[watchhok]

Is it gonna make a difference in the Netherlands? Or is it a real advantage?

Yes I go on winter holidays in de Alps once a year. Still doubting because I like RWD...

thanks for your reply's

[ovekvam]

The traction is of course better with AWD, but rarely an issue if you have top of the shelf winter tires.

[donaldt]

I used to drive a Z4 3.0 in Boston, where it snowed about 5 months a year, with proper winter tyres you will be fine
go RWD

[DRIVE'R]

who knows what is the power distribution in ix? 50:50 or 40:60

[ovekvam]

Originally Posted by Subnasty

who knows what is the power distribution in ix? 50:50 or 40:60

If you mean E30 325iX, it used to be 37:63. For new xDrive cars, it is continuously variable over a large range.

[rickk]

RWD (with winter tires) ofcourse.

Makes no sense to waste money/weight/ride height/fun on 4WD for the really small advantage you might have once a year.

[Pavit]

Doesn't xdrive (or 4wd per say) gives more grip and anti-slip capabilities to a car?

Like when driving on slippery wet roads, steep cornering, et al ?

[ovekvam]

Originally Posted by Pavit

Doesn't xdrive (or 4wd per say) gives more grip and anti-slip capabilities to a car?

Like when driving on slippery wet roads, steep cornering, et al ?

You don't get more grip from having AWD, but you distribute the forward traction forces over several tires. This makes the car more stable, also in corners. The maximum cornering speed will still be the same.

When driving around ice tracks, you notice the AWD advantage mostly during acceleration out of tight corners. You can get a lot more power down.

The extra weight up front is a disadvantage at corner entry, so RWD cars can usually brake slightly later than the AWD version.

[KAIXIN]

Originally Posted by Subnasty

who knows what is the power distribution in ix? 50:50 or 40:60

It is front 40 : rear 60, please see attached link
http://www.m-power.com/_open/s/varlink1.jsp?lang=en

It looks the x-drive edition for M135i is quite interesting as well. I am wondering for RWD, what kind of additional fun do we get in the daily driving experience - tail can dance in the rainy days? And in track, how does it compare to AWD?

[ovekvam]

Originally Posted by KAIXIN

It is front 40 : rear 60, please see attached link
http://www.m-power.com/_open/s/varlink1.jsp?lang=en

It looks the x-drive edition for M135i is quite interesting as well. I am wondering for RWD, what kind of additional fun do we get in the daily driving experience - tail can dance in the rainy days? And in track, how does it compare to AWD?

Basically you get more traction and stability with AWD. RWD gives you a more tail happy car, and less traction interference in the steering. The added weight and drivetrain loss of the AWD system will take away a little bit of performance.

[KoenG]

pro's:
- way better traction, seen the massive beast the engine is.
- easier to handle during fast driving (less overpower risk).
- will be faster on low speed circuits or acceleration during massa transfers (cfr. leaving a roundabout, or a chicane) in 1st,2nd and 3rd gear.
- weight distribution is still ok.
- winter/snow compliant.

con's:
- 75kgs extra weight.
- a bit slower on high speed circuits.
- For the die hard fans of powersliding probably RWD is better.
- extra consumption, but very limited.

There is no difference in radial grip, since both cars have 4 wheels and the same tires.

Seen the delta in pricing in Belgium is incredibly small, I'd take it with Xdrive.

[BMW-RaceR]

My point of view

RWD Pros:
-More fun and better to drive, summer AND winter
-Cheaper to buy
-Cheaper to run, more fuel efficient
-Lower weight - equals better driving experience and performance (braking "nimbleness", etc.)
-Better handling (and maybe better steering feel?)

RWD Cons:
-Should have an LSD and its not available as an OEM option.
-Could have problems with steep hills in rough winter conditions


AWD Pros:
-Better off-the-line-tracion
-Better traction (up winter hills) and stability, especially on low grip surface

AWD cons:
-Less engaging to drive
-More expensive
-Higher fuel consumption

[KoenG]

BMW RaceR, when you want effortless fast driving, I'd still go for the Xdrive.

When you drive the Xdrive, I'am certain you'll confirm it is much more foolproof and relaxing. Of course, not everybody associates an M135i with relaxing. But I guess that in +90% of all driving conditions, this prevails and determines the daily experience with the car.

Take note, it weights more, but the weight is favourable located: under the center of gravity. So it is not certain that it negatively impacts the composure/dynamics of the car during fast driving.

Besides, price difference between RWD+AT and Xdrive+AT is really ridiculous small, just like fuell efficiency impact.

[BMW-RaceR]

People have different view of things.
Someones effortless fast drive is another persons boring drive.
Relaxing= not engaging
Foolproof=compromised driving experience made for people who are not into driving

When reading car reviews:
Handles very safe on the limit: Extreme understeer
Safe handling when pushed: Understeers

I consider everything above 1400kg to be very heavy. 1300kg+ is also a bit on the heavy side. Some cars certainly hide their weight better than others, but on the same platform 75kg is a decent amount of weight. Especially when the car is already above 1400kg and you are used to lightweight cars.

I just prefer RWD over anything else. I see why some people prefer AWD, but its just not my choice.

[ovekvam]

Originally Posted by KoenG

Of course, not everybody associates an M135i with relaxing. But I guess that in +90% of all driving conditions, this prevails and determines the daily experience with the car.

But in 90 percent of the driving conditios you are probably driving too relaxed to benefit from the AWD anyway.

In slippery conditions, AWD feels safe, but that is also a risk. It is easy to drive too fast with a sure-footed car, considering that the AWD version doesn't stop any quicker than the RWD car...

[dchao]

RWD + front engine = tendency to understeer.

This is why xDrive is useful, it will brake inner wheels and put more torque to the outer wheels, and therefore, dial in some over steering.

xDrive will make off-the-line acceleration faster, and cornering more secure. I think, the it should make this this M135i more exciting to drive.

[ovekvam]

Originally Posted by dchao

RWD + front engine = tendency to understeer.

This is why xDrive is useful, it will brake inner wheels and put more torque to the outer wheels, and therefore, dial in some over steering.

xDrive will make off-the-line acceleration faster, and cornering more secure. I think, the it should make this this M135i more exciting to drive.

RWD and front engine has nothing to do with understeer. You can set up a car like that to have no understeer at all. If the car weight is biased towards the front (like the AWD version), it will have a natural tendency to understeer.

And why is more torque going to the outer wheels with AWD? That doesn't make any sense to me.

[KoenG]

Is the Xdrive capable of torque vectoring to each wheel independantly like the Audi quattro sport set-up? When it is, there is no doubt: go for Xdrive all the way, including driving fun and sheer vehicle dynamics.

When I wrote "foolproof" and "relaxing", I meant that you can drive the holy smoke out of it, while it remains loyal to the traject you steer it in to. This under conditions where the RWD version has its' rear axle struggling for grip and you're on the verge of overpower, throwing the rear out, requiring instant counter lock to save your car.

There is no evidence that the Xdrive is more understeer, I believe that the center of gravity is moving a bit lower and a bit backward. Good conditions for even better dynamics!

Of course, +75kg is never good a thing, but maybe this is more than just compensated with the good elements that Xdrive brings.

[ovekvam]

Originally Posted by KoenG

Is the Xdrive capable of torque vectoring to each wheel independantly like the Audi quattro sport set-up? When it is, there is no doubt: go for Xdrive all the way, including driving fun and sheer vehicle dynamics.

There is no evidence that the Xdrive is more understeer, I believe that the center of gravity is moving a bit lower and a bit backward. Good conditions for even better dynamics!

I don't think the xDrive does torque vectoring, but the e-diff does this.

I don't understand how you mean the X-drive moves the center of gravity backwards. The center of gravity is usually between the front seats, and pretty much all the extra hardware for the AWD is located ahead of them.

[KoenG]

Originally Posted by ovekvam

I don't think the xDrive does torque vectoring, but the e-diff does this.

I don't understand how you mean the X-drive moves the center of gravity backwards. The center of gravity is usually between the front seats, and pretty much all the extra hardware for the AWD is located ahead of them.

You're right, it moves it downwards, but also forwards, and that is not a good thing. My mistake!


But you're right, probably less dynamic behaviour then: The vehicle roll is a bit less, but the yaw will incline more to understeer like you wrote.

[ovekvam]

But if you have a slightly front heavy car with a stable AWD system, the car can be tuned more towards oversteer with swaybars and spring settings to compensate. The car is probably set up towards understeer from the factory, but check out how nicely balanced the WRC rally cars are. With dedicated tuning, anything is possible...

[KoenG]

Originally Posted by Sol01

man you are good

+1!

btw, didn't find anything about weight distribution F/R on the Xdrive on the web... Since the driveline is entirely longitudinal, the damage done could be very limited. Mass is much more concentrated around the center of the car than transversal mounted drivelines.