's located where import taxes are VERY high, like some parts of Asia and the middle east, which would explain the price. Back when I had my 530 a friend from Taiwan told me it would cost about the same as an M5 does here (in the US) to buy it in Taiwan. LOL, when's the last time you saw a $50k Renault?

AchtungE60

I agree! sheesh looks like someone is passionate about lying.




Anyway, sorry to offend you. I think our definition of capitalism is much different.The marketing machines and so forth. Go to school and get an education about the ENTIRE picture and you will understand what I'm talking about eventually. I get it now. 10 yrs ago I didn't understand everything. Perhaps in 10 yrs you will. Maybe 20 or 30. Perhaps you never will.
Now go protect those opium fields that you've liberated and protect those afghani drug dealers so you can get products at a good price to dump onto the people so they can end up in rehab or in jail or killing or committing other crimes. Point is, it creates jobs. Someone eventually has to pay to keep them contained and treat them "humanly" and so forth so more taxes and money. keep your prison systems full, it's profitable and keeps the system afloat. See how off track you've gone? There isn't a thing you can bring up where I will give you facts to debunk your little passionate theories. Most likely I will give up trying after the first paragraph because it's not worth my time. I am not against capitalism, I am against people making crimes against others. We probably have different view of what a crime is. I am not against democracy but let's face facts. In the U.S. there is no democracy. They lie, cheat, backbite, slander, lobby etc. to gain ground. This is not fair and it's a crime against the people. But ask me if I care, I don't get involved in worldly affairs. Have your world and when you die have your afterlife and taste of what you've earned. So you see, it all boils down to a similar scenario: you call one person a terrorist and and another calls it a freedom fighter. Can you believe a known liar? Do you even know what a lie is?

If you were educated in worldly affairs you would think "ok the price for this vehicle is that much, and the fact that he has a close relative nearby mean he must be europe" Have you ever heard of this land called europe?