Combing out of the same molds as the C5 is the Cervélo C3. Think of it as the same performance with more weight and less cost.
The differences in the two bikes are merely material. Less expensive carbon, a simpler lay-up means that the bike is priced better, but you get the same position, features, ride, and can hit all the same roads, trails, paths, whatever that you’d accomplish with the C5.
The C-series is newish for Cervélo. It’s their endurance bike line. Thanks to the demands of Paris-Roubaix, they’ve been going down this road for some time. Most famously, Johan Vansummeren rode a proto-C Cervélo R3 Mud to victory in Paris-Roubaix, the roughest of the cobblestone classics. That bike was modified from stock with longer stays and a longer fork, both to fit the 27mm tubulars the riders needed for the race, and to add essential comfort to make the interminable cobblestone sectors a little less savage.
The C3 starts with Cervélo’s standard 73-degree seat angle and Squoval tube shapes (think square, oval, and aerodynamic). They then build the bike with a more laid-back head angle, a fork with 10mm more rake, and 15mm longer stays. They also increase the bottom bracket drop, with the smaller sizes having 9.5mm more, the middle sizes, 7mm more, and the large sizes 4.5mm more. This improves stability, with a nod to keeping cornering clearance decent. Better than the R3 Mud, you can fit 28mm tires easily into this frame. Unlike that bike, this has disc brakes.
Cervélo incorporates Shimano’s Flat-Mount standard to attach the brakes to the frame. It’s a minimal design, light, and reliable. The mounts are positioned to work with rotors up to 160mm in diameter. To maximize strength, and minimize weight and complexity, they employ thru-axles, both front and rear. Thanks to the BBright bottom bracket standard, they’re able to keep the stays mounting point wide and offset the crank to deal with the 135mm rear hub spacing.
Thanks to the chainstay brake mounts, the rear end has been redesigned, with the seatstay, chainstay, and bottom bracket area molded in one piece. The seatstays are slightly bowed upward, the seatstay brake bridge removed in the name of adding compliance, and even the lower joining of the seatstays to the frame is done in the name of softening up the ride.
Another change made for the longer fork is a new lower headset race. Cervélo typically uses a tapered 1 1/8” to 1 3/8” steerer. Here, it’s 1 1/8” to 1 1/2”, to better deal with the stresses that the new fork adds.
The fork is a simpler version of the Project California fork found on the C5. Project California is where they test out their newest ideas. The C5’s fork is on the bleeding edge, and it takes incredible attention and time to build it. The C3 fork cuts it a bit wider, with a simpler build process, more strength, and less time.
The C5 comes with Future-Proof Cable Management, meaning that the routing is internal and accommodates both mechanical and electronic shifting. For electronic shifting, the battery goes in the included seatpost. For mechanical, the shifting is smooth thanks to the reduced friction bottom bracket cable guide.