AWD Vs. RWD - Just How Much Quicker Is One Compared to the Other?

However, not all motorsport competitions are the same, which is why circuit racing is still very much dominated by rear-wheel-drive cars. Then why are more and more manufacturers making their performance models all-wheel-drive? Audi does it, Mercedes-AMG does it, and now even BMW, one of the last to abdicate, has the M5 xDrive on the road and the M3 and M4 xDrive just around the corner.

To find an answer, we need a scientific approach. Well, at least as scientific as you can get with a 600+ hp car and a soaking wet track. The car in question is none other than the BMW M5 we mentioned earlier, with this particular example being the Competition trim. Anticipating the backlash from tainting the M5 with an all-wheel-drive system, the Bavarians have done a brilliant thing with the M xDrive.

Essentially, the M5 can be RWD, RWD-biased AWD, or full AWD, depending on what the driver wants (or how brave they're feeling). What that means is that the M5 is the perfect vehicle to see which of the two options - RWD or AWD - is the quickest, and by how much. The same car with the same tires, the same driver, and on the same track - with all variables removed, it's all down to the drive system and the drive system alone.

The guys at Tyre Review decided to test all three settings of the M5 (RWD, AWD Sport, and AWD) in both dry and wet conditions. The car would first have to accelerate from zero to 60 mph (97 kph), then do a hot lap around a circuit for the handling section of the test.

Predictably, the difference in the wet between the three settings - particularly between the RWD and AWD - was huge in the acceleration test, but not that great over the timed lap. For the 0-60, we're looking at 8.6 seconds for RWD, 4.1 seconds for AWD S, and 4.0 seconds for AWD, whereas the lap took 53.08 seconds in RWD mode, 50.79 in AWD S, and 50.7 seconds in AWD.

No big surprises there, but the real question is whether the different settings will still have a significant impact on dry asphalt. And here's the answer: 0-60 took 3.8 seconds in RWD, 3.0 seconds in AWD S, and a blistering fast 2.9 seconds in AWD (numbers don't include the one-foot rollout).

The surprise comes on the handling course where the gap from the wet test pretty much carried over in the dry as well. It's true, it did get smaller while the course itself (and the time it took to complete it) grew, so even though we're looking at almost two seconds, proportionally speaking it is smaller.

However, it's still pretty significant, which means that, at least as far as the BMW M5 Competition is concerned, AWD is by far the quickest option, regardless of conditions. Here are the numbers: 1:11.44 in RWD mode, 1:09.74 in AWD S, and 1:09.8 in AWD.

Of course, this test is a little skewed since the whole point of opting for a rear-wheel-drive car over an all-wheel-drive one is the fact that it's lighter. The BMW M5 Competition has the same weight regardless of the mode it's operating in, so perhaps a better test would be to use a BMW M3 and an M3 xDrive, when the latter becomes available. For now, though, this is the best you can do to settle the argument, and we think it provides a pretty good insight into the benefits of both propulsion systems.