BMW xDrive
- Explained Simply
- What is xDrive
- How Does it Work
- How Much Does it Cost
- xDrive Pros And Cons
- Is xDrive Worth it
xDrive is one of the best all-wheel-drive systems on the planet. It is capable and reliable with a good dose of BMW driving magic. So, if you want to learn is it worth the extra weight and cost, you’ve come to the right place.
SECTION 1
BMW xDrive Explained
In this section, I’ll cover the fundamentals of the xDrive system. So, if you are new to BMW and would like to better understand the xDrive, you’ll love this section.
What is xDrive?
xDrive is a proactive all-wheel-drive system from BMW. The system can actively control the torque of all four wheels.
It was introduced in 2003 when the first BMW X3 (E83) was released. The system is part of the standard equipment of high-end BMW modes (X6, X7, M5, etc.)
A BMW with xDrive is basically all-wheel drive. This means that all four wheels can be supplied with engine power.
However, the activation of the xDrive system is dependent on demand or torque and not always in equal parts. BMW models without xDrive have front or rear-wheel drive, depending on the model.
What is The Point of xDrive?
If a car can distribute its drive power to four instead of two wheels or tires, it simply has more options for dealing with slippery situations.
In addition, an all-wheel-drive car drives off more smoothly and safely in the wet, snow, and ice – all in all, a BMW with xDrive creates a confident feeling.
The only danger here is that you will assess your driving skills better than they are.
All-wheel drive is always an advantage if you want to pull heavy loads, for example, a caravan, a boat, or a horse trailer.
The most important thing to remember is that all benefits of any AWD system come only while the vehicle is accelerating.
How Does xDrive Work?
The xDrive relies on the two core components to control the torque distribution between the wheels.
The transfer case (ATC) is responsible for torque distribution between the front and rear axles.
The DSC (Dynamic Stability Control) is responsible for torque distribution between left and right wheels.
BMW relies on two xDrive systems
In models based on the classic BMW drive concept (front-engine lengthways, rear-drive; e.g. 3, 5, X5), the xDrive works electronically.
This means that normally the engine power is only directed to the rear wheels. Only when the electronics recognize within milliseconds that the traction is no longer sufficient is the front-drive switched on.
The torque distribution depends on the model. If necessary and for a short period of time, 100 percent of the drive energy can also flow to the front wheels.
BMW models of the smaller series (e.g. 1 Series 2020, 2 Series Active Tourer, X1) with a transverse front-engine, on the other hand, rely on a front-wheel-drive concept.
This means that they share the basis with the BMW subsidiary brand MINI – all-wheel-drive is still offered on certain models. A hydraulic Haldex clutch now works here, similar to the system that is also used at Volkswagen (Golf, Passat, etc.).
If the traction on the front wheels is no longer sufficient or if an excessive speed difference between the front and rear axles is detected, part of the engine power is also directed to the rear wheels. If the coefficients of friction allow it, a fundamentally rear-oriented design is also possible.
As a result of developments in recent years, the classic all-wheel drive disadvantage of increased consumption has meanwhile moved into the background.
It is still true, however, that an all-wheel-drive like the xDrive cannot override the laws of physics. Especially on snowy or wet roads, the following applies with all-wheel drive: take your foot off the gas.
Table of Contents
Difference between xDrive and sDrive
BMW offers two fundamentally different types of drive for its vehicle models with xDrive and sDrive. But xDrive is not the same as xDrive and there are now also differences with sDrive. We show the advantages and disadvantages of the drives.
The BMW with xDrive has all-wheel drive
A BMW with xDrive is basically all-wheel drive. This means that all four wheels can be supplied with engine power. However, the activation of the xDrive system is dependent on demand or torque and not always in equal parts. BMW models without xDrive have front or rear wheel drive, depending on the model.
In the past, all-wheel drive vehicles were often off-road vehicles, but now more and more regular cars are equipped with 4WD drives. With more powerful vehicles in particular, it is advisable to direct the power to all four wheels instead of just two. The advantages of the road all-wheel drive are primarily based on improved traction and driving stability, not only in ice and snow. The newer all-wheel drive systems, such as the xDrive from BMW, differ significantly from older systems. As a rule, they do without heavy and fuel-efficient transfer or reduction gears and instead rely on so-called hang-on solutions.
BMW relies on two xDrive systems
In models based on the classic BMW drive concept (front engine lengthways, rear drive; e.g. 3, 5, X5), the xDrive works electronically. This means that normally the engine power is only directed to the rear wheels. Only when the electronics recognize within milliseconds that the traction is no longer sufficient is the front drive switched on. The torque distribution depends on the model. If necessary and for a short period of time, 100 percent of the drive energy can also flow to the front wheels.
BMW models of the smaller series (e.g. 1 Series 2020, 2 Series Active Tourer, X1) with a transverse front engine, on the other hand, rely on a front-wheel drive concept. This means that they share the basis with the BMW subsidiary brand MINI – all-wheel-drive is still offered on certain models. A hydraulic Haldex clutch now works here, similar to the system that is also used at Volkswagen (Golf, Passat, etc.). If the traction on the front wheels is no longer sufficient or if an excessive speed difference between the front and rear axles is detected, part of the engine power is also directed to the rear wheels. If the coefficients of friction allow it, a fundamentally rear-oriented design is also possible.
As a result of developments in recent years, the classic all-wheel drive disadvantage of increased consumption has meanwhile moved into the background. It is still true, however, that an all-wheel drive like the xDrive cannot override the laws of physics. Especially on snowy or wet roads, the following applies with all-wheel drive: take your foot off the gas.
This is what the sDrive does
At BMW, the term sDrive no longer only stands for rear-wheel drive vehicles. Models that rely on the front-wheel-drive concept also use this designation if they do not have all-wheel drive. In the BMW configurator, you can find this designation for X1 and Z4, among others. So sDrive indicates that only one axis is driven.
Depending on whether only the rear or the front wheels are driven, the driving behavior differs significantly. With front-wheel drive the vehicle is “pulled” by the engine power, with rear-wheel drive it is “pushed”. In general, the drive via the rear wheels is perceived as more dynamic and sporty, whereas the front-wheel drive (e.g. BMW 1 Series 2020) is considered a safe drive variant. If the drive wheels lose traction with front-wheel drive, the vehicle usually only pushes over the front wheels. The so-called understeer is also considered easier for the less experienced driver to control.
If, on the other hand, the drive wheels in a rear-wheel drive vehicle (e.g. BMW Z4) lose grip, one often gets into the driving state of oversteer. This means that the rear of the vehicle pushes into the outside of the curve – a driving behavior that can usually only be controlled by experienced drivers. However, the general advantage of rear-wheel drive is that, in contrast to front-wheel drive, the influence of the drive cannot be felt in the steering (especially when accelerating rapidly or when exiting a curve at high speed).
Conclusion: xDrive or sDrive?
Which drive concept you ultimately decide on remains primarily a question of taste and cost. Often, however, BMW already accepts the decision and only offers certain models with all-wheel drive. Incidentally, this also applies to the powerful M models. Regional differences can also contribute to the purchase decision. Who at the north
Is BMW xDrive Full Time AWD?
The BMW xDrive all-wheel-drive system not only thinks for itself, but it also thinks ahead. … xDrive is the permanent all-wheel-drive system from BMW that works under normal driving conditions with a basic distribution of drive torque of 40 to 60 percent between the front and rear axles.
In models based on the classic BMW drive concept (front-engine lengthways, rear-drive; e.g. 3, 5, X5) the xDrive works permanently. BMW models of the smaller series (e.g. 1 Series 2020, 2 Series Active Tourer, X1) with a transversely installed front-engine, on the other hand, rely on a front-wheel-drive concept.
. This means that normally the engine power is only directed to the rear wheels. Only when the electronics recognize within milliseconds that the traction is no longer sufficient is the front-drive switched on. The torque distribution depends on the model. If necessary and for a short period of time, 100 percent of the drive energy can also flow to the front wheels.
BMW models of the smaller series (e.g. 1 Series 2020, 2 Series Active Tourer, X1) with a transversely installed front-engine, on the other hand, rely on a front-wheel-drive concept. This means that they share the basis with the BMW subsidiary brand MINI – all-wheel-drive is still offered on certain models. A hydraulic Haldex clutch now works here, similar to the system that is also used at Volkswagen (Golf, Passat, etc.). If the traction on the front wheels is no longer sufficient or if an excessive speed difference between the front and rear axles is detected, part of the engine power is also directed to the rear wheels. If the coefficients of friction allow it, a fundamentally rear-oriented design is also possible.
This neat trick mimics the function of differential lock, found on proper off-road vehicles like the Jeep Wrangler.
Can xDrive be Turned Off?
Only the latest M models have an option to turn off the M xDrive via the iDrive system. By default, the xDrive system in BMW can’t be turned off by the driver.
Driving Dynamics
Does xDrive Make a Difference?
How Good is xDrive in The Snow?
Driving in snow and ice is no fun. Most drivers quickly reach their limits in winter with a two-wheel drive. You can make better progress with all-wheel drive – but that too has its disadvantages.
xDrive BMWs equipped with proper winter tires (not all season) are great in snow. But remember, xDrive doesn’t help you stop!
White snow and blue sky – most people are happy about such weather in winter. Especially if you are on a skiing holiday, you will hardly have any objection to a closed snow cover. It looks completely different when you sit in the car. Because then snow and ice quickly turn the ride into a slide.
The biggest problem with snow and ice is traction. The coefficient of friction on a dry road is around 0.8 mu (µ). With ice, it is only around 0.2 µ.
That means:
The tire can only transmit a little power.
Drivers of rear-wheel-drive cars notice this particularly quickly. Compared to front-wheel drive vehicles, there is comparatively little weight on the axle.
The result: the wheels spin even faster on the slippery road surface. That’s why owners used to often put sandbags in the trunk in winter.
In modern BMWs with rear-wheel drive, this is usually no longer necessary due to better weight distribution (~50:50 since E36 3 series).
But if you want to be on the safe side in the cold season, you should opt for xDrive. “That can have real advantages in winter,” explains Sander. Because four tires bring more power to the road than two driven wheels. “You can also get up a mountain much faster with a vehicle like this in winter,” explains Paulus. And a 4×4 car often makes better progress when cornering quickly.
Is xDrive Rear-Wheel-Drive Based?
Can You Drift With xDrive?
With rear-wheel drive, it’s easy to drift: DSC OFF, second gear, full throttle, let the rear end out, counter-steer, and keep drifting with fine gas play – not the fastest, but the most spectacular method of cornering.
The situation is different with all-wheel drive, which is supposed to counteract this effect. And it does so.
However, BMW has left a gap open in its xDrive system in order to indulge in the joys of controlled skidding, especially in winter.
Prerequisite: deactivate all electronic traction controls (DSC OFF), which reinforces the rear-wheel-drive character of the car. A slightly more powerful engine is also not unimportant, which was definitely the case with the BMW 640i xDrive GT with 340 hp.
Then: automatic gearbox on manual, second gear, fully depressing the gas pedal before entering the bend, turning quickly, letting the rear end, counter-steering – voilà, the big touring car is drifting.
Important: Always look in the direction you want to drive – i.e. through the side window.
Sure, but it’s pretty tricky. The speed at which the xDrive equipped BMW loses traction is much higher compared to RWD. This requires some additional rally-style skills.
DTC enables the skilled driver to drift around bends in a controlled process, enjoying more excellent driving dynamics.
What About The Driving Feel?
While all-wheel drive offers advantages in slick weather, some compromises exist, especially in performance cars like the M340i.
The famous BMW 50:50 weight balance is compromised by 1%.
So, if you are into instrumented tests, the RWD will beat AWD on a sunny track day.
Yet all-wheel drive does make sense for some folks, especially if parts of the country see winters like the last two with more frequency, and it’s good that those who make that choice for their M235i will end up with a satisfying, enormously capable, and fun car. Us? We’ll brave the cold in a sub-$45K rear-drive M235i with a manual and spend some of the savings on winter tires.
It is safe to assume that for 95+% of drivers, there is no applicable difference in the driving feel. And very little to the other 5%. If you are in that 1% of the last 5%, you’ll need to try both.
Going from the RWD sedan/coupe to AWD, the feel is pretty different, and you’ll need time to get used to it.
How Good is xDrive on The Track?
Reliability And Maintenance
How Reliable is xDrive System?
The Most Common xDrive Problems
Maintenance Compared to RWD models
The only maintainable item on the xDrive system is the transfer case oil, but it is crucial. The oil change interval is determined by BMW’s computers that calculate the slippage of transfer case clutches.
Unfortunately, the driver is not informed about the need to change the transfer case oil. The only way is to read out the vehicle’s fault memory with a diagnostic device, which is regularly done at the “Vehicle Check” service.
Depending on the driving style, the transfer case oil can last anywhere from 50k to 150k miles.
The other tell-tale signal is jerking under hard acceleration, caused by either worn oil, clutch disc plates, or the difference in tire diameter between the front and rear axle.
xDrive is one of the most reliable all-wheel-drive systems. Some earlier models had problems with worn actuator gear and the front propeller shaft that could break and cause substantial damage to other systems (engine/transmission). Still, these were replaced with improved ones via technical campaigns.
The solution for a worn transfer case actuator gear is quite simple, as you can see in this video from FCP Euro:
Most of the problems on xDrive systems are caused by worn transfer case oil and using wrong or worn tires. In the worst-case scenario, worn transfer case oil or clutch can destroy front CV joints and shafts.
The same applies to tires. The difference in tire circumference between the front and rear axles should always be in the 1% range.
E7x front driveshafts.
The Cost Compared to RWD
What is The Price of xDrive?
Depending on the model, the xDrive will set you back for between $2k and $3k when ordering a new car.
The good thing is that the xDrive system doesn’t depreciate as the car itself. So, in most cases, you’ll get your money back.
Does xDrive Use More Fuel?
BMW vehicles equipped with xDrive systems on average use 3-6% more fuel, depending on the model and engine. The more powerful the engine, the less is the difference.
BMW xDrive Maintenance Cost
The prices for transfer case oil change differ dramatically between BMW dealers. For example, the oil change in the transfer box, including old oil disposal, is 10 FRU x your dealer price. And one Q of oil. Between $200 and $400. The flat labor rate for X3 G01 M40i is 50 minutes.
xDrive Repair Cost
What About Depreciation?
It seems that the xDrive system is the only thing on BMW that doesn’t lose money.
Price comparison table with RWD new and a few years old.
Modifications And Tuning
Is BMW xDrive Worth it?
BMW xDrive Pros And Cons
Is BMW xDrive Worth Having
If you are asking yourself this question, then it probably is.
My personal opinion:
Which drive concept you ultimately decide on remains primarily a question of taste and cost. Often, however, BMW already makes the decision and only offers certain models with all-wheel drive. Incidentally, this also applies to the powerful M models. Regional differences can also contribute to the purchase decision. Experience has shown that those who live by the North Sea will use the all-wheel-drive less than those who mainly travel in the Alpine region.
However, the following applies: Even all-wheel-drive drivers should not blindly trust the technology, recommends Dekra. All-wheel drive offers drivers more stability on slippery roads. They are not a substitute for careful driving. “When you have reached the top, you will have the same problems in the four-wheel-drive vehicle as any other driver,” says Tüv expert Sander. Because downhill the all-wheel-drive offers no advantages. However, drivers of large SUVs often forget this. “At first, many were driving too fast in their large SUVs and then got off the road,” Paulus observed himself. Because even in the all-wheel-drive vehicle, the following applies: The laws of physics cannot be overridden.
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How Does xDrive Works?
In contrast to the previous BMW all-wheel-drive system with its rigid power distribution between the rear and front axles, the xDrive concept uses an electronically controlled multi-disc clutch to distribute the drive power from the rear axle to the front axle at lightning speed, continuously and fully variable, and this in every driving situation.
The system immediately recognizes when a change in the torque distribution is necessary and reacts extremely fast, usually even before a wheel spins.
This means that each wheel receives exactly the amount of torque currently required for maximum propulsion.
The result is a clearly noticeable gain in driving safety and driving stability as well as agility and traction, especially on winding roads. When dynamically negotiating a curve, xDrive directs the optimum drive force to the respective axis at all times and minimizes understeer or oversteer.
In normal straight-ahead driving, however, xDrive usually distributes the engine torque between the front and rear axles in a ratio of 40 to 60 in order to maintain the typical BMW driving impression of a rear-wheel drive.
The driver benefits permanently from the advantages of the xDrive system, as the power flow is continuously adapted to the respective driving situation.
The following examples illustrate this:
>>> Illustration: multi-disc 60:40 start
When starting off under normal conditions, the multi-plate clutch is closed up to around 15 mph. This ensures maximum traction.
>>> Illustration: 90:10
The system then distributes the engine torque variably between the rear and front axles, depending on the condition and nature of the road surface.
In curves, the lightning-fast redistribution of the power flow reduces understeer or oversteer:
>>> Illustration: Owersteer
If the rear of the vehicle pushes outwards (oversteer), xDrive closes the multi-disc clutch more strongly and thus directs more drive power to the front wheels.
In this way, the rear wheels can build up more lateral force again and the vehicle stabilizes.
>>> DSC intervention
Thanks to the combination with the DSC, the system recognizes the tendency to oversteer very early and intervenes before the driver even notices the changed driving situation: the BMW with xDrive drives through the curve as if on the proverbial rails.
>>> Understeer
The same applies to severe understeer: If the vehicle strives out of the curve via the front axle, this understeer tendency is recognized by the information from the DSC system, and the torque for the front axle is reduced – in extreme cases up to 100 percent rear-wheel drive!
As a result, the driver can move the BMW with xDrive almost with the agility of a rear-wheel-drive BMW on serpentine stretches, for example.
Only when the risk of oversteer or understeer can no longer be compensated by the variable power distribution alone does the DSC chassis control system stabilize the vehicle with braking interventions.
XDrive effortlessly compensates for even abrupt gas changes: while at least 200 milliseconds pass between the pressure on the accelerator pedal and the build-up of engine torque, the multi-plate clutch closes or opens completely within 100 milliseconds.
When parking, the multi-disc clutch opens completely and the drive is reduced to purely rear-wheel drive. There is neither unpleasant tension in the drive train nor influences on the steering.
On inclines with slippery surfaces such as ice or snow, the locking effect between the front and rear axles prevents individual wheels from spinning. This means that DSC only needs to take the gas off or brake the wheels when the road surface conditions are much more difficult.
When driving further, the locking effect also significantly reduces the risk of loss of longitudinal or lateral force on individual wheels. This gives the driver a much safer and more agile driving behavior.
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The core of xDrive: Electronically controlled multi-disc clutch
The core of xDrive is the electronically controlled multi-disc clutch in the transfer case. It regulates the flow of power within milliseconds. In the extreme, the front and rear axles can be completely decoupled or rigidly connected to one another. The rigid connection corresponds to the function of a 100 percent longitudinal lock-in conventional all-wheel drive.
The function of a differential lock, i.e. the distribution of power to both front and rear wheels, is performed by DSC with the help of electronic brake intervention: If a wheel spins without transmitting power, it is braked. This means that the differential in the axle drive automatically distributes more power to the wheel on the other side of the axle.
BMW xDrive Explained
In this chapter, I’ll help you get a handle on the fundamentals. So if you’re new to BMW, or want to make sure you’re on the right track, you’ll love this chapter.
What is xDrive?
xDrive is the proactive all-wheel-drive system from BMW.
What is The Point of xDrive?
If a car can distribute its drive power to four instead of two wheels or tires, it simply has more options for dealing with slippery situations. The main advantage of xDrive system is that it can distribute the power to the wheels (or just one) which have the most traction.
How Does it Work?
The xDrive system relies on two core systems to distribute the engine torque to the wheel, or wheels with the greatest traction.
- The torque distribution between axles is handled by a transfer case with an electronically controlled multi-disc clutch.
- The torque distribution between the left and right wheel is handled by Dynamic Stability Control system (DSC).
