Intense just dropped the news: they’ve been working on a dedicated 29er project, which they insist is not, “just a bandaged, modified M16.” According to Intense, key components of the welded aluminum frame's architecture were specifically designed and chosen to both accommodate 29-inch wheels and allow for the geometry and wheel path Intense was looking for. There are plenty of visual cues to support that. First off is the lower swingarm rocker, which pivots concentric with the bottom bracket. That, in conjunction with a seat tube tunnel, allowed Intense to minimize the longer chainstays needed to accommodate 29-inch wheels while providing ample clearance for DH-width rubber and muddy World Cup venues. The shock is positioned low in the chassis and most of the linkage elements are tucked out of view inside the tunnel or behind the crankset. It is apparent that Intense has been working on their 29er DH project for quite a while.
The obvious question is this: "When will we see these on the trail?" Actual production bikes are a ways off. Intense is still in the active prototyping stage, as evidenced by all the raw, aluminum frames you can see here. Intense riders, however, will be racing the bikes this season. Intense is making no claims about carbon versions at this time. Molds are a long way off at this point, as the company fully expects to make changes as the race season progresses.
What is absolutely clear, is that the team sees the benefit of going big with the wheels. During Intense's team camp, racers did back-to-back testing with identical 27.5 and 29-inch wheel prototypes.
When they averaged the rider's times over twelve runs, everyone was consistently faster on the 29er rig. More importantly, riders felt they could push harder and closer to the edge on the the 29er, and could manage to do so more consistently over varied terrain and tracks. In World Cup racing, where fractions of a second make all the difference, the bigger wheels are going to make a difference themselves.
Some of the key elements that brought Intense's latest 29er DH bike into existence: The CNC-machined link that pivots concentric with the bottom bracket is in the lower center of the image, and above that are the two halves of the seat tube tunnel. When it comes to fabricating a rolling chassis, Intense has one of the industry's better R&D facilities. RockShox's ability to provide a dedicated 29er fork, however, was the most critical piece of the puzzle.
The concentric lower rocker link is tucked inside of the frame's bottom bracket housing.
The bike's tunnel shock design and fully triangulated rear end make for strong, flex-resistant structures.
Small head tubes require a lot of reinforcement, but help to reduce the tall stack height dictated by 29-inch-wheels.
Jack Moir rocks an Intense 29er prototype in Southern California during the test sessions.
From the Designers
Axle path: We wanted to keep the wheel path manageable, where we had a nice rearward trajectory, but without need for extra gadgets or a wheelbase that grows exponentially and alters geometry, like on high-pivot systems. We were able to get a nice initial rearward wheel path, with good bump compliance.
Kinematics: Basically, the suspension rate is linear with a nice supple beginning, solid support at sag, and good bottom-out resistance. That provides good tunability at the damper.
Architecture: Fully triangulated front and rear sections to keep these independently stiff. The tunnel configuration up front allows a really solid connection of bottom bracket, headtube, seat tube, and it supports all the pivots well. The large concentric pivots around the bottom bracket for the main link makes for an extremely stiff setup and allows more room at the chainstay yoke for better clearance and correct geometry.
Secret weapon: Intense partnered with Cesar Rojo, the founder of Cero Design in Barcelona, Spain. Cesar has been instrumental in developing their new kinematics and geometry.
Wheel-travel: We ended up at 180 to 200mm travel (so far), as we feel the 29-inch wheel's ability to maintain momentum and roll over and through obstacles negates the need for more travel. Keeping the wheel travel reasonable also stabilizes the geometry during the course of a race run.