RIDE QUALITY
The Niner RIP 9 RDO 4-Star XT 29 ENVE is a fun and playful-feeling bike. It isn’t the go to for jumps and stunts, but when it came to weaving through technical singletrack, the RIP was hard to beat. At 67 degrees, its front-end geometry was the steepest in the test, on par with all-mountain rigs. That gave it a nimble feel that ripped through technical terrain and up switchback climbs. The geometry made it really comfortable both in and out of the saddle.

STIFFNESS-TO-WEIGHT/POWER TRANSFER
Exceptional. Carbon from rim to rim made the Niner RIP 9 RDO 4-Star XT 29 ENVE the most responsive bike in the test. Wherever we wanted to put this bike we could do it with minimal effort. We only had to think about lifting front end or pushing the rear tire and it happened. A lot of this is due to the Constantly Varying Arc (CVA) suspension, which links into the chain tension to counter bobbing during pedaling. The linkages rotate in opposite directions so they can react independently to the forces of pedaling and absorbing terrain bumps. Basically, CVA keeps the bike in contact with the ground without sucking up any of the forward power.

CLIMBING/EFFICIENCY
Niner’s high-tech carbon forming process sets the mold under pressure so they can use less resin, cutting weight to the frame construction. But when it comes to the Niner RIP 9 RDO 4-Star XT 29 ENVE’s class-leading efficiency, the carbon rims are the major difference maker. They reduce rotational inertia, making it easier to push the tires uphill. This is similar to how the weight of your shoes has a bigger impact on leg fatigue than the heavy pack on your back. Lighter rims actually have a bigger impact than cutting the same static weight off other parts of the bike. So even though this is already the lightest bike in the test, it felt even lighter. The rear triangle is asymmetric, cut out on one side to provide more clearance for the rear tire, sucking it in closer to the seat. This creates a more balanced climbing position and creates more clearance for wider tires, too.

DESCENDING/HANDLING
The more responsive front end of the Niner RIP 9 RDO 4-Star XT 29 ENVE detracted from its downhill stability. That’s not to say it wasn’t solid on the way down, just not as stable as the Rocky Mountain, Norco, or Specialized. With 150mm of travel in the rear, 160mm in the front, as well as 29-inch wheels, the “squish” felt similar to the other bikes in the test, adding plenty of control off drops, big hits and small jumps.

COMPONENTS: DRIVETRAIN, SHIFTING AND BRAKES
The Niner RIP 9 RDO 4-Star XT 29 ENVE would have scored lower on the components if not for the carbon rims. The Shimano XT drive train and brakes are on the lower end for the category. The Fox Factory front and rear shocks are par for the course. The Integra dropper seatpost was dependable. And the bike is compatible with 29 and 27.5 plus size tires. The jump up to carbon rims is a huge addition to this bike (about a $2,000 addition), and the key to its winning this test.