Kirk Pacenti, the infamous father of 27.5-inch mountain bike wheels, has patented, perhaps the simplest idea since the rotary string trimmer better known as the "Weed Whacker." It is called "Pdent Technology" and it is a 15-millimeter dent in the center of the handlebar that allows it to nest into the steerer tube. The end result is a low-profile stem which can be as short as 10 millimeters.
Pdent solves a problem that has limited stem lengths to 32 millimeters - which is the distance that marks the point where the handlebar meets the edge of the steerer tube. Before anyone starts shouting "Mondraker," a number of sub-30-millimeter stems currently exist - right down to zero-reach - but they must be made taller than optimal in order to provide room for the steerer tube clamp. Pacenti's solution gets the job done while maintaining the low-profile of a traditional shorty stem.
Pdent is a system that includes the dimpled handlebar and a matching stem. Presently, the system is only available from Pacenti, but he is actively seeking OEM partners who can take the concept to the masses. The CNC-machined dual-clamp stem is matched with a carbon bar. Prices and weights are not yet determined.
Offsets will be offered in 25 and 15 millimeters for starters, because Pacenti says that exceeding those numbers creates unstable steering as the grips of the handlebar move behind the steering axis. Fabien Barel concurs, relating that he tried zero-rise stems, but had to move the bar forward ten millimeters to stabilize the Mondraker's "Forward Geometry" steering.
Concerns about weakening the handlebar at the center where, theoretically, the bending forces are highest are unfounded, says Pacenti, who showed a computer-generated stress model that indicated the stem's two clamps arrest all the major bending moments, leaving the center of the bar almost unaffected by those forces.
Another concern is that customers are being asked to purchase a matching bar and stem for each of the two offset options. Pacenti says that he will offer bars with a ten and 15 millimeter dimple that will nest with his 25 and 15-millimeter offset stems. Logically, the deeper, 15-millimeter dimple would fit both stems, but Pacenti insists that doing so would eliminate the self-centering effect of the closely fitting bar. He also claims that the limited angular adjustment of the correctly matched Pdent stem and bar will prevent the bar from over-rotating should the stem clamps be under torqued.
Surely, those features are optimal, but in the same breath, neither are critical to the system's purpose of providing a shorter stem to the many riders and bike makers who believe that the option will turn in a better performance. If I were a customer, I'd probably buy the bar with the deepest dimple, knowing that I could upgrade to either stem option should I have guessed wrong.
So, what are my first thoughts about Pdent? It's a simple, "Why didn't I think of that?" solution for riders who want a sub-30-millimeter stem, because it maintains all of the other ergonomics of the bike's previous setup. Pdent also proves that it can be done, which should light a fire under the rear ends of other accessory makers to offer a similar product. Either way is a win for riders in need.