The concept of having one bike to do everything is something that flies directly in the face of the usual “N+1” logic of cyclists. What we are looking for in developing our own concept for a Do-It-All bike is not a single bike to kill a quiver of bikes, but rather a single bike that allows you to ride wherever you want, however you want, over whatever terrain you might come across.
Frame Design Details
To develop our concept of the Do-It-All Aero (DIAero) bike we created our first prototype; the DIAero P-01. We chose to build our first prototype with very aggressive geometry in order to test the extreme of what we think the geometry of a DIAero bike should be. While a headtube angle of 72 degrees, and a chainstay length of 420mm tend to remain fairly on-trend, the BB drop of 90mm and a 57mm length effective top tube designed for a shorter 80mm stem push the envelope for most bikes that are expected to spend some of life on the road.
As a Do-It-All bike, we stressed the need for comfort for a long day of riding and to be able to accommodate the kit that one would need for such a ride. To that point we are running two bottles in frame (room for the big bottles on both cages), a dropped top tube to help with the standover height in tricky situations, and a 27.2mm seatpost and dropped stay combo to add compliance for the rider and stiffness for the rear triangle with added bonus of better aerodynamics. We also added in an additional tube to tie the top tube to the downtube in order to stiffen up the front end from a fore/aft perspective.
Recently we took this P-01 frame out for a shakedown ride to determine what works, what doesn’t, and where we need to improve. First thing out of the gate that we notice is the ideal rider fit. This is a bit easier as we know our own fit numbers and how we like to feel on the bike but it was still good to know we hit the nail on the head. The second sensation that we feel is one of the utmost stability. The massive BB drop creates a great sense of being “in” the bike rather than “on” the bike. The downside to this is that the bike lacked that same sense of immediacy that bikes that are this stiff and tucked in tend to have. A hard out-of-the-saddle effort confirms that while hard efforts were effective, they don’t provide the same sensation of speed that we have come to expect from a bike with as stiff a rear end as this.
Hitting the first descent of the day brings that same sense of stability to the fore providing absolute confidence when descending rough gravel roads. The front end remains planted despite pushing hard into corners and it is never unsettled by rough segments of road. Unfortunately, this awe-insipiring descending stability does have one problem in that the more normal head tube angle/trail and short chainstay were at odds with the low BB giving the bike a sense of quickness of steering but a slow roll rate which translates into some interesting moments during quick left-right-left corner transitions. The bike never feels like it wants to snap from one turn to the other but rather wants to stay on the line it is set on. We feel that this is something that can be overcome with a different riding technique, but we are still not sure if that the benefits are there to encourage a rider to relearn how to steer their bike.
When traversing rougher terrain we discover that while the rear triangle is indeed stiff under acceleration, it does not in any way negatively impact the overall feel of the bike. Road buzz is non-existent, and the large impacts are easily damped by the frame proving that we have achieved our goal of designing a frame for a very compliant ride.
As a whole we consider this bike to be a successful prototype but still a ways from a finished product that we would be willing to put under customers. We have achieved our goals of creating a smooth riding bicycle with a rear end stiff enough for hard accelerations and a front triangle stiff enough to give direct feedback to the the rider in turns. Where we miss though is the mismatch between the insane stability of such an aggressive BB drop and the quicker steering geometry. The divergent feelings of immediate turn-in and reluctance to transition will hinder riders who want to jump on this bike and still receive some hint of a racing thoroughbred hiding under the endurance outer appearance.
Moving forward we will continue to ride this bike and put it to the test to determine in all conditions what aspects of this bike work and what don’t and this input will be fed back into the next iteration of this new idea of bike.