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With a stealth black-on-black color scheme, Cannondale has camouflaged its most relaxed and versatile endurance bike.
The Synapse frame is a marvel of carbon fiber engineering. It is remarkably light at 950 grams. With the frame’s unusual split seat tube at the base, where it joins the bottom bracket, the bike feels particularly stiff under power. Yet the Synapse has impeccable manners when riding rough pavement, partly due to the flattened chain stays and seat stays. The skinny 25.4-millimeter seatpost also provides a fair amount of compliance in the rear.
If those frame design features aren’t enough for your bumpy rides, this frame is also capable of fitting up to 32-millimeter tires. That makes this one of the most capable endurance road bikes we’ve ridden. Plus, Cannondale snuck in some hidden fender mounts for those who live in wet climes.
The Synapse’s geometry and handling tilt toward the comfort end of the spectrum. Overall, the bike is a bit long with a 1,008-millimeter wheelbase. The 410-millimeter chain stays are conventional. So, the front-end geometry defines this bike’s personality. The Synapse’s slack 71.7-degree head tube is over a degree shallower than that of Cannondale’s race bike, the SuperSix Evo. Its stack is also 21 millimeters taller than the SuperSix.
All of this combines to put the rider in an upright position with muted steering. Along with the low bottom bracket (73-millimeter drop), the Synapse loves to cruise and isn’t afraid of fast dirt roads. The downside is that it is a bit uncooperative on twisty mountain descents and hairpin turns. You need to coerce the front end to follow the line. It feels a bit like you’re steering with the rear wheel.
Beyond the frame fundamentals, Cannondale chose excellent components for this Synapse. SRAM’s Red eTap HRD group remains the pinnacle of elegance in electronic shifting, without any shifting cables. The Synapse is built with a generous gear range on that drivetrain as well — compact 50/34-tooth chainrings and an 11-32 cassette.
Cannondale’s Hollowgram Si carbon clincher wheels were good but not exceptional. Their 19-millimeter inner width seemed a bit narrow. (Most rim manufacturers are going wider, often in the neighborhood of 21 millimeters.) We were pleased that these hoops came with Vittoria’s 28-millimeter Corsa tires with stylish tan sidewalls.
When it comes to looks, the Synapse is a crowd-pleaser. Nearly everyone can get behind the light weight, stiffness, and componentry as well. The geometry is the deciding factor. If you need an upright fit and like a bike with mild-mannered steering, the Synapse should be near the top of your list. But if you want fighter-jet handling for the miles of sinuous mountain roads in your backyard, this might not be the right ride.
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