[Ron Scott]

Originally Posted by gthal

Not I...

Just discussing these issues many xDrive owners seem to get defensive for some reason. I didn't see anyone here bash xDrive... .

LOL. Who? Me?

Originally Posted by gthal

Yeah, OK... tell us how Mr. Smart Guy. Tell me how xDrive increases traction in braking and turning?

Buddy, get your xDrive and enjoy already OK...? You'll love it.

[gthal]

Originally Posted by Ron Scott

LOL. Who? Me?

Buddy, get your xDrive and enjoy already OK...? You'll love it.

Ron, if I said something that was incorrect, please tell me where and point me in the right direction. I'm more than happy to correct my mistakes. If something I said was taken as "bashing" then someone needs to consider whether they are a little too touchy about this.

Hopefully when/if I do end up with an AWD car, I'm not as sensitive as some.

[BMWinGE]

Does the M3 or M5 come in an Xi version? Just saying.....

[Falafel Combo]

Originally Posted by gthal

Ron, if I said something that was incorrect, please tell me where and point me in the right direction. I'm more than happy to correct my mistakes. If something I said was taken as "bashing" then someone needs to consider whether they are a little too touchy about this.

Hopefully when/if I do end up with an AWD car, I'm not as sensitive as some.

Agreed. Ron is a bit touchy today. BTW, I personally didn't take any of this as bashing. Nothing wrong with having a little lively debate.


Few issues have the tendency to polarize BMW drivers so quickly. xDrive VS RWD. 3xx VS 328 VS 335. Turbo VS NA. MT and Auto.


We all drive. The same. Car!


Hopefully we don't see any Leather VS Leatherette threads soon!

[Elk]

Originally Posted by The X Men

Not only can AWD come of a corner faster but it can enter into one almost as fast as a RWD.

Unfortunately, this is not the case. The AWD cannot enter as quickly as a result of understeer and weight.

It is simply a matter of physics. If 40% of the available front wheel traction is used to accelerate, this is 40% less available to steer the car. The more throttle is applied in an AWD (or front wheel drive) the less the car can turn. More weight additionally decreases cornering ability; a lighter car corners faster.

While your RWD Bimmer is drifting thru a turn, the AWD will power its way thru with no slipping what so ever.

This is also untrue.

The only circumstance when AWD can put down more power is when the rear wheels of RWD have insufficient traction and the front wheels have additional traction available not already being used to corner (see above).

At the limits, an AWD car must brake harder prior to entering a turn as it cannot corner as quickly. Many drivers trail brake AWD to enable quicker turn-in with the weight transferred onto the front wheels as this increase front tire grip. The driver than must wait before adding throttle until the car is more straightened out. Remember, adding throttle decreases AWD cornering.

Understeer is comfortable for a street driver however. To recover, all he need do is lift the throttle.

As far as additional weight, we are talking less than 300 pounds here, about as heavy as having an adult male in your car. . . . Unless you track your car, you will not notice any benefit of RWD on a public road.

You have very heavy friends.

300 pounds is a tremendous amount of additional weight when it comes to performance. This is approaching a ten percent increase and roughly equivalent to losing 30 horsepower. As to whether a driver will notice the weight, many will. Consider how many notice the ~100 pound difference of the 328 and its affect on handling.

The upside of xDrive is its ability to move forward in slippery conditions. Given equivalent tires, an AWD easily out accelerates a RWD in snow, even more so if there is a hill to climb. This can be wonderful.

Instead of thinking as xDrive as compromised in handling, think of RWD as compromised in straight line acceleration. Both are great choices, with advantages to each.

[woderd]

Bro... RWD sucks.. You will NEVER convince a AWD owner anything different because they know the truth. Thats why they was smart enough choose AWD instead of shitty RWD

LOL

[The X Men]

Originally Posted by Elk

If 40% of the available front wheel traction is used to accelerate, this is 40% less available to steer the car.

LOL, if your formula is true, then FWD cars which use 100% of front wheel traction to accelerate will have 100% less available to steer the car. 100% less would mean there is no steering and the FWD cannot turn

AWD simply have a advantage in turns, thats why most rally cars are AWD. Drifting thru a turn might look cool but losing traction in any form will not help accelaration.

[bnekic]

^ +1

[Elk]

Originally Posted by The X Men

LOL, if your formula is true, then FWD cars which use 100% of front wheel traction to accelerate will have 100% less available to steer the car. 100% less would mean there is no steering and the FWD cannot turn

This is not how it works. Every tire has X amount of traction available to turn, accelerate or stop. Whatever percentage is used to perform one task is not available to use the others.

In a front wheel drive car, any traction used for acceleration is unavailable for steering. Thus, a front wheel drive car cannot turn as well when it is accelerating; it is already using a portion of its traction to accelerate and cannot use it to turn.

AWD simply have a advantage in turns, thats why most rally cars are AWD.

Nope. Not even close. Rally cars are AWD for quicker acceleration on the slippery surfaces on which they run.

Unlike in road racing were RWD rules and the cars turn as late as possible, rally cars complete their turns well prior to the apex of the corner. In fact, rally cars countersteer after loading the front by braking (weight transfers to the front, increasing grip and lessening the car's tendency to understeer) and sliding the rear end out to set up the earliest possible straight line out of the corner so they can get back on the throttle.

The pendulum turn is the standard rally car turn. It you watch a rally car, it approaches a corner from the inside of the corner, opposite of roadracing. It turns away from the corner and then quickly turns into the corner to pendulum the rear end around. The driver then countersteers. This is what rotates a rally car around the corner. It is sliding sideways. This is the quickest technique for this form of racing. It does not create multiple G's of cornering force however.

It is interesting that marketing has convinced so many that AWD handles better when the reality is otherwise. A couple of performance driving courses will easily resolve this lack of understanding.

[gthal]

Originally Posted by Elk

This is not how it works. Every tire has X amount of traction available to turn, accelerate or stop. Whatever percentage is used to perform one task is not available to use the others.

In a front wheel drive car, any traction used for acceleration is unavailable for steering. Thus, a front wheel drive car cannot turn as well when it is accelerating; it is already using a portion of its traction to accelerate and cannot use it to turn.


Nope. Not even close. Rally cars are AWD for quicker acceleration on the slippery surfaces on which they run.

Unlike in road racing were RWD rules and the cars turn as late as possible, rally cars complete their turns well prior to the apex of the corner. In fact, rally cars countersteer after loading the front by braking (weight transfers to the front, increasing grip and lessening the car's tendency to understeer) and sliding the rear end out to set up the earliest possible straight line out of the corner so they can get back on the throttle.

The pendulum turn is the standard rally car turn. It you watch a rally car, it approaches a corner from the inside of the corner, opposite of roadracing. It turns away from the corner and then quickly turns into the corner to pendulum the rear end around. The driver then countersteers. This is what rotates a rally car around the corner. It is sliding sideways. This is the quickest technique for this form of racing. It does not create multiple G's of cornering force however.

It is interesting that marketing has convinced so many that AWD handles better when the reality is otherwise. A couple of performance driving courses will easily resolve this lack of understanding.

Yep... true.

The first thing you learn when you begin to get serious about track time/racing is the way braking, acceleration and turning all interact together with the tire. Hence why beginners do not brake and turn at the same time because the car can't do both efficiently. No different than acceleration and turning. Tires like to deal with force in one direction at a time... i.e. braking OR acceleration OR turning. Trying to do more than one thing with the tire at the same time results in poor performance of each.

P.S. to the sensitive people... this is not a comment about xDrive, it is a comment about basic traction principles. This is not meant to offend, bash or in any way put down AWD cars.

[Joopster]

Well, I have 2012 335i -- without xDrive -- and it is amazing in the snow. Not to mention, my new Blizzak LM-60 winter tires are the keys to winter driving success.

[JulieDriving]

Ever since I've joined the forum 3+ years, the heated arguments about x-drive vs. RWD haven't stopped.

What's funny is those who think that their choice of car is superior in every circumstance. Thankfully, there are those that take the time to offer correct and balanced information for those that are (or were, like me) wondering.

[BMWinGE]

What a silly thread, I just don't understand some of the Xi owners arguments. No one has shown any documented proof that in BMW sedans, coupes, etc the Xi version offers more performance in non-slippery situations. I get that is a good option for all weather capability, but there is nothing that says it improves overall performance in the F30. You cannot use other manufactures cars with AWD as an an example for your justification, because that is their "thing". AWD is not BMW's "thing", but RWD is.

[Falafel Combo]

I personally paid extra for the xDrive, knowing that I was buying a compromise.


My opinion has never been that xDrive is 'a better performing car', but only that xDrive+all seasons performs better than RWD+Snow in snow/wet/slippery conditions. It will get you out of corners quicker in wet conditions. It will accelerate faster off the line in dry conditions, and if it does not, it sure as heck feels like it. It will be more balanced, and significantly decrease the incidences of the car fishtailing or loosing traction in snow/ice conditions. It will get you up a slippery/snowy hill without breaking a sweat.


In every other imaginable situation, it's a compromise. Compromise to ride height, weight, weight distribution, sport suspension, gas mileage, ...


Just my opinion and observations from personal experiences. And yes, I personally agree these threads are silly, but they make for good reads. I'm entertained.

[bnekic]

Originally Posted by 328inGE

What a silly thread, I just don't understand some of the Xi owners arguments. No one has shown any documented proof that in BMW sedans, coupes, etc the Xi version offers more performance in non-slippery situations. I get that is a good option for all weather capability, but there is nothing that says it improves overall performance in the F30. You cannot use other manufactures cars with AWD as an an example for your justification, because that is their "thing". AWD is not BMW's "thing", but RWD is.

BMW has been doing AWD since 1982, but your right it's not there thing lol.

One of the performance advantages of AWD is launching. AWD is what let me get awesome 60 foot/1/4 mile times running all-season tires with my Evo VIII. While the guy next to me needed super sticky performance tires in his RWD car. It was nice being able to drive to the track and back home with no tire modifications.

[Seagull]

xDrive vs RWD - I now realize and see the difference more clearly. I use to have an e90 335xi and now I have an f30 335i. Both had/have snow tires, and I've finally had big enough dumps to compare.

After a week of off an on snow, and snow up to or past the center caps of my wheels in a single dump, I have to say this is what I miss form the XI/xDrive:

1. Pretty well ( or the feeling of ) 100% certainty of not getting stuck or having to worry about losing momentum and getting stuck
   
2. Not worrying about turtling or having the car sit on the snow such that the rears get no traction
   
3. Not slowing down to a crawl ( less than walking speed ) while traction control kicks in for constantly for 15mins as I travel over unplowed roads
   
4. Not have the ENTIRE wheel well gap filled with snow which, over night freezes into solid blocks of ice, impeding the steering. With the extra 10mm on the XI, it would more easily cake off. This one was a surprise to me, and I realized this would be very handy/nice to have that 10mm extra clearence. 10mm would definitely make a difference. I actually had to take my car to a spray booth to specifically target blasting/melting/clearing this area. I could hear the scraping on every turn or bump otherwise. All those guys in CA or southern US who have virtually zero wheel gap and push the limits of tire width would not survive long in any real snow conditions. Which is fine for them, since they won't need to. I use to envy that look ( to an extent ) but now I know it can't be for me, or my geography. Its a fish out of water.

Now granted, sometimes the RWD and XI would behave similarly - for example if the entire section of road was equally slippery due to black ice or mash potato snow. But with the xi/xDrive, I'd probably feel more confident in these conditions. RWD in snow = I can get by. XI/xDrive in snow = unstoppable.

BTW, I don't regret my RWD. The point of my post is to inform others, so they make an informed decision that they can live with. Whether it is driving feel or some number/measurable specification, know what you want and what you are gaining and giving up.

After that..... ENJOY IT

[bnekic]

Oh I just remembered some guys on here said the xDrive only helps when gas is applied, that's false.

xDrive relies on the ABS and DSC to transfer up to 100% power to the front or rear axle. The gas has nothing to do with this process.

[The X Men]

Originally Posted by Elk

This is not how it works. Every tire has X amount of traction available to turn, accelerate or stop. Whatever percentage is used to perform one task is not available to use the others.

I agree with you that FWD cannot turn as well when accelarating, but your percentage is all wrong, the percentage is definitely not proportional.

Originally Posted by Elk

Rally cars are AWD for quicker acceleration on the slippery surfaces on which they run.

If your RWD is drifting thru a turn, you are slipping, therefore, you just agree that AWD will go thru a turn faster.

[gthal]

Originally Posted by bnekic

Oh I just remembered some guys on here said the xDrive only helps when gas is applied, that's false.

xDrive relies on the ABS and DSC to transfer up to 100% power to the front or rear axle. The gas has nothing to do with this process.

Unfortunately it is not false (however, being open to the possibility of being incorrect, point me in the direction of factual information and I will change my opinion). Your own post just said it transfers "power"... there is no power without gas. Your own comment proves what I and many others have been telling you

From BMW's website...

Dynamic Stability Control (DSC) is only activated if it is necessary to redistribute engine power when conditions deteriorate: the system effectively controls both oversteering and understeering by engaging the electronically controlled multiple-plate clutch, which reacts within a tenth of a second, to distribute up to 100% of the engine power to the front or rear axle and then back to the normal 40:60 ratio. With the BMW xDrive all-wheel drive system each axle optimally uses its traction to provide stabile ACCELERATION out of every bend.

xDrive redistributes the power (which, I think we can agree requires gas pedal involvement) as needed. It provides superior traction on acceleration (which can be while cornering if gas is applied or in straight acceleration). I think this confirms what we have been telling you... xDrive makes a real difference on acceleration (i.e. gas pedal involvement) but is not a factor in braking or turning (when not under power). It is very simple and, as many have said, NOT a bad thing, not bashing or not putting down xDrive. It is just a description of how xDrive works. I'm not sure why you keep arguing that it does more than it actually does... it doesn't need to as it is great as is. I believe Acura's AWD system actually applies small amounts power to outside wheels to improve turning even if you are not on the gas pedal but this is not a characteristic of xDrive to my knowledge.

RWD cars also have DSC too that works similarly with the exception it doesn't transfer "power" to the front axel. I'm not sure if this is clear yet but hopefully it is now. Braking and turning are the same for xDrive and RWD cars unless gas is being applied... then xDrive is different.

P.S. I said I wasn't going to do this anymore but couldn't help myself

[MNBart]

This thread was a ridiculous read. Get whatever you want to spend your hard earned money on and be happy with it.

I would like to add something that has not been mentioned so far: tan leather is soooooo much worse for denim wearers. If you got tan leather, you can't wear jeans.

[gthal]

Originally Posted by bnekic

BMW has been doing AWD since 1982, but your right it's not there thing lol.

One of the performance advantages of AWD is launching. AWD is what let me get awesome 60 foot/1/4 mile times running all-season tires with my Evo VIII. While the guy next to me needed super sticky performance tires in his RWD car. It was nice being able to drive to the track and back home with no tire modifications.

Absolutely true!!

[gthal]

Originally Posted by MNBart

This thread was a ridiculous read. Get whatever you want to spend your hard earned money on and be happy with it.

I would like to add something that has not been mentioned so far: tan leather is soooooo much worse for denim wearers. If you got tan leather, you can't wear jeans.

There's actually a lot of good info in this thread and then, as you mention, a lot of silly comments too I agree... get what you like and what best suits your needs.