Specialized is on a roll with single-bike launches this year. First there was the Venge + McLaren aero road bike, now the Tarmac gets a complete overhaul with the new SL4 model and (sshhhhh) there’s a new gravity rig coming in a couple weeks.
Taking over the top of the heap, the new 2012 Specialized Tarmac SL4 is what you’ll see Contador, Porte, Vino, Kreuziger, Van Garderen and Martin will be riding in the 2011 Tour de France. The frame has been reworked to drop weight and improve both torsional and lateral rigidity by going with a one-piece bottom bracket section, widening the seatstay’s stance and modifying their King Cobra headtube, among other tweaks.
Make the jump for all the goods…
Compared to the SL3, both use their FACT 11R carbon fiber, but the new Tarmac SL4 boasts a 19% better stiffness to weight ratio and 16% improvement in overall stiffness, all while dropping the total frame module weight.
The system weight for the frame, fork, S-Works crankset and headset is just 1995g (4.4lbs).
Starting at the front, weight savings start with the headtube. It uses their King Cobra shaping, but actually decreases the taper size from the SL3. By wrapping the oversized top- and downtubes further around the sides of the headtube, they were able to reduce the amount of material while stiffening it enough to drop to a 1-3/8″ lower bearing (from 1-1/2″ on SL3), which reduces the overall size of the headtube and sheds grams.
The bottom bracket shell and chainstays are molded as one piece, running seamlessly from the BB to the dropouts, which saves weight and improves torsional stiffness under power. The rear dropouts are hollow carbon fiber, but they’ve got steel inserts co-molded into them to protect the carbon during wheel changes.
Gratuitous carbon fiber construction shot. Mmmmmm…sexy.
The fork also gets hollow carbon fiber dropouts, and the new fork is 10% lighter than the previous model.
While some frames run only the shift cables internally, Specialized’s new Tarmac SL4 runs both shift cables through the downtube, with the rear continuing on through the chainstay, and the rear brake cable hides inside the top tube.
The seatstays were spread wider to join on the outsides of the seat tube. Specialized says they used “dual taper” shaping near the brake bridge to make it stiffer and improve braking performance. The dropouts are designed to allow the rear shift cable (or wire!) to run through it from the chainstay and pop out the back of the seatstay.
Yep, there’s a Di2 model. We’re working on details for this, whether it’s a separate frame from the mechanical, and also waiting on complete bike and frame-only weights and U.S. retail pricing. Will update as we get it.