The R500’s 5.0-liter single-overhead-cam V8 seems to have been powering Mercedes models since spats were cool, but it remains one of our favorite engines. Here it’s partnered with the company’s equally venerable full-time all-wheel-drive system and its new seven-speed automatic. Mercedes says 35 percent of the R-Class’ components are shared with the ML-Class sport-utility vehicle, and this powertrain is a large part of that. This is the same setup you would get in an ML500.
As satisfying off idle as it is at its 6,000-rpm redline, the V8 is rated at 302 hp at 5,600 rpm and 339 lb-ft of torque at 2,700 rpm. It’s plenty. Despite the R500’s portly 4,845 pounds, it sprints from zero to 60 mph in just 7.4 seconds, and through the quarter-mile in 15.2 seconds at 91 mph. That’s about the same performance as we’ve measured for the BMW X5 4.8is, which has 53 more horsepower than the R and a fraction of the cargo room.
The seven-speed transmission has a lot to do with that performance. Although we think it could downshift a little quicker, it’s geared perfectly and clicks off swift upshifts when the driver has his foot down.
We tested the R’s handling with the suspension in the Sport setting, and were pleased with the vehicle’s agility. Although its steering is a little slow, body roll is well controlled, and the R’s all-wheel drive, standard 18-inch wheels and tires and ESP stability control give this very large vehicle surprising grip. We managed a best slalom run of 57.4 mph, which means the R outhandles most SUVs.
It can outstop them, too. Big four-wheel disc brakes, with 13.8-inch front rotors and standard ABS and BrakeAssist, haul this big vehicle down from 60 mph in just 126 feet.