In this month's Tire Talk, we'll evaluate the Bridgestone Dueler A/T REVO tires, a set of Finn F1000 cast-aluminum wheels, and as a special bonus, we A/B-tested and will report on the benefits of installing new shocks. The dampers we road-tested are a set of Tokico Trek Master R/Ts. Our test mule this month was an '00 Nissan Xterra; not one of the best-handling SUVs on the market, but we thought this would be a challenging test case for the new rolling stock and dampers.
Our Xterra test rig racked up 90K on the odometer, and the tires we had on it were severely worn, so we didn't even try to baseline the stock combination. It would've be futile anyway, which is why we threw in the shock evaluation. First we mounted, balanced, and installed the new Bridgestone Dueler A/T REVOs on the FINN F1000 wheels and got a baseline in terms of ride quality and handling without the Tokico shocks installed.
The stock wheel is 15X7 inches, but our replacement was 15x8 inches, which increased the volume of the air space inside the wheel; this required an adjustment in tire pressure. We started with 30-psi cold pressure and noted that road shock attack is more aggressive than when we reduced cold pressure to the factory recommended 26 psi. At 26-psi cold, we observed a 30-psi warm pressure, running at 70-75 mph on the freeway portion of the test loop. With the vehicle unloaded, we wanted to see around 32-psi running pressure, so we bumped the cold pressure up to 28 psi to compensate for the larger volume. Road shocks and vibration were noticeably smoother at 26 psi than at 30 psi, but road feel wasn't as crisp. We seemed to get a good balance of road feel, vague though it was with the worn shocks, and ride comfort at 28 psi. As an aside, tires at 30-psi cold pressures were extremely smooth, if a little too harsh. This confirms to us the claims that Bridgstone technology makes a very concentric (round) tire.
We experienced some oversteer gain with the new tires before installing the Tokico Trek Master shocks. It was hard to distinguish at the time if it was roll steer, or a characteristic of the tires. After installing the Tokicos, we discovered that it was the dead shocks on the vehicle. They didn't control weight transfer on corner entry, so when the body rolled as we began the turn, the sudden weight transfer increased the rear slip angle, turning the vehicle more than the steering angle would indicate. Also, when accelerating off a corner near the limit of traction, we felt a pronounced oversteer. We also found that the road feel came back with the Tokico shocks.
In our lane change test, the vehicle handled OK, although, the lack of body control caused the Xterra to oversteer a little when initiating the lane change, and was significant when attempting to stabilize the SUV after the lane change. This required some steering correction to keep the vehicle from spinning out. After we installed the Tokicos, it was much more controllable and driveable at the limit in this abrupt avoidance maneuver.
The Bridgestone Dueler A/T REVOs are very communicative. They gave lots of feedback (more so with good shocks) on the level of grip available. They growled first, then barked when reaching their limit, and lost grip in a very nice slow decay of traction. The tires were very forgiving, but had a ton of cornering grip for an A/T-type tire.