Perfect weight distribution

[(H)]

Perfect weight distribution. That's what BMW, that's what ///M cars in particular are known for. Man, I have so much still to learn about driving this beast. Every time I think I have exhausted the cars limits, I realize in hindsight that I have reached my limits and have to work on my skills.

Practicing some threshold breaking below. I love how the shift in weight distribution shows in this picture. And I love how awesome the car looks. Most four door sedans would look really stupid in this extreme braking position.

For some track vids, see http://f10.m5post.com/forums/showthread.php?t=1028104

Thank you, Alex Rubenstein, for the great pictures!

[shahano]

Nice pic

[bimmer-boy]

Nice picture.

Glad your enjoying your M///

[Used2be]

Originally Posted by (H)

Practicing some threshold breaking below.

The car is very poised for a heavy sedan. Is the ABS system disabled when we turn off the DSC completely? I've only done one track day so haven't explored all the possibilities with the car. If the ABS is still functional, do you mean threshold braking until you feel the ABS kick in? Or are you able to lock up the tires?

[Boss330]

Originally Posted by Used2be

The car is very poised for a heavy sedan. Is the ABS system disabled when we turn off the DSC completely? I've only done one track day so haven't explored all the possibilities with the car. If the ABS is still functional, do you mean threshold braking until you feel the ABS kick in? Or are you able to lock up the tires?

ABS is not disabled. Treshold braking is fully achieveable on a ABS car if I'm not misunderstanding how you use the term in English.

Treshold braking is to be as close to lock up as possible, without locking up. ABS only intervenes when you actually have locked up. In theory at least, you can treshold brake on a ABS equipped car by braking just on the limit and just before ABS kicks in.


To the OP:

What is perfect weight distribution?

The ideal weight distribution for a track car is not 50/50, but probably closer to 60/40 rear bias. However, for a saloon car with a traditional front engine layout, the closer you get to 50/50 the better it is. This is also what BMW put's a lot of effort into achieving and why BMW's often is reported to have better balance than a MB AMG or Audi RS (especially a Audi since they often is closer to a 60/40 front bias).

I also used to believe that BMW's claim that 50/50 was the ideal weight distribution was a objective "truth" for all cars. However I learned from others on this forum that a rear bias is better for response and turn in, as well as more rear end grip for acceleration. But since a front engine RWD car won't be able to achieve that distribution, a 50/50 is far better than a 60/40. But not as good as a 40/60...

[M6-Coupe]

Originally Posted by Used2be

The car is very poised for a heavy sedan. Is the ABS system disabled when we turn off the DSC completely? I've only done one track day so haven't explored all the possibilities with the car. If the ABS is still functional, do you mean threshold braking until you feel the ABS kick in? Or are you able to lock up the tires?

Originally Posted by Boss330

ABS is not disabled. Treshold braking is fully achieveable on a ABS car if I'm not misunderstanding how you use the term in English.

Treshold braking is to be as close to lock up as possible, without locking up. ABS only intervenes when you actually have locked up. In theory at least, you can treshold brake on a ABS equipped car by braking just on the limit and just before ABS kicks in.

^This... and also Active M differential is enable. Although DSC is disable, but still collects data from sensors and reports them to ECU to provide feedback for differential!

To the OP:

What is perfect weight distribution?

The ideal weight distribution for a track car is not 50/50, but probably closer to 60/40 rear bias. However, for a saloon car with a traditional front engine layout, the closer you get to 50/50 the better it is. This is also what BMW put's a lot of effort into achieving and why BMW's often is reported to have better balance than a MB AMG or Audi RS (especially a Audi since they often is closer to a 60/40 front bias).

I also used to believe that BMW's claim that 50/50 was the ideal weight distribution was a objective "truth" for all cars. However I learned from others on this forum that a rear bias is better for response and turn in, as well as more rear end grip for acceleration. But since a front engine RWD car won't be able to achieve that distribution, a 50/50 is far better than a 60/40. But not as good as a 40/60...

You are correct! and that's why the best handling cars like 911 have almost 60/40 (rear/front) weight distributions.

Boss, rarely I agree with you

[Palomequet]

Originally Posted by Boss330

ABS is not disabled. Treshold braking is fully achieveable on a ABS car if I'm not misunderstanding how you use the term in English.

Treshold braking is to be as close to lock up as possible, without locking up. ABS only intervenes when you actually have locked up. In theory at least, you can treshold brake on a ABS equipped car by braking just on the limit and just before ABS kicks in.


To the OP:

What is perfect weight distribution?

The ideal weight distribution for a track car is not 50/50, but probably closer to 60/40 rear bias. However, for a saloon car with a traditional front engine layout, the closer you get to 50/50 the better it is. This is also what BMW put's a lot of effort into achieving and why BMW's often is reported to have better balance than a MB AMG or Audi RS (especially a Audi since they often is closer to a 60/40 front bias).

I also used to believe that BMW's claim that 50/50 was the ideal weight distribution was a objective "truth" for all cars. However I learned from others on this forum that a rear bias is better for response and turn in, as well as more rear end grip for acceleration. But since a front engine RWD car won't be able to achieve that distribution, a 50/50 is far better than a 60/40. But not as good as a 40/60...

Very well explained. Clear and concise.

[Boss330]

Originally Posted by M6-Coupe

Boss, rarely I agree with you

[shahano]

anyone knows the exact weigh distribution of the M5?

[RPiM5]

Originally Posted by shahano

anyone knows the exact weigh distribution of the M5?

48/52 front bias.

My Fiat Abarth is horrible. 36/64 front bias. You can really feel it when maneuvering hard. It's because the engine is all the way in the nose.

An Audi RS7 is 44/56 front bias.

Porsche 911's and Porsche Cayman are sports cars built from the ground up. Their traction is vastly superior to many other performance cars due to a lot of factors but one of the big ones is weight distribution.

For a 4,400lbs car like the F10 M5, having close to a 50/50 weight distribution really makes the car feel a lot lighter than what it is during hard maneuvering. The Audi RS7 has more weight and has worse weight distribution but has that AWD to control all that weight hanging off the front of the car.

[Boss330]

Originally Posted by shahano

anyone knows the exact weigh distribution of the M5?

Sport Auto weighed the M5 and got a 51,9/48,1 distribution F/R

http://f10.m5post.com/forums/showthread.php?t=679580

[M6-Coupe]

Originally Posted by shahano

anyone knows the exact weigh distribution of the M5?

Originally Posted by RPiM5

48/52 front bias.

Originally Posted by Boss330

Sport Auto weighed the M5 and got a 51,9/48,1 distribution F/R

http://f10.m5post.com/forums/showthread.php?t=679580

And BMWNA says : 52.5/47.5 (F/R)
http://www.bmwusa.com/Standard/Conte...fications.aspx

[M54ccibo]

I believe that Porsche states the magic number, front to rear is 47/53. They've also done a ton of engineering to get that pendulum action decreased, like gradually moving the engine forward and adding very wide tires.

But with a track car reality is that total balance is the goal, and for every track the setup, including weight balance - front and back, but also crosswise - is different and a compromise.

[(H)]

Originally Posted by Used2be

The car is very poised for a heavy sedan. Is the ABS system disabled when we turn off the DSC completely? I've only done one track day so haven't explored all the possibilities with the car. If the ABS is still functional, do you mean threshold braking until you feel the ABS kick in? Or are you able to lock up the tires?

Sorry, Used2be, for the late reply, had to work for once ... Yes, as already stated, unfortunately or fortunately ABS can not be turned off with a button and will stay on even with DSC entirely off. Threshold braking is indeed the task of breaking as hard as possible without locking up the wheels.

My observation was, though, that it feels like the ///M5 does a brake modulation, i.e. instead of going into ABS mode it automatically reduces the braking force to threshold power just before ABS. I am saying so because even if I slammed the brake with two feet I couldn't feel any of the ABS rattling.