[onfireX5]

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[chassis]

Very interesting. What are the center differential technical details for xDrive?

[onfireX5]

Originally Posted by chassis

Very interesting. What are the center differential technical details for xDrive?

Same diff as the M5. My truck would fail that test with rollers on both rear and one front.

[r33_RGSport]

So lift kit would be great then.

[cfm56d7b]

One of the most interesting tests. I was impressed with one particular test when 3 wheels were on rollers. The remaining wheel still managed to provide enough traction. Thanks for sharing.

[///M TOWN]

I'd like to see a comparison between ///M xDrive and standard xDrive.

Looks like they perform very much the same.

Thank you for posting.

[Barbera335]

Originally Posted by onfireX5

Same diff as the M5. My truck would fail that test with rollers on both rear and one front.

Why would it fail? All you have to do is apply the brake with enough pressure to transfer power through your open front diff to the wheel with traction. This is basic off roading. And if your truck is relatively new the computer will brake individual wheels for you.

[bjcarls]

On the three wheel - to me it looks like it moves forward because it starts to grip the side of the roller base. Idk...or really care.

X7 did it much faster and smoother which just confuses me. I’d need to know the software and mechanical differences.

[MrFargo13]

I don't understand the point of this. I attended a driving event in 2011 where they did this same demo with the 2012 X3. And it actually came off the rollers in seconds, not minutes.

[Max Well]

Originally Posted by MrFargo13

I don't understand the point of this. I attended a driving event in 2011 where they did this same demo with the 2012 X3. And it actually came off the rollers in seconds, not minutes.

? - Apologies if I'm misunderstanding you, but the timing is in seconds, so it completed all maneuvers in 18.00 sec. If they don't complete a test section within 10 sec doesn't it stop and fail that section?

Originally Posted by bjcarls

On the three wheel - to me it looks like it moves forward because it starts to grip the side of the roller base. Idk...or really care.

X7 did it much faster and smoother which just confuses me. I’d need to know the software and mechanical differences.

The X7 40i completed it in 9:16 sec. I'm not a Physicist, but perhaps the weight of the vehicle alone allows gravity to provide more traction to one wheel? I haven't looked at their tests of smaller, lighter vehicles to see if that pans out, just thinking... And personally, not worried about those 9 seconds tbh.

[TTR]

Originally Posted by bjcarls

On the three wheel - to me it looks like it moves forward because it starts to grip the side of the roller base. Idk...or really care.

X7 did it much faster and smoother which just confuses me. I’d need to know the software and mechanical differences.

Weight? So in 1 point more pressure

[Miko M]

Looking good

And all started in 80' with Subaru's symmetrical AWD

Pioneers in AWD

[onfireX5]

Originally Posted by Barbera335

Why would it fail? All you have to do is apply the brake with enough pressure to transfer power through your open front diff to the wheel with traction. This is basic off roading. And if your truck is relatively new the computer will brake individual wheels for you.

2007. Two rollers in the back and one up front will stop it cold because the tire that is on the ground is equal to 100% braking on that point.

Not the same as going up a muddy hill with partial traction on both sides. You could put 100% pressure on the brake and torque up the converter but as soon as you let off the brake the open front differential will sense the 100% 0 % split and start spinning the roller side.

[Raikkonen]

Originally Posted by bjcarls

On the three wheel - to me it looks like it moves forward because it starts to grip the side of the roller base. Idk...or really care.

X7 did it much faster and smoother which just confuses me. I’d need to know the software and mechanical differences.

You're absolutely right in your assessment, and that's why "roller" traction test results are questionable at best.

The vehicle always ends up moving forward because of momentum, not traction.

In the real world, this does happen in something like snow or mud as tires eventually gain traction, but that's not the point of this test.

The point of these tests are to highlight the efficiency of an awd system, and its strengths and weaknesses.

In theory, in a roller test, you should be able to apply light throttle, continuously, and the car should gain traction. Time and time again, as in this video, the driver floors the accelerator, which then causes a tire to "catch" the roller, in conjunction with forward weight and momentum.

The proper way to do these tests is the opposite of what's being shown....you provide artificial traction, and real slippage (think wet ice), not artificial slippage. This way, you remove the infinite variables involved in creating a zero traction (artificial) environment, especially through something like a mechanical roller. On the other hand, a surface that provides grip has few, if any variables, assuming that the surface provides traction.

Here, you're simply watching a roller test, which could have a hundred different outcomes depending on the rollers used, and the way the vehicle is being driven.

[Salottox5m]

Most bored video to watch - bmw owes me 25 seconds of my live back

[onfireX5]

Interesting that this test did not catch a roller at high wheel speed with TC on and off.

[Logical]

Ultimate Driving Machine!!

[Sedoy]

Nothing new, xDrive have been passing this test for years.

[bimmer456]

Originally Posted by ///M TOWN

I'd like to see a comparison between ///M xDrive and standard xDrive.

Looks like they perform very much the same.

Thank you for posting.

I think this lets you do actual donuts not just sliding. On the M5 you can turn off x drive completely.

[///M TOWN]

Originally Posted by bimmer456

I think this lets you do actual donuts not just sliding. On the M5 you can turn off x drive completely.

I'm referring to a comparison between the 2 variations of xDrive on the roller tests.

I know you can turn it off on the X5M.

[ParadigmDawg]

This a more fun way to do it.

[onfireX5]

X3MC does it like this when pissing on the competitors....