BMW X5 performs impressively well when equipped with one of the V8 engines. Power from the 4.4-liter V8 is seamless, with the redline arriving at 5800 rpm. The six-cylinder 3.0i isn't in quite the same league and works best when paired with the automatic transmission.According to BMW, the 3.0i automatic accelerates from 0 to 60 mph in a quick 8.6 seconds, the 4.4i in a very quick 7.4 seconds, and the 4.6is in a startling 6.5 seconds.
The performance of the 4.6is would be quick for a sports sedan. For an SUV, it's amazing. Its performance allows the 4.6is to compete comfortably against the Mercedes-Benz ML55 AMG. ML55 comes with an AMG-tuned V8 rated 342 horsepower and 376 pounds-feet of torque, giving the M-Class Mercedes nearly identical 0-60 performance. We doubt that many X5 owners will drag race their neighbors. But they will notice how the 4.6-liter V8 makes terrific sounds when they step hard on the gas. And how smooth, responsive, and quiet it is when driven around town.
Shifting is silky smooth in normal driving situations. The automatic transmission offers the Steptronic mode, allows a choice of automatic or semi-manual control. Notching the lever to the left puts the transmission into Sport mode and enables the manual override; then a simple quick nudge forward or backward ratchets the transmission up or down one gear. X5's Steptronic is executed perfectly. A quick downshift makes passing on two-lanes safer and smoother.
Handling is stable and comfortable, with less twitching and head toss than in the Mercedes M-Class. (Compared to the Mercedes-Benz ML430, the X5's track is one inch wider, and the BMW rides 2.2 inches lower.) That's not to say the X5 is soft. It feels firm in the twisties and at high speeds. It can be driven like a sports car. On the freeway, the X5 changes lanes with the lightest of touch and with total precision. X5 can feel choppy, particularly when trundling at low speeds over a bumpy road while holding on to a hot cup of coffee. The choppy ride is pronounced with the sports suspension that comes with the optional Sport Package.
Overall, X5 is among the best-handling SUVs, although whatever else you drive will likely prejudice your opinion. If you get out of a regular truck-based SUV and into an X5, you'll be amazed at its handling. If you get out of a BMW sedan, however, you'll find that the X5 does not inspire the same confidence. BMW claims that its test drivers have circled race courses in the X5 nearly as fast as they can in a 328i sedan. This is probably true for experienced drivers who know their own limits as well as those of the vehicle they are driving. But most of us find the X5 is a tall vehicle that leans more than a sedan when going through corners.
Huge four-wheel disc brakes (ventilated in front) incorporate every electronic trick known to man. They are easy to modulate, and, they enable the X5 to stop as quickly and securely as the BMW 7 Series luxury cars. The 4.6is model gets bigger brakes and the rear brakes are ventilated; add the steamroller tires and the 4.6is really stops.
3.0i comes standard with a manual transmission. That sounds sporty, but we didn't like it. Clutch engagement is quick, and the torque characteristics of the engine (a bit abrupt at throttle tip-in) make smooth, brisk takeoffs a challenge. Lose concentration for a moment, or hurry the process a bit, and it's easy to stall at intersections, which is particularly annoying because the power-adjustable steering column starts moving while you're trying to restart the engine. We also found the manual transmission awkward when braking and downshifting for a turn, and then accelerating away. Attaining a smooth driving technique is challenging. A good driver may find it challenging to drive the 3.0i smoothly. A poor driver, one who moves the steering wheel about unnecessarily, will make his passengers uncomfortable with head toss. Also, the performance advantage of the manual transmission is not compelling. X5 3.0i can accelerate from 0 to 60 mph in about 8.6 seconds with the automatic or 8.1 seconds with the manual.
Heading off the highway in any X5 is fine as long as you don't attempt the Rubicon Trail. The X5 is not designed for serious off-road use. However, in a drive through a muddy test track, it proved capable of staying on course and not getting stuck. The X5 comes with a permanently engaged all-wheel-drive system that, not surprisingly, seems more appropriate for a high-performance sport sedan than for an off-road truck. It does not use a transfer case and does not offer low-range gears. But the X5 is loaded with electronically controlled systems to assist it when the traction turns poor. There's ASC (Automatic Stability Control), DSC-X (Dynamic Stability Control), CBC (Cornering Brake Control), DBC (Dynamic Brake Control), ADB (Automatic Differential Brake), HBA (Hydraulic Brake Assistant) and HDC (Hill Descent Control). We don't have room to explain all this alphabet soup here, but trust us, it all works; and it all contributes significantly to the X5's outstanding handling. These systems can detect when a trailer is hooked up and take appropriate action if the tail starts wagging the dog. Much of this technology has been adapted from BMW sedans, while other systems are new to the X5.
Hill Descent Control, a superb system developed by Land Rover, controls the brakes automatically on steep downhill grades. This provides an eerie experience, as you must keep your feet off the pedals as you steer the X5 down a steep, slippery slope. Hill Descent Control keeps the wheels from slipping and prevents the vehicle from going too fast for conditions. The driver can control the speed of the descent using the cruise-control buttons. It's a great feature for steep driveways in the winter, but practice is helpful.