You won’t see Levi racing this: Specialized’s new Shiv

By Nick Legan with contributions by Aaron Hersh

Editor’s Note: This article was updated on October 27 to add that Specialized will offer the same UCI-legal Shiv module in 2012 that the company has for the past seasons.

In a bold assertion of triathlon’s growth, Specialized has produced a tri-specific Shiv that completely ignores UCI regulations on framesets. Tube shapes go well beyond the UCI’s 3:1 ratio and the fit is better suited to longer events, instead of super aggressive World Tour positions. Specialized won’t be introducing a new UCI-compliant Shiv for 2012. But maybe we’ll see some details taken from the tri Shiv when they do unveil a new model for the time trialists out there.

Fit:
The most important changes to the new Shiv are frame geometry and fit adjustability. The 2011 Shiv might have been an aerodynamic success, but it created fit problems for many triathletes. It could only accommodate a single aerobar, the headtube didn’t lengthen as the bike got larger and the basebar could not be raised. As Specialized engineer Luc Callahan put it, “The Shiv was positioned really aggressively, and honestly it didn’t work for everybody.”

All five sizes have a relatively tall stack height compared to the reach value and these dimensions scale linearly from the extra-small frame size to the extra-large.

The stack and reach values for the five frame sizes (all with 700c wheels) are:
X-Small: Stack 495mm, reach 365mm
Small: Stack 515mm, reach 385mm
Medium: Stack 540mm, reach 405mm
Large: Stack 565mm, reach 425mm
X-Large: Stack 590mm, reach 445mm

The 2012 Shiv features an extremely adjustable aerobar and has a traditional steerer tube. This allows the use of readily available stems or Specialized’s own aero stem to clamp virtually any aerobar on the market. The aero stem can be positioned directly on top of the head tube or it can be lifted 25mm or 50mm. The stem has two clamp positions that alter its reach. The shorter orientation creates a 60mm stem and the longer position lengthens it to 90mm.

Aerodynamics:
Specialized ignored the UCI rules governing frame tube shapes. Those rules state that a frame’s tubes cannot be more than three times deeper than their width. This limits aerodynamic performance and is the reason other brands, such as Trek, are using truncated airfoil tube shapes. Foregoing those rules gives Specialized the freedom to create the Shiv’s shockingly deep head tube and down tube. The head tube is 4.1 times deeper than it is wide (4.1:1 ratio). The down tube has a 3.9:1 ratio, the fork blades have a 3.4:1 ratio and even the seatpost violates UCI regulation.

Specialized road product manager and aerodynamicist Mark Cote explained that the aspect ratios were tuned for the specific wind conditions faced by different portions of the bike. According to Cote, the rear of the bike experiences wind at a narrower yaw angle at a lower speed than the front of the bike because of interference created by the bike and rider, therefore these parts of the bike need different tube shapes. In addition to the radically deep tubes, Specialized added a fairing behind the steerer stack extending above the top tube. Many aerodynamicists say a gap behind the steer stack creates substantial drag and this fairing, called the Control Tower, helps minimize that drag. Cote says the difference is not massive, but is measurable in the wind tunnel.

Instead of using an integrated front brake, Specialized opted for an external caliper. Cote says the extra drag created by the exposed housing is tiny and he believes the ability to easily adjust the brake offsets that aerodynamic sacrifice.

Hydration:
In addition to the tri-specific fit, the 2012 Shiv hides an internal bladder to keep hydration needs covered without adding to aerodynamic turbulence.

The Shiv’s Camelbak-style bladder, called the Fuelselage, is hidden in the head tube and down tube. The bladder slides into the frame through the top tube directly behind the stem. It’s sealed with a rubber stopper that can be removed to refill the bladder on the go. The hose pops out of the frame behind the stem and lays onto the aerobar extensions. Specialized cleverly placed a magnet in the valve and a matching magnet in a strap that can be positioned anywhere on the bike to hold the hose and keep it from flopping around. Two valves are available, one is a bite valve and the second is an upturned opening without any seal. The bladder holds a little more than 20 ounces of fluid, depending on frame size, and can be removed from the bike to be cleaned.

The new Shiv still has a single bottle mount on the seat tube for the use of a traditional bottle and cage.

So, what about the roadies?
Specialized will offer the same UCI-legal Shiv module in 2012 that they have for the past seasons. According to Specialized’s Nic Sims, there are no plans for a new UCI-compliant Shiv in 2012. 2013 perhaps? We’ll have to wait and see.