Specialized S-Works Tarmac SL8 Dura-Ace Di2

Specialized’s all-round race bike is now even lighter, but what else is new?

How does this latest model improve upon the already highly impressive Specialized S-Works Tarmac SL7? Well, while they’ve adopted a general “if it ain’t broke, don’t fix it” approach to the geometry, there have been a few tweaks to the frame’s make-up to make the SL8 even faster and lighter…

Aero gains

The elongated headtube, or Speed Sniffer, is said to capture airflow sooner than the SL7 did for an aerodynamic gain. The latest Roval Rapide integrated cockpit also boosts efficiency by a claimed four watts at 45kph. The seat-tube and seatpost are both narrower, while the fork’s leading edges have also been re-shaped. All of this, say Specialized, makes it “16.6 seconds faster over 40km” than the SL7.

Light touch

Rounder shaping on the down-tube, seatstays, seat-tube and seatpost is inspired by the brand’s Aethos model, which prioritises light weight over aero gains. The rounder shapes use less carbon, reducing weight, plus improve through-the-saddle compliance (by a claimed 6% from the SL7). To balance this, the bottom bracket, head-tube and fork have been stiffened. A 12r Fact carbon frame, now a claimed 685g in a size 56cm (down from 800g), has a 33% better stiffness-to-weight ratio.

Stacked up

Geometry-wise, it’s very similar to the SL7, and set up for rapid handling and an aggressive riding position. Stack height has increased by 10mm, but this basically balances out once the updated cockpit and headset spacers are taken into account. Tyre clearance is still 32mm (measured).

Ace groupset

The Shimano Dura-Ace Di2 R9200 build is pro level, but with a 52/36t crankset here to better suit amateurs, paired with a 4iiii dual-sided power meter. You can opt for an identicallypriced Red eTap AXS version, with a SRAM Red AXS power meter instead.

Rolling stock

In-house brand Roval’s top-spec Rapide CLX II wheels have a 51mm-deep front rim, and a 60mm-deep rear rim, with 21mm internal widths. S-Works Turbo RapidAir 2BR tubeless-ready tyres are set up with butyl inner tubes.

“The SL8’s latest Roval Rapide cockpit boosts efficiency by a claimed four watts at45kph”

Bike as shown: Weight 6.76kg (size 56cm) Frame Fact 12r carbon Fork Fact 12r Carbon Gears Shimano Dura-Ace Di2 R9200 12×2 (11-30t, 52/36t) Brakes hydraulic disc Wheels Roval Rapide CLX II Finishing kit 15mm setback seatpost, Specialized Body Geometry S-Works Power saddle, 110mm stem, Roval Rapide carbon 40cm bar, Specialized S-Works Turbo 2BR 26c tyres with tubes, 4iiii Power Precision Pro power meter