[DaleHeinz]

While driving my loaner car today (while my M240Xi awaits its repairs), I was wondering about power distribution for the Xdrive. The 330i loaner I'm driving is RWD, and while under powered in comparison to my M240Xi with Dinan stage 1, it felt strangely similar when driving in a "spirited" manner. I used to have an Audi S4, and it was near impossible to get the tail to step out under power and seemed pretty well balanced front/rear. The M240Xi, though AWD, seems much more rear wheel biased when driving with some pep, and feels much more akin to a RWD car than the Audi ever did.

So, here's my question. Just how does the BMW Xdrive system work? How is power distributed? 60/40, 70/30, or is it pretty much a RWD car until the front wheels need power?

[PowerfulF22]

BMW states that Xdrive is 40/60 in normal conditions, and can distribute differently on slippery surfaces.

[vandridine]

When I bought my 240ix the dealer said it could put 90% of the power to the rear wheels. No idea if it is correct or not however.

[Ron Jeffries]

I find the xDrive on my M240i to be Very Different from the open diff RWD of my 135is. It was quite easy to get the 135is to try to step out the rear, and easy to get it to cut power since it didn't have an LSD. In the same corners with roughly the same level of aggresXXXXX assertiveness, the xDrive is clearly pulling more from the front wheels, and is both less inclined either to understeer (which the 135 was capable of) or to oversteer.

The M240i xDrive is far more stable in cornering. I suppose that would be less fun if you really want to hoon around, but I'm more about fast, smooth, and stable than sliding.

[bimmerfile]

Originally Posted by DaleHeinz

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So, here's my question. Just how does the BMW Xdrive system work? How is power distributed? 60/40, 70/30, or is it pretty much a RWD car until the front wheels need power?

This may 'splain things for y'alls.

[Maynard]

Very cool video - I'd thought that all the Audi's had the Haldex. Also cool to know the xdrive can put 100% to just one axle. I've been loving the 4wd handling profile more and more as I get used to it - thought I'd miss RWD, but I think this is better.

[DaleHeinz]

Originally Posted by bimmerfile

This may 'splain things for y'alls.

Damn good video. Thanks for the post! May have to watch it a second time, as the guy talks pretty fast with no breaks. Haha. Pretty neat to see the differences spelled out in the video. Never realized the Xdrive could distribute power between front and rear that much.

Haven't had a chance to drive an Xdrive in the snow to compare to the S4 I used to own. The S4 always felt stable and confident in slippery/snowy conditions. I bought my M240 back in early February, but D.C. area really didn't get much more than a dusting after that, so I never got a chance to compare it yet.

[bimmerfile]

Originally Posted by DaleHeinz

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Haven't had a chance to drive an Xdrive in the snow to compare to the S4 I used to own. The S4 always felt stable and confident in slippery/snowy conditions. I bought my M240 back in early February, but D.C. area really didn't get much more than a dusting after that, so I never got a chance to compare it yet.

For the 20+ years prior to buying the M235i xDrive ragtop, my wife and I always had 2 vehicles (a ragtop (camaro, firebird, Z4, 128i) for the spring thru fall and a SUV (Rav4's Subaru Forester, BMW X1) for the winter).
Then with the 2er going xDrive in 2015, we went down to 1 vehicle. During the past 2 winters in the M235xi, I have felt every bit as confident in the snow and foul weather as I ever did with any of the SUVs we owned in the past.
BTW, I only have the OEM RFT all-seasons on the M235xi and they work well enough for me in the winter (P.S. don't tell anyone else here about this last part or I'll get the "winter tire" speech).

[BEM-S4]

Originally Posted by bimmerfile

For the 20+ years prior to buying the M235i xDrive ragtop, my wife and I always had 2 vehicles (a ragtop (camaro, firebird, Z4, 128i) for the spring thru fall and a SUV (Rav4's Subaru Forester, BMW X1) for the winter).
Then with the 2er going xDrive in 2015, we went down to 1 vehicle. During the past 2 winters in the M235xi, I have felt every bit as confident in the snow and foul weather as I ever did with any of the SUVs we owned in the past.
BTW, I only have the OEM RFT all-seasons on the M235xi and they work well enough for me in the winter (P.S. don't tell anyone else here about this last part or I'll get the "winter tire" speech).

Winter tire speech ignored since we all know they're better, ground clearance aside I cannot tell you how many times I have passed SUVs parked on the side of a road at the base of a hill and happily bounced my way up in either the xDrive M235, my old S4, etc. If there's anyplace you can't go in bad weather with an xDrive 2er, you really should stay home.

[XutvJet]

Originally Posted by DaleHeinz

I used to have an Audi S4, and it was near impossible to get the tail to step out under power and seemed pretty well balanced front/rear.

Much of it has to do with the fact that the Audi has a lot more weight hanging out in front the front axle. It makes the car far more prone to understeer and less willing to rotate, especially considering that more Audis do not have a RWD biased AWD system.

[BEM-S4]

Originally Posted by XutvJet

Much of it has to do with the fact that the Audi has a lot more weight hanging out in front the front axle. It makes the car far more prone to understeer and less willing to rotate, especially considering that more Audis do not have a RWD biased AWD system.

It basically comes down to the fact that a tire can only do one thing at a time. It can accelerate, decelerate, or turn.

[Maynard]

Originally Posted by DaleHeinz

...Haven't had a chance to drive an Xdrive in the snow to compare to the S4 I used to own. The S4 always felt stable and confident in slippery/snowy conditions. I bought my M240 back in early February, but D.C. area really didn't get much more than a dusting after that, so I never got a chance to compare it yet.

Ditto w/ the other posters - the 2's are fantastic in the snow; actually makes me look forward to the snow. Right now we are in the 'doldrums' between having the summer tires on, and getting to play in the snow with the winters. Down in DC you can even get away with the performance winter tires and just keep the sport-handling party going year 'round.

[wdc330i]

Originally Posted by Maynard

Ditto w/ the other posters - the 2's are fantastic in the snow; actually makes me look forward to the snow. Right now we are in the 'doldrums' between having the summer tires on, and getting to play in the snow with the winters. Down in DC you can even get away with the performance winter tires and just keep the sport-handling party going year 'round.

Yep. That's what I did when I lived in DC/Maryland. Summer tires/performance winters (on the RWD car; AWD car got All Seasons/Performance Winters).

[Northwest240]

Originally Posted by XutvJet

Much of it has to do with the fact that the Audi has a lot more weight hanging out in front the front axle. It makes the car far more prone to understeer and less willing to rotate, especially considering that more Audis do not have a RWD biased AWD system.

Actually they do have rear-biased for the most part. The information in that video is not quite accurate. All the current Audi models using the MLB platform (longitudinally mounted engines) with the exception of the latest Q5, A4 Allroad, and A4 manual transmissions, use a Torsen quattro system with a 40/60 front/rear torque distribution. Recently older versions of these same models all use the 40/60 split Torsen. The latest models I mentioned above use the newest quattro with Ultra electronically-controlled system. Note that all S and RS Audis on MLB use the Torsen as quattro with Ultra cannot be used on any car generating 369 lb. ft. (500 nm) of torque or higher.

The A3/S3/RS3 and TT variants (MQB platform with transverse-mounted engines) use a Haldex-based system.

It's under debate what the capabilities of the quattro with Ultra are. Audi has made claims it can direct 100% to the rear or front, but with their design, it seems difficult to believe that is the case. Those who have driven in one universally say they cannot distinguish between that system and the previous Torsen-based quattro, though, which is mechanically able to distribute torque up to 75% to the front wheels and 85% to the rear wheels.

[DaleHeinz]

Originally Posted by Maynard

Ditto w/ the other posters - the 2's are fantastic in the snow; actually makes me look forward to the snow. Right now we are in the 'doldrums' between having the summer tires on, and getting to play in the snow with the winters. Down in DC you can even get away with the performance winter tires and just keep the sport-handling party going year 'round.

That is what I've decided. While she's down and out for another warranty issue, I'm having some Michelin Pilot Sport A/S 3+ thrown on. Looking forward to not having the run flats anymore. Had the older versions of the Pilot Sport A/S on my S4 and 335i coupe, and never regretted it in the D.C. area. Can't wait to see how much they've improved the tire over the years.