2012 Lexus RX Driving Impressions


We've driven RX 350 models with front-wheel drive and all-wheel drive as well as an RX 450h hybrid.

The 2012 RX 350 responds well to throttle out on the road. Part of that is the big 3.5-liter V6, part of it is the 6-speed transmission. The 6-speed automatic has a lower first-gear ratio than the typical 5-speed, so it gets the RX quickly up to velocity for merging or highway entry. Lexus told us to expect 0-60 acceleration times in the neighborhood of 7.7 seconds, and a quarter mile time of 15.7, and that's about the way it felt. We didn't go there, but top speed is electronically limited to 112 mph.

The transmission quickly selects gears based on throttle input, so you can ask for a gentle downshift just by giving it a little more gas. If you floor the accelerator, it kicks down two gears and moves out. It's also possible to select your own gears in multi-mode shifting, but the automatic's logic seemed so intuitive that we would probably drive in Auto 95 percent of the time, using the manual mode for downhill control on the highway or a long uphill when heavily loaded. There is no V8 option for the RX, but if there were, we'd wager that performance would not be much improved, and mileage would suffer.

We did not feel much torque steer in the front-wheel-drive models, particularly not in the Hybrid.

The RX 350 is not built for road racing, but more for passenger comfort. The double-wishbone independent rear suspension has a lot to do with that. Still, it has a nice, clean turn-in and good lateral grip for an SUV. Here's where its genuinely wide track (a little over 64 inches in front, a little under in the rear) contributes noticeably to agility.

We expect Lexus vehicles to be exceptionally quiet, and the RX is no exception. That said, the 19-inch wheels on the Sport Package do allow for more road input, and a little more noise and vibration seep through. The suspension is tuned slightly differently with the Sport Package, but the end result is still not as aggressive as Porsche's Cayenne or the BMW X5. To us, that's fine. We think SUVs are better at grocery-getting than corner-carving anyway. Bigger wheels, thinner tires and tighter damping tend to compromise Lexus ride quality and noise control, without delivering all that much gain in handling. So our preference is for the 18-inch wheels.

Regardless of the tire choice, we found it easy to maintain a conversation using a low tone of voice at normal speeds. Lexus pioneered the science of quietness in a car, with the result that almost all cars are significantly quieter than they were five years ago. New tricks, such as optimized wheelwell damping coatings and fender liners, have been incorporated into the RX. The underbody of the car has also received attention against wind noise. And the sixth gear in the transmission allows for ultra-quiet cruising, with less engine noise, on the highway.

All those things also hold true for the 2012 RX 450h, but because it is a hybrid, it regularly operates with the engine off altogether. During those times, noise reduction is even greater, bordering on eerie.

The brakes feel strong and progressive, with just a little squish at the top of the pedal before stronger grip kicks in. The hybrid brakes, which are regenerative, are much more smoothly modulated than earlier hybrid brakes. The transition between light braking, when the generator reclaims power, and the serious stopping power that comes on when more pedal is applied, can still be felt, but you have to look for it.

Steering effort is light, and proportioned electronically, with power-assist logic based on vehicle speed. The slower you go, the less effort required, so it can be just as appropriate in the parking lot as in the fast lane on the way to Las Vegas. Lexus uses the electric steering system on a number of its vehicles, because it reduces drag on the motor and thus, improves fuel economy. It's also more compact, so there are packaging advantages, and once you have a computer controlling steering, you can add VDIM.

VDIM is not a system easily tested in normal driving, because it requires driving out of control, and then recovering. At which point, nothing will have happened, except maybe a brief flash of an icon on the dash. But it's a system that looks at steering, braking, throttle and motion sensors in the cabin to predict what will actually happen, compared to what the driver is asking for. If there is any difference between the two, the system intervenes and selectively brakes individual wheels to correct the path of the car. It happens so fast you might not notice.

We've tested VDIM on race tracks and lonely dirt roads. It works without slowing down the car much, unlike VSC, which is the standard traction/stability control system. It's an expensive option, but one we wish was on every car.

The RX is an easy SUV to see out of, and fairly easy to keep track of the area around the vehicle when backing up or parking. Driver visibility is enhanced by small windows in the A-pillar, and by small TV cameras that track the rear and passenger-side of the RX. One camera is located in the right side mirror, the other in the rear bumper. We found we could toggle between the two views, front and side, to see how close we were to the curb or pedestrians.

We found the RX to be a relaxed and comfortable ride, so we spent time trying out some of its electronics systems.

We actuated the heads up display and found it makes it easy to stick to speed limits in unfamiliar ground. Bright white, high-contrast figures were easy to read, even heading into sunlight. It's the best we've seen so far. It's possible to project the display anywhere on the windshield; we liked it best low and to the left.

Voice recognition, something we've never really trusted, still takes a little getting used to, but the system in the RX is much closer to something we might use every day. We began by asking it to switch to channel 143 on XM, which it had no problem doing. It also seemed to quickly be able to supply the nearest gas stations, although not the cheapest prices, and turn down the air conditioning. However, when we asked it to play Grateful Dead, it did not find the channel on its own, so evidently there are limits to Hal's intelligence.

The RX 450h is offered in front-wheel drive or all-wheel drive, but the all-wheel-drive system is different; it incorporates a separate rear electric motor to power the rear wheels. Because it is a hybrid, the transmission is a continuously variable automatic and the brakes are different due to the need to regenerate electricity. And there are a few packaging and styling differences to consider when making a decision between the two. Because of the addition of electric motors, the RX 450h has 25 more horsepower than the RX 350, which compensate for a weight penalty of over 300 pounds.

Using the EPA combined city/highway ratings, both FWD and AWD versions of the hybrid get 9 mpg better fuel economy than their non-hybrid counterparts. Even with the hybrid's smaller fuel tank, it can travel 115 miles farther on a fill-up. However, at $4 per gallon, you'd have to drive close to 100,000 miles before you recouped the $6000 premium Lexus charges for the hybrid.

In short, dollar savings would be modest even if prices rise. For that reason, most current Hybrid buyers chose the vehicle because they want to drive the most fuel-efficient, cleanest SUV possible, one that reduces dependency on imported oil and reduces emissions. The RX 450h we drove averaged 23.4 mpg over 120 miles of mostly around-town driving.

The hybrid brake system uses the same ventilated four-wheel discs as the RX 350, but has an electronically controlled regenerative brake feature that charges the batteries when the brakes are applied gently. The hybrid system includes ABS, Electronic Brake-force Distribution (EBD), Brake Assist and more important, Vehicle Dynamics Integrated Management system (VDIM) as standard equipment. As we said before, we've tested VDIM on controlled proving-grounds settings, and consider it a remarkable safety system.

The hybrid can drive in three modes: Normal, Eco for best mileage, and EV Mode which allows the vehicle to operate on battery only. Lexus tech sources estimate the EV-only mode operating distance at about a mile. The EV feature is aimed at allowing the RX to be used as an electric car in closed urban areas where internal combustion engines are banned altogether, such as in parts of some European cities.

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