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Discussion Starter #1
Ok, i thought it would be nice to clear things up about M5 brakes...

So far, my thoughts are...
Ok, M5 uses double and single pistons... but they are FLOATING caliper.
this is a big difference compared to fixed calipers found in other cars...

So, i dont think that (as many people said here) argument about the brakes being week coz of few pistons really apply... 2-piston floating calipers are just as good as 4- or 8-piston fixed.

However, materials that are used in floating calipers dissipate heat at a slower rate, so i guess that is the reason the brakes fade (apparently)
 

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Well, since we now have a brakes thread... my post from another thread...

"Why the CSL doesn't have some heavy duty brakes is beyond me. It seems that BMW's intention was for that to be a track star... Seems that it should definately have gotten the big brake treatment.

The M5 and M3... well. In their defense, what percentage of owners track these cars? Honestly. Not board members (which is a decent percentage I am sure), but overall worldwide owners. I would imagine it is a pretty small percentage. In BMW's defense, why incure the expense of big brakes for a car that won't use them that much or that hard? It would primarily just make the cars more expensive. People already complain about the cost.

I know, I know.. this explaination fails one obvious point. The same could be said about a V10 that revs to over 8k and has 500hp... but we know that a huge part of that is marketing."

BTW Val, I suspect that the materials used in floating and fixed calipers is not the issue. Since both are made of steel. However, the design of the two systems... The 2 piston floating calipers' possible ability to flex, plus the less piston surface area in a two piston (versus 4 or 6 piston) design are more likely the real issues.
 

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Sorry but I cant agree as the whole philosophy behind the M models should be that they are Motorsport oriented versions of the standard models and therefore all areas of performance should be improved which includes engine, suspension, steering, brakes etc. Instead of developing and providing better brakes, like Porsche do, they spend time on heated seats, ventilated seats, Alcantara headlining, Sunblinds, lots of different wood and leather options, TV, etc etc If not standard then why not improved brakes as an option as you can get near enough anything else.

Sorry for the rant but see BMW going down the same slippery slope as Mercedes rather than taking a leaf out of Porsches book!!!
 

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Oh I agree 100% John, I just suspect that it is part of the reason for not doing more with the brakes.

Funny, it really depends on the test/review you read on the brakes. Some say they are fine, some say they fade...

I for one am not jumping on the "the brakes suck" bandwagon yet.
 

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Most of the magazine reviewers have complained about the brakes. I guess they must be fine for daily driving but need uprating in case of heavy use, in which case there are always Brembo, AP, Stoptech etc.

I'm going to take a wait & see attitude and live with them a while before I consider upgrading (which is not cheap).
 

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After experiencing severe fade after just 2-3 laps in both my E39 M5 and my E46 M3, I am incredibly frustrated to learn once again that BMW have chosen to equip the world's best high performance sedan with inferior brakes. You can say that most owners won't track their cars, but the bottom line is that some of us do, and based on past history with the E39 and E46 M cars, it appears that the new E60 M5 will suffer from inadequate braking. Just because a car can stop from 100-0 mph in a very short amount of time once or twice in a row, does NOT in any way mean that that particular braking system is truly high performance. The signs of a world class braking system, such as the M5 deserves, is very short repeatable braking distances over a protracted length of time; i.e. like those brakes found on Porsches.
The worst thing about the whole braking issue is that for about $500/car more, (their cost I'm guessing), BMW could have and should have out-fitted the E60 M5 with brakes equivalent to Brembos, etc.
 

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BMW here has always clearly stated the cars are designed for road use and NOT track use.

So If you want to track it, No Problem, have it kitted out for track use, get some Brembo's
 

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SuperBMW said:
BMW here has always clearly stated the cars are designed for road use and NOT track use.

So If you want to track it, No Problem, have it kitted out for track use, get some Brembo's
That maybe the case for the M5 but my M3 CSL was certainly marketed for track use otherwise why would it come with semi-slick tyres? Yet the brakes are not up to track use!!
 

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JohnH said:
That maybe the case for the M5 but my M3 CSL was certainly marketed for track use otherwise why would it come with semi-slick tyres? Yet the brakes are not up to track use!!
Well most people here only drive their CSL's on the road, and Most have the semi-silcks on.

Even guys with 1.3L VW golfs run semi-slicks here on the road
 

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SuperBMW said:
Well most people here only drive their CSL's on the road, and Most have the semi-silcks on.

Even guys with 1.3L VW golfs run semi-slicks here on the road
The other point is if these cars are not meant to be used on track days why does BMW offer their M5, M3 and CSL experience on race tracks and do all the testing on the Nurburgring? I suggest you try driving the CSL on Cup tyres in a British winter if they are meant for road use. BMW advise they are not used at under 7 degree or in very wet conditions.
 

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SuperBMW,
I think that you're missing the point here: Everything else about the new M5 is leading edge; e.g. engine, gearbox, suspension, etc. BUT, once again, BMW have short-changed the performance oriented driver with a mundane brake package. Especially galling is the fact that for a small investment in effort/money, the factory could have easily installed a package resembling Brembos etc. An analogy would be a person spending $50K on high-fi components except for spending $500 on speakers.
Further as JohnH states; whether you drive your M car in a spirited fashion or just drive it to the shops, BMW actively promote these cars as being 'track' type vehicles; check out the advertising for them. 'Ultimate Driving Machines' deserve ultimate brakes.
 

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I have found that with a simple change of brake pad that the brakes on the E46 M3 are adequate for most track use. My last trip to Laguna Seca being the exception. A lot of it is track dependant. While I would like to see a better system standard I don't see it as a huge problem. Its by far the easiest piece of the performance puzzle to fix.

I suspect my gripe will be with the soft suspension and lack of front end bite.
 

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thebishman said:
SuperBMW,
I think that you're missing the point here: Everything else about the new M5 is leading edge; e.g. engine, gearbox, suspension, etc. BUT, once again, BMW have short-changed the performance oriented driver with a mundane brake package. Especially galling is the fact that for a small investment in effort/money, the factory could have easily installed a package resembling Brembos etc. An analogy would be a person spending $50K on high-fi components except for spending $500 on speakers.
Further as JohnH states; whether you drive your M car in a spirited fashion or just drive it to the shops, BMW actively promote these cars as being 'track' type vehicles; check out the advertising for them. 'Ultimate Driving Machines' deserve ultimate brakes.
I think it's quite funny what you say...
If you really believe it's easy/inexpensive to fix, why BMW keeps doing it?
I guess they are doing it on purpose... meaning, they have good reasons to choose this brake setup. Maybe you can ask them what those are and then you'll be happy or at least you can understand why... and tell them you don't agree.


Let me give you an example... The brakes on the E39 (and probably E60 also) were designed so that they could stop the car fast even with poor conditions, meaning cold brakes and car travelling lots of time at high speed, then doing emergency stop. Maybe they sacrificed the fading for this ability to have imidiate optimum response from cold pads and discs. Maybe they think this is more important. Remeber one thing, E39 sold 20k M5s. How many of those are used on the track? I doubt it reaches 1k worldwide. If for the rest of the crowd the brakes perform more than ok, and if BMW sees some advantage on this kind of brake setup, they will keep doing it.

Another thing is really the brake pads. They using semi-racing pads on the track... i know some people who went to M and complained about this and they were told to use different pads. It helped a lot...
 

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If Cadillac can put 14" 4 piston Brembo's on all four corners, I would think BMW could do the same in a car costing $35K more.

Keith
 

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They could, I am sure they have their reasons not to do it...

And brembo (or other such manufacturers) is not always better, I've seen ferraris with brembo upgrades cook their rotors with 2 laps of the ring...:nono:
Also, disc size really doesn't matter nearly as much as caliper/pad size.

M have their reasons, I am sure...
 

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António Duarte said:
Also, disc size really doesn't matter nearly as much as caliper/pad size.
Not really true. Disk size and design is the #1 factor that determins the ability of the system to dissapate heat. Excess heat is the primary cause of fade.

I have measured front rotor temps on my car of over 1000F and they have been spotted with a slight glow at the track. Larger rotors and/or better ventlation would help this. Had I been runnign stock pads I would have had no brakes for turn one, however, no one in their right mind would expect the stock pads to work at the track. What I do want is a system that keeps the temps down enough that I don't boil the brake fluid like I did a few months back at Laguna Seca.
 

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I see what you say... Maybe you should use a better fluid, racing fluid maybe, although that stuff is really expensive and sensitiveto moisture mixing. I heard something called super blue, or something like that, works wonders. Also, you are correct that bigger discs can solve the fading, but you don't get better braking just by having bigger discs, that was my point...
Take the brakes on the 911TT, they are incredible and measure "just" 322mm in diameter. Monster calipers, though!

I recognise porsche brakes you can trust everytime... all the others have good and bad stuff and you never know before you try and some might be better, some worse (both OEM and aftermarket like brembo and AP). I never heard of problems with porsche brakes, except a very high usage of pads (well, what do you want, they must use something to brake, right...) and recently some negative reviews and experiences with the ceramic brakes that are optional.
Each manufacturer has it's strong point (some don't but... they tend to go bankrupt)... BMW was never known for their brakes... maybe everybody driving an M5 should write them a letter concerning this. I bet if they get 1000 letters about brake problems they will do something, at least in future models... (maybe retrofitable...) :D
 

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António Duarte said:
I see what you say... Maybe you should use a better fluid, racing fluid maybe, although that stuff is really expensive and sensitiveto moisture mixing. I heard something called super blue, or something like that, works wonders. Also, you are correct that bigger discs can solve the fading, but you don't get better braking just by having bigger discs, that was my point...
I run Super Blue in the car. It helps a lot but its not magic. Porsche brakes are generally regarded as the best for any production car. Its not just the size but also the cooling they build into the cars to help. Porsche brakes are also nice because its so much easier to change the pads vs the BMW units.

However, keep in mind the rear weight bias also makes the Porsche brakes appear better because it allows the rears to help out rather than just keeping the back of the car from dragging on the ground. With BMWs the fronts do about 80% of the work to stop the car under hard braking so we are asking a lot more of the front units because of the heavier car and the greater percentage of the load they must take.
 
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