When we first spotted the new Calfee Manta Pro road bike on our Factory Tour, it was still in prototype form. Now, the design is final, and it gets some interesting tweaks to the frame and component spec.
Key changes include structural elements around the bottom bracket to change the flex point via stiffening struts. They also added more carbon material within the chainstays and where they meet the bottom bracket, as well as in the area around the suspension at the top of the seatstay wishbone under the brake caliper. That was done to reduce pedaling influence on the vertical flex and add strength to the system.
They also tweaked the cable entry at the front of the bike. The prototype had a gorgeous port letting the rear brake cable come into the front of the headtube. In practice, though, it wanted to turn the wheel a little, making it less stable when riding with hands off the bar. So, they moved it a bit further back.
Calfee’s known for their paint, too, and this show bike certainly didn’t disappoint.
The 65mm ID bottom bracket shell is designed around the Look ZED2 crankset. They did that to be able to fit a modified Campagnolo EPS battery into the downtube, and because the one-piece crankset is wicked light. They’re running Praxis chainrings. Note the color coordinated Look logo on the inside crank arm.
Now for the big change: Two struts are added to suspension models, connecting the BB shell to the chainstays, meeting about halfway toward the rear axle. The struts have 200,000 individual strands of carbon pulled through each stainless steel rod, with the metal there simply to protect the strands. Total added weight for both struts is just 35g, but they were critical to proper function of the bike. They stiffen the chainstays so the rear wheel remains in plane with the frame because the seatstay is not as much of a structural element once the suspension is added. The male end of the suspension is round, which reduced stiction versus a keyed or square design. But, leverage from the wheel could rotate it, and Calfee’s Michael Moore says the rear ended up feeling sluggish in the corners. Basically, the additional stiffness there had to make up for the suspension integrated into the seat stays.
Curious about whether the chainstays are really up to the task? They took a Cervelo with their infamously thin seatstays and massive chainstays and cut the seatstays off. They rode it and tested it, and it did just fine. That was the proof of concept that suggested stiffening up the chainstays would solve the problem…and it did.
So, why add struts rather than just beef up the chainstays? Because Calfee also offers a rigid Manta Pro, and the thinner stays on the rigid bike keep the ride quality smooth and comfortable. But the rigid bikes are retrofittable to the suspension model, so being able to simply add struts along with the suspension was the best overall solution.
They can also make it with disc brakes, and Moore says they’re building about 3:1 rim to disc brakes. They can even build it as a cyclocross or adventure bike. Aaaah, the beauty of custom. Wanna see all the options? Hit their website to kill some time. Retail starts at $4,795 for the frame, and $5,995 for the module with complete crankset, Chris King Inset 7 headset and Easton or ENVE tapered fork.
