Swanson wasn’t worried about pedalling stiffness, the feature that keeps the bottom bracket from budging when you add power. “Once you get past a certain point, it does not matter because people are only so strong. Once you get above the 65 N/mm, it doesn’t matter anymore. For example, the Giant [Defy Advanced SL] is at 70, and the [Specialized] S-Works [Roubaix SL4 Disc] is at 67. You’ll never be able to tell the difference. This bike could be at 95, that one could be at 150. Again, you’ll never tell.”
The new Defy Advanced SL and Avail Advanced SL flagships blur the lines even further between what many riders might expect from a 'race bike' and a so-called 'endurance bike'. The more sharply engineering-centric frame shapes are still less than 900g – a number many dedicated competition frames struggle to hit – and yet Giant also claims that they're more comfortable than their previous versions.
Key ride-oriented features include seat tubes, and top tubes that are supposedly more apt to flex over bumps than rounder sections; similarly D-shaped seatmasts and seatposts with slim diameters and lots of extension; lowered seat stays that are said to act more like leaf springs than conventional rear-end layouts; and slender fork blades that balance out the ride from front to back.
The feature of an endurance frame that seems to sit at odds to stiffness is compliance. You want some vertical compliance in frame to minimize the transmission of road vibrations to the rider. These high-frequency vibrations can wear you down on long rides. To manage these vibrations, the Defy borrows an innovation from the 2014 TCX, one of Giant’s cyclocross bikes. The D-Fuse seatpost, with its D-shape cross-section, debuted on the TCX. However, it was designed for the Defy. Swanson and his team wanted to see how the D-Fuse would perform in extreme riding conditions before they put it on the endurance machine.
On the Defy Advanced SL, the D-Fuse is used with an integrated seatpost (ISP). Its shape allows for noticeable flex fore and aft, but almost no movement side to side. The seatstays of the Defy have a low angle, so they meet the seat tube below the top tube. This junction helps to dissipate road vibrations, which take the path of least resistance up a frame. On a frame with seatstays that meet the seat tube and top tube higher up, the vibrations are channelled mostly up the seatpost. On the Defy, they are diverted more to the top and seat tubes. Finally, there’s the front fork. Its beefy fork crown works to provide front-end stiffness, while its thinner, curved legs add to compliance.
While all of the Defy and Avail models are brand new, geometry is wholly carried over – a good thing since they were already highly refined with stable manners and modestly raised front end that's just 15mm taller on average. Giant has taken the bold step, however, of exclusively using disc brakes nearly across the board for more consistently predictable all-weather stopping performance.
All carbon models will be disc-equipped for 2015; aluminum bikes will all be rim brake-only. Impressively, Giant looks to have done this without adding any weight – and in fact, says certain complete bikes even end up about 50g lighter than their comparable rim brake-equipped versions. We measured a top-end Defy Advanced SL 0 model at just 7.3kg (16.1lb)
"Our goal was to have a net zero increase," said road product manager Jon Swanson.
Giant has not paired those disc brakes with thru-axles, though. According to Swanson, this was done so as to provide disc-equipped Defy and Avail owners with more wheel choices. Swanson also isn't satisfied with current thru-axle standards as they pertain to road bikes, saying they're overbuilt for the application and insufficiently elegant for the genre.
Officially, eliminating the rim brake calipers also yields easy clearance for tires up to 28mm-wide – although we think many 30mm ones will fit, too.
· Defy Advanced SL 0 (US$10,300): Shimano Dura-Ace Di2 drivetrain; Shimano R785 hydraulic Dual Control levers and brakes; Zipp 202 Disc carbon clincher wheels
· Defy Advanced SL 1 (US$4,950): Shimano Ultegra drivetrain; Shimano RS685 mechanical Dual Control levers and R685 hydraulic disc brakes; Giant P-SLR0 Disc carbon clincher wheels
· Defy Advanced Pro 0 (US$4,900): Shimano Ultegra Di2 drivetrain; Shimano R785 hydraulic Dual Control levers and brakes; Giant P-SL0 Disc aluminum clincher wheels
· Defy Advanced Pro 1 (US$3,500): Shimano Ultegra drivetrain; Shimano RS685 mechanical Dual Control levers and R685 hydraulic disc brakes; Giant P-SL0 Disc aluminum clincher wheels
· Defy Advanced 1 (US$2,600): Shimano Ultegra group; TRP Spyre mechanical disc brakes; Giant P-R2 Disc aluminum clincher wheels
· Defy Advanced 2 (US$2,075): Shimano 105/RS500 drivetrain and levers; TRP Spyre mechanical disc brakes; Giant P-R3 Disc aluminum clincher wheels
· Defy Advanced 3 (US$1,750): Shimano Tiagra group; TRP Spyre mechanical disc brakes; Giant S-R2 Disc aluminum clincher wheels
· Defy 1 (US$1,375): Shimano 105 group; FSA Gossamer Pro cranks; Tektro TK-R540 rim brakes; Giant P-R2 aluminum clincher wheels
· Defy 2 (US$1,075): Shimano Tiagra group; Tektro TK-R312 rim brakes; Giant S-R2 aluminum clincher wheels
· Defy 3 (US$950): Shimano Sora group; Tektro TK-R312 rim brakes; Giant S-R4 aluminum clincher wheels
· Defy 5 (US$620): Shimano Claris group; FSA Tempo cranks; Tektro TK-R312 rim brakes; Giant S-R2 aluminum clincher wheels
8850 Stockdale Hwy.
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