BMC’s new Granfondo GF01 is a trueSpring Classics road bike. It got third in this year’s Paris Roubaix, not a bad finish for it’s debut, and in a vote of confidence for the new design, all of the BMC team rode it there.
Bikes like this have to balance stiffness to maximize power transfer and feel confident in hard corners, yet be able to flex where needed to soak up the bumps. The rough road and cobble compliance isn’t just about comfort. Preventing all of the bumps from hitting the rider reduces fatigue. Jonas Müller, BMC’s lead engineer on the GF01 project, said it’s designed to do exactly that.
It’s positioned parallel to current offerings, not above or below the TeamMachine SLR01 or TimeMachine race and aero models. That means it’s fully intended to be a top level race bike, just one that might appeal to a broader range of riders. For example, even though it raced to a podium at the Hell of the North, BMC is targeting three non-racing groups with it, too: Long distance riders, newbies and women.
All three of these groups benefit from a more upright, comfortable position. The geometry and design are intended to instill confidence, offer good ergonomics and be comfortable on a variety of surfaces. They accomplished this with the aforementioned blend of stiffness and compliance and by using slightly longer chainstays, a slacker head angle and increased fork rake.
Lastly, BMC focused on making the bike easy to use by spec’ing tubeless-ready Easton wheels, durable Continental tires and an integrated chain catcher.
THE TECHNOLOGY
TCC, or Tuned Compliance Concept, was introduced with the SLR01 race bike on the seatstays, fork and seatpost. Müller says TCC is really about careful selection of materials and tube shapes. For the GF01, they had to balance where and how they applied it. Too much flex in the seatpost and you get too much change in pedaling position and a weird feel. Too much in the fork and you get sloppy, scary handling.
The solution was introducing Angle Compliance. Where a straight tube is very stiff under compression, putting a bend in it gave them flex only in the direction they wanted. The chainstays were angled up just in front of the dropouts, and the seatstays meet the seat tube lower on the frame. The result is up to 16mm of deflection saddle and 4mm at the rear axle with all else static and deformation occurring in the seatstays and seat tube.
On both the fork and the chainstays, the sharp bend in the frames act as pivots.
The seatpost is also designed into the TCC concept. Their sloping top tube frame requires a longer post, which helps improve comfort from the get go. They worked on the layup of the post to balance flex with strength – remember, too much flex here can affect pedaling efficiency. The design is specifically built around the particular offset of the post, and three are offered: 3mm, 18mm and 30mm. Bikes and framesets come standard with the 18mm offset, others are available aftermarket.
For stiffness, the front of the top tube through the headtube, downtube, BB and chainstays until the bend, are part of the stable core of the bike and are made up of massive cross section tubes. In person, the downtube and chainstays are big. Really, really big.
Perhaps the best proof of the balancing act BMC pulled off with the GranFondo01 is that it’s both the stiffest and most compliant bike they made. The SLR01 beats it out in weight and aerodynamics by a small margin, but the GF01 is 40% more compliant and about 30% stiffer torsionally and laterally.
FIT & DESIGN
Stack and reach was kept at a 1.5 ratio across the entire size range. Müller said the idea is that the bike should fit the same way regardless of how tall the rider is. “You don’t want to change the fit just because the size changes. It’s not that 1.5 to 1 is the particular ratio that matters, it just worked out to provide the right fit. The stack is measured from a horizontal line at the BB center to the top of the headtube. Reach is center of BB measured horizontally to the same spot.
The brake caliper positioning was another matter of careful design. They found they could get a big tire into a standard road brake caliper if the pads were positioned just right. It worked out, and they’re able to get the 28C Continental into regular Ultegra brakes. Müller says the wider tires actually roll better than narrower tires and can run lower pressures for better comfort and traction. Multiplying that effect is the Easton tubeless ready wheels, which are wide and give more air volume to the package. In fact, they’re recommending running the tires between 80 and 90psi.
Why not spec road tubeless tires? Because there aren’t any 28C wide tubeless tires. Müller says they’d love to if they were available.
The bottom bracket is Pressfit86 because they’re mainly spec’ing Shimano cranksets, and that’s what their team is sponsored with. If they did BB30 or PFBB30, they’d have to find adapters, which would add about 60g according to their marketing director, and because it offers the right width to make the power transfer section of the bike very stiff.
Where the lower tubes are massive, the upper ones are minimal. Above, thin, flat seatstays flex when appropriate and below, the top tube tapers thinner as it nears the seat tube, which should help clearance for those (like me) whose knees tend to angle inward when pedaling.
The complete bike is only being offered in one spec (see below) with a retail price of $6,599 and will be available in June. They wanted to launch with a bike built the way they want it, so this launch build is their ideal of a Gran Fondo style bike. Key dealers should have a demo bike in house shortly after Sea Otter if your’e interested in trying one out. This is a 2013 model, so it’s really just an early release of this particular model with a frameset and other trim levels coming in the future.
The complete bike weighs in at a claimed 7.38kg (16.27lbs) with Fizik saddle, Ultegra Di2 group and Easton EA70 bar and stem. That’s for a size 54, and that size frame comes in at a claimed 995g and 380g for the fork. Six sizes available: 48, 51, 54, 56, 58, 61. (The bike above is a 54 and came in at 16lbs 9oz, just slightly more than claimed weight but includes a bottle cage. The only non-spec item on these bikes is the handlebar tape.
Assuming you wanted to drop some grams without blowing the bank, lighter saddles are available and you could swap in higher end Easton carbon bar and 90-series stem (or any other brand). That assumes you like the idea of the wheels and don’t want to splurge for Dura-Ace Di2. The short of it is this: You could get this bike a decent bit lighter without sacrificing the comfort aspects that BMC designed into it.
Should you want to build one up with a mechanical group, mounts are placed around the frame for cable stops, which will be included. Stock, it’ll have flush bolts in all of the mounting holes for a clean look.
