Assisting the XC90's powerful ascents and controlled descents of The City's undulating contours was a four-speed version of the adaptive automatic transmission Volvo calls Geartronic, electronically controlled and with a winter mode. On the dry pavement of San Francisco, it made the power flow smoothly from gear to gear. The base five-cylinder engine also is mated to a Geartronic box but with five forward speeds.
At the top of one steep crest, I paused and looked across the sparkling, deep blue waters of San Francisco Bay, and then I felt the XC90's weight shift to the forward tires. Rolling down the face of the ground swell, I felt the sudden exhilaration of speed, like the rush of body surfing across the face of a towering wave. Suddenly a pedestrian entered a crosswalk halfway down the hill. I hit the brakes, four-wheel ventilated discs measuring 12.0 in. up front and 12.1 in. at the rear. Augmented by four-channel ABS and Emergency Brake Assistance, which senses how quickly the brake pedal is pushed and boosts pressure if it detects a "panic" situation, they quickly and confidently halted the Volvo's progress.
Leif Noren, project manager for the chassis and powertrain, explained that many of the technological advances in the XC90 were adapted from other Volvo family members. "The experience and system knowledge from the XC70 is taken over to the XC90 regarding the active chassis systems and transmission. The DSTC [dynamic stability traction control] with all its functionality is basically the same. The RSC [roll stability control] is the only function added to the XC90. The electronically controlled awd from Haldex was introduced in the S60 last year and is now on the XC70 and XC90. Together with the four-wheel traction-control system known as TRACS, the power is distributed automatically to the left or right side and to the front or rear axle to optimize the best grip and to provide a stable and predictable driving behavior."
In normal driving, most of the engine's power is directed to the front wheels. When detecting front tire slip, the system begins to flow power to the rear wheels in as little as one-seventh of a wheel revolution. In extreme cases, such as on slick ice, all engine power can be diverted to the rear wheels. It's quick, transparent and, as I soon would learn, is not at all detrimental to the XC90's sporty nimbleness.
The modern, sedan-like independent suspension-MacPherson strut front and multi-link rear-combines with a relatively long wheelbase of 112.6 in. to lend the XC90 high degrees of stability and agile handling. I felt in total control because of its firm and responsive chassis, strong and efficient driveline and well-tuned brakes. In fact, I felt entirely comfortable in this new, for me, kind of vehicle.
Noren later joined me for the famous "moose test." To demonstrate the XC90's new stability systems, a coned course was set up and we were instructed to drive through the sequence at 35, 40 and 45 mph. Having never attempted this, my speed was conservative, but when I took the XC90 through the cones at 30 mph, it was incredibly stable. The power-assisted rack-and-pinion steering system was direct and responsive, helping me navigate through the cones without taking any out. Wanting to see Volvo's new roll stability control (the only active stability-enhancement system on the market) work during extreme situations, I asked Noren for assistance.