Cannondale Synapse Hi-Mod: A comfortable racing bike in an endurance frame

Determined not to have it be pigeonholed as a bike for older and slower riders, Cannondale engineers and industrial designers built the new 2014 Synapse with “Synapse Endurance Race Geometry” (“S.E.R.G.”) and have, from the outset, made racing part of its pedigree.

Its first use in a race was the Strade Bianche in the Chianti region of Tuscany, and Cannondale rider Moreno Moser won the race on it. Peter Sagan subsequently won Ghent-Wevelgem and Brabantse Pijl (Brabant Arrow) on a Synapse Hi-Mod, along with second places in Ronde van Vlaanderen (Tour of Flanders) and E3 Harelbeke. Sagan also finished second in Strade Bianche, but he was riding a Super Six EVO in that race.

“I was at first reluctant [about using the Synapse] until I tried it [and liked it] in Belgium,” Sagan said.

Like the Super Six EVO and some high-end Cannondale mountain bike models, the Synapse Hi-Mod is built with BallisTec carbon fibers designed for military armoring covered by strategically placed and entirely interconnected strands of high- and ultra-high-modulus carbon fibers over the entire frame to give it stiffness in desired areas. The hot-cure resin and carbon layup are selected to absorb bump energy through “inter-laminar shear stress dissipation” (i.e., energy is absorbed in the shearing of the layers relative to each other). The twisted “helix” seatstays maximize the length of the fibers relative to the length of the stay to increase vibration dampening.

Full gallery of the Cannondale Synapse Hi-Mod >>

The flattened S.A.V.E. (Synapse Active Vibration Technology) shaping of the stays and fork legs, introduced in 2006 with the first Synapse, has been refined and is now called S.A.V.E. Plus, intended to provide more movement at the axles when the rider is either seated or standing. The helixed seatstays are designed to compress and twist a bit like a spring to let the dropouts move vertically more.

The fork is designed to also flex a bit inside the head tube as well as in the fork legs. This has been accomplished with a smaller tapered head tube, which goes from 1.25-inch (rather than 1.5-inch) tapering to 1.125-inch.

The 1-inch-diameter (25.4mm) seatpost is slim in order to provide more bump compliance, especially when a lot of seatpost is exposed. The collarless seat clamp shortens the top of the seat tube to increase the exposed seatpost length by 65mm. A vertical bolt tightens a wedge system against the front of the seatpost, and a bump in the crotch of the top tube/seat tube joint houses the wedge.

Finally, the most distinctive part of the frame is the seat tube; it has a cutout where it meets the bottom bracket. To allow it to bow, the seat tube is thin fore-aft near its base; this is carried over from the 2006 Synapse. Additionally, however, the “Power Pyramid” at the base of the seat tube is an asymmetrical offset split in the tube. Material has been removed from the long walls of the oval cross section and is instead concentrated into two more round pillars that meet the extra-wide (73mm) “BB30A” bottom bracket shell at its ends. By increasing the stance width, it becomes stiffer at opposing the torque on the bottom bracket shell from pedal forces with less weight, while maintaining the bowing flex of the seat tube over bumps and in response to rider weight on it.

The bike comes in 11 distinct sizes — six for men, five for women, including a 56cm women’s size — with three different fork rakes, depending on the frame size.

The Cannondale pro team requested the bike for the spring classics, “and of course we said yes, even though it was not ideal in terms of a marketing launch of the product,” U.S. road marketing manager Murray Washburn said. Willing to bear the costs of making new molds for Sagan (as he is a sponsor’s dream), Cannondale built his Synapse Hi-Mods in custom sizing; the rest of the team rides on stock frames.

The Synapse Hi-Mod frame is about half a pound heavier than the Super Six EVO (950g vs. 720g), but it is considerably lighter than most other entries in the endurance road bike category. The 61cm, SRAM Red 22-equipped Synapse Hi-Mod I’m riding in Tuscany weighs in at 6.93kg with pedals — just barely UCI-legal!

Ted King also likes his Synapse Hi-Mod, and says he wanted one from the first time he saw a plastic model of it. “You can ‘take that left turn,’” he said, meaning that the bike tempts him to discover where an unknown dirt or otherwise bumpy road goes. He has the riding position he wants on it despite the head tube being 3cm taller than his EVO and the top tube about a centimeter shorter. Instead of a 90-degree stem with a spacer under it like he has on his EVO, he has a longer, down-angled stem with no spacer. “It looks cool,” he said, “because now I have a slammed stem.”

Sagan said the bike is comfortable on rough roads and it handles well on the bumps. He still likes the way it sprints, like when he is sprinting away from the group and holding on for a solo win.

“It was perfect when I won Ghent alone,” Sagan said.

I rode the bike on a 60-kilometer group ride on the course of l’Eroica today, and I would agree with him. It sprints great, yet it is quite comfortable given the conditions on the rough, potholed and sometimes washboard “strade bianche” (white roads, dirt roads) here in the hilly region of Chianti.