The Tarmac SL4 is a pure & unbridled race machine. It climbs effortlessly descends confidently & sprints ferociously. Its the lightest stiffest frame we make & it shows as soon as you push on the pedals. Bottom line youll be faster on this bike. Theres a reason its the weapon of choice for the Saxo-Tinkoff Astana & Omega Pharma-Quick-Step Pro Tour teams. Specialized SL4 FACT 10r carbon frame with uniquely shaped tapered headtube & OSBB is now even stiffer & lighter for pure unbridled speed & power Full monocoque FACT carbon fork with a tapered carbon steerer is super light with great torsional rigidity for high-speed handling Specialized Pro FACT carbon seatpost is super light & stiff for optimal power transfer during all-out seated efforts Technical Specifications FRAME Specialized SL4 FACT 10r carbon FACT construction tapered/shaped headtube compact race design 1-3/8" lower bearing OSBBFORK Specialized FACT carbon full monocoque OS race for 1-3/8" bearing hollow carbon dropouts HEADSET 1-1/8" upper & 1-3/8" lower stainless steel cartridge bearings 8mm carbon cone spacer w/ 20mm of carbon spacers SEATPOST Specialized Pro SL FACT carbon 2-bolt 27.2mm SEAT BINDER Forged alloy Ti bolt 32.6mm