First Look and Ride: 2015 Giant Defy endurance road bike line

Disc Road Bike

2015 Giant Defy Endurance Bike

The top-of-the-line Defy Advanced SL 0 comes stock with Shimano Dura-Ace Di2 and Zipp 202 Disc carbon clinchers.

Giant has made a giant-sized statement. Last week at a press event in Scotland, the world’s largest bike maker rolled out a fully revamped version of its Defy endurance road bike, claiming it’s both the lightest road frame it’s ever produced (890 grams for size medium Advanced SL), and that it smoked comparable competition when lab tested for weight, stiffness and compliance (more details below).

Perhaps more significant is that Giant is going all in with disc brakes, outfitting all eight carbon fiber 2015 Defy models with the burgeoning road braking standard. Top of that line is the wallet-busting Defy Advanced SL 0, which comes stock with Shimano Dura-Ace Di2 shifting, Zipp 202 Disc carbon clinchers, and a $10,300 price tag. If you want traditional rim brakes (and/or to spend a whole lot less money) you’ll need to choose from one of five lower-tier alloy models.

The development project started with a basic goal: make a Defy with disc brakes, but add no weight and strike the coveted balance between stiffness and compliance. “This was a purely engineering driven project,” said Jon Swanson, Giant’s global road category manager. “There are no gimmicks and no fluff. The only thing that did not change between the new Defy and its predecessor was the geometry.”

2015 Giant Defy Endurance Bike

An overlay of the old under the new Defy shows that geometry indeed remains all but unchanged.

Swanson’s knock on “gimmicks” was clearly aimed at the competition, many of which use various add-in bump-absorbing technologies in their endurance road frames; see Zertz (Specialized Roubaix) and IsoSpeed Decoupler (Trek Domane) for examples. “It’s not easy to make a frame without stuff in it,” added Swanson. “I had to fight to not just add something in so we can show a picture in a magazine.”

Instead, Swanson and his team claim to have increased compliance primarily through the use of the D-Fuse integrated seatpost in the two Advanced SL models, a design originally used in Giant’s top end TCX cyclocross bikes. The thin D-shaped post is claimed to add 12mm of ride-smoothing flex, but have no effect on power transfer. Once cut, there is 25mm of adjustment, which Giant feels is adequate to alleviate concerns about resale, a common complaint leveled at integrated post designs. However, that doesn’t solve potential problems of travel or test rides.

2015 Giant Defy Endurance Bike 2015 Giant Defy Endurance Bike

The new Defy uses two forms of its ride smoothing D-Fuse seatpost. Top end SL models utilize an integrated set-up, while mid-tier bikes have an integrated seat clamp.

The rest of the composite frame models use a more traditional seatpost binder that has an expander bolt easily be accessed at the top tube. Swanson says the ride characteristic of the two systems will vary some, and the non-integrated posts are less stiff and a little heavier.

All the new frames also utilize dramatically thinned compliance-enhancing seat stays, which attach lower on the seat tube. Ride feel is further enhanced by the stock 25c tires, and Swanson says 28s are no problem.

“The stays are basically as thin as we can possibly make them while keeping them hollow,” explained Swanson of the leaf spring design. “By keeping the stays hollow and eliminating the need for a brake bridge, we get vertical compliance without sacrificing stiffness. Lowering the junction point gives the frame balance. The upper half of the bike is compliant, the lower half maintains stiffness.”

Check out the video below to see the integrated seatpost in action.

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Weight was also a huge design driver. Swanson says the top end frame is the lightest road frame Giant has ever produced. “The perception is that with road disc you have to pay a weight penalty,” said Swanson. “We approached it as how do we offset that weight. And we actually dropped 50 grams on our top end frames, which is pretty significant when you see our competition having to add 40-50 grams to get disc tabs on.”

That weight was shed in part by using hollowed carbon dropouts, eliminating the brake bridge, and generally minimizing the need for reinforcement frame material by reducing the number of holes in the carbon frame. The front brake hose is routed externally; all other cables/hoses go into one side of the frame because when you punch a hole in frame you have to add weight with reinforcing material. Instead Giant made a single slightly larger hole on the non-driveside.

“That’s where having our own factory is huge,” said Swanson. “From conception to in-house engineering to design to development to prototyping, all the way through manufacturing, it’s all completely in house and completely controlled by Giant. The only thing we get from the outside is raw carbon fiber. We sit in offices above factory floor and if there is a problem or question, we can simply walk down a flight of stairs and are right in front of it. That level of control is huge and we feel it’s a massive advantage over everyone else. Nobody else has that level of control.”

Giant also opted for traditional quick releases rather than thru-axles. Swanson said this was both a weight saving measure, and a nod to the wait-and-see approach the company is taking toward the increasing use of disc brakes on road bikes, but the lack of an established standard when it comes to axles.

“People will say that once in a while you can get your rim brakes to hit your wheel so wont the same thing happen with rotors,” explained Swanson. “But that’s a wheel issue, not the core axle assembly. When there is an industry standard that goes beyond a couple third party players, and there are the same tolerances with the same designs, then we’ll go with that. But at this point I was not comfortable building a product that would lock someone in to a limited number of wheels.”

2015 Giant Defy Endurance Bike 2015 Giant Defy Endurance Bike

Bikes come stock with 25c tires (pictured) and are rated for 28c max. But you might be able to sneak a 30 in there. The headtube and fork integrate nicely.

Swanson did admit that moving to a thru-axle would have allowed for less material in the fork, and speculated that eventually 12mm will become the industry standard.

“Right now there are multiple conversations happening between a few of the big brands and everyone is talking the same talk,” he said. “If it was up to me it would be done by now. But we still need the collaboration of the big brands to come together. I think 12mm is a good number. It’s a number that gives enough stiffness that you can remove material from the fork leg, and I think 12mm thru-axles can be made light and still be stiff. But no matter where we end up, it also needs to have true quick release functionality so you can get wheels on and off quickly.”

In an attempt to validate all the highlights of the new Defy, Giant says it conducted a series of comparative tests, focusing on weight, stiffness and compliance. The test field included the new Defy Advanced SL frame, along with Cannondale’s Synapse Hi-MOD Disc, the Specialized S-Works Roubaix SL4 Disc, and Trek’s Domane 6 Disc. Not surprisingly, the information shared painted Giant in glowing light.

Weight comparison was based on size medium/56cm production frames with fork, headset, derailleur hangers and seatpost/ISP. Stiffness was tested by fixing the rear drop-out, then measuring how much force it took to move the frame. Pedaling stiffness looked at force put into the bottom bracket with front end fixed and the rear end placed in a dummy hub. Bikes were then leaned at an angle representative of sprinting to measure how much force it took to deflect the bottom bracket side to side.

Finally, Giant looked at compliance, using methods created by a third-party auto/motorcycle tester. This pair of tests measured the amount and effect of vibration transmitted to a rider’s hands, and the force coming through the saddle. Giant, as illustrated in these four screenshots displayed during the press launch, claims it topped the weight and stiffness comparisons, and was the second most compliant behind Cannondale’s Synapse Hi-MOD Disc.

2015 Giant Defy Endurance BikeWeight comparisons used size medium, painted and decaled production frames.

2015 Giant Defy Endurance BikeIn the compliance test, framesets were locked at the fork dropouts, held loosely at the rear dropouts, and then force was applied to a dummy crank. The mower the number, the more compliant, says Giant.

2015 Giant Defy Endurance BikeTest results were based on scenario where framesets were locked at the rear dropouts and side force was applied to the fork dropouts, simulating cornering and sprinting. The higher the number, the stiffer the bike claims Giant.

So who is this bike for? Swanson believes most people should be riding bikes like the new Defy. And generally speaking, we agree. Unless you’re Captain Criterium Racer, endurance road bikes simply make more sense. “It’s great for Giant to sell lots of Propel (aero road bikes) and TCR (race bikes),” added Swanson. “But if you look at people’s position on those bike, you end up seeing a lot of spacers and flipped stems being used. With the Defy, people can really benefit from the geometry, and that’s even more true now that you get the performance without compromising stiffness.”

Head to page 2 to find read our first ride impressions, and see page 3 for a full breakdown of the line along with pricing and an extended photo gallery.

Also check back later this week for details on the all new Liv Avail women’s endurance road bike line, along with highlights of Giant’s new disc wheels and apparel.

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About the author: Jason Sumner

An avid cyclist, Jason Sumner has been writing about two-wheeled pursuits of all kinds since 1999. He’s covered the Tour de France, the Olympic Games, and dozens of other international cycling events. He also likes to throw himself into the fray, penning first-person accounts of cycling adventures in British Columbia, Belgium, Brazil, Costa Rica, France, and Peru among many others. Sumner, who joined the RoadBikeReview.com / Mtbr.com staff in January, 2013, has also done extensive gear testing and edited a book on cycling tips. When not writing or riding, the native Coloradoan can be found enjoying the great outdoors with his wife Lisa.


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  • sean fullerton says:

    Another overpriced over specked carbon bike..most amateur riders will never need a bike like this…get real guys…

    • sherwin says:

      might be over priced and too much of a bike for amatuer riders. Its not about need. This is about WANT. Who really needs a Porshe or Ferrari? People get the Ferrari/Porshe because they want one and they can afford one. Again is not about need for the non-Pro.

    • Darwin says:

      Need? Whats “need” got to do with it? Should everyone ride a bargain basement bike because you think thats all they “need”.?

  • jim Taylor says:

    I wonder how you fit this bike in a bag so that you can fly to a destination? The fixed seatpost would not fit in my current bike case

  • Mpz says:

    To fit it in a bike case I just take the crank off on my Time rxrs. It fits perfect like that.

  • Thorsten says:

    In deed I’ll never need this bike..
    got a bus-station in front of the door – I could take public transport…

    Or wait – I don’t even need the bus… I could work from home-office and order junk-food for delivery… I don’t even need to leave the house!

    But besides that “needs” – I WANT a Defy Advanced Pro with Ultegra Di2 and I will leave the house to ride my bikes.

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