At road.cc every product is thoroughly tested for as long as it takes to get a proper insight into how well it works. Our reviewers are experienced cyclists that we trust to be objective. While we strive to ensure that opinions expressed are backed up by facts, reviews are by their nature an informed opinion, not a definitive verdict. We don't intentionally try to break anything (except locks) but we do try to look for weak points in any design. The overall score is not just an average of the other scores: it reflects both a product's function and value – with value determined by how a product compares with items of similar spec, quality, and price.
Good scores are more common than bad, because fortunately good products are more common than bad.
First introduced in 2008, the Giant Defy needs little introduction; it's one of the most popular bikes in the endurance and sportive sector, and is the company's best-selling model, combining smart geometry with a full range of competitively priced builds. It's been completely revamped for 2015 with a whole new frame design providing enhanced comfort and, for the carbon frames, disc brakes only.
The fundamental changes to the new Defy are the wholesale switch to disc brakes for the carbon Defy models (the aluminium models stick with rim brakes), along with an emphasis on increasing the ride comfort through a reengineered carbon frame. They've retained the geometry though, which was one of the Defy's best qualities.
We're seeing more disc brakes on road bikes but Giant are the first of the big brands to commit to disc brakes on such a big scale as this. There really is no going back. Fortunately the new Defy with disc brakes is such a good bike that we reckon most customers will be happily won over. There might be a few issues to iron out, but on the whole disc brakes represent a massive leap forward in road bike development. It's not the future, it's now.
With a frame redesigned from the ground up with disc brakes a key feature, Giant have trimmed the weight down to under 900g weight for a size medium. Along with the reduced weight and focus on disc brakes, the other big area Giant have worked on developing is the comfort. And it's a whopping step forward: this really is an extremely smooth bike.
They've achieved this improvement by working on the carbon fibre layup and developing tube profiles and shapes, and on this top-end model the D-Fuse integrated seatmast, which has resulted in a claimed 11mm of deflection. That they've achieved this with no in-frame features like elastomer dampers is impressive, and the result on the road is one of a taut smoothness.
It's not as soft at the back as the Trek Domane, but it feels better balanced in the fork and rear-end, doing enough to smooth off the ugly edges of imperfections in the road surface like cracks and holes. It strikes a good balance between the outright stiffness of a race bike and the wallowy softness of some endurance bikes. There's a noticeable increase in frame stiffness when you're putting a load of watts through the cranks compared to other endurance bikes. In fact I found myself instead comparing the Defy to race bikes in this respect.
Integrated seatmasts have their detractors, so it's only the top-end models that feature them. Lower down the range are regular seatposts, made with the same profile tube as the seatmast. The seatmast clamp houses the Di2 internal battery and provides a wide range of vertical and fore-aft adjustment.
There are no thru-axles here, but rather conventional quick releases. Giant decided there wasn't a suitable road-specific thru-axle standard and there are simply more disc road wheels available with regular axles at present. Meanwhile, other manufacturers are simply using existing, and in Giant's view over the top, mountain bike thru-axles.
It's a pragmatic choice certainly. The majority of new disc-equipped road bikes are sticking with quick release axles, and after testing the Defy it's certainly hard to make a case for thru-axles. The axle debate is one that is sure to rage on, but for now Giant have been prudent.
The Defy range starts at £499 for the aluminium bikes, but the the carbon disc range starts at £1,199. The Defy Advanced SL 0 tested here costs a whopping £7,999 and is loaded with all the short of top-end kit you'd want on a bike if you won the lottery. It's not the sort of bike Giant expect to sell many of, but as a hero product, it doesn't half look the business.
At 7.29kg (16.07lb) it's the lightest disc-equipped road bike we've ever tested thanks to components like Zipp 202 wheels, Dura-Ace Di2 with R785 hydraulic disc brakes, Giant's own carbon fibre handlebar and oversized stem, Fizik saddle and Giant's own 25mm tyres.
However, before you head straight to the comments to register your complaint at that price tag, let me tell you the Defy Advanced 3 costs a more wallet-friendly £1,199 with what is essentially the same frame, but with a regular seatpost in place of the integrated seatmast, and a Tiagra groupset with TRP Spyre brakes.
Costing £2,599 the Defy Advanced Pro 1 is probably the pick of the range. It has the same Shimano Ultegra mechanical groupset and RS685 hydraulic disc brakes as the Cannondale Synapse Disc we're also testing at the moment, and you also get 30mm carbon fibre rims on the Giant brand wheels.
The ride is absolutely stunning. In this 7.29kg superbike build, the Defy Advanced is a very special bike. The performance feels like a racing bike with responsive handling but its main strength is how stable and and balanced it is. It manages to offer the sort of performance you'd demand of a race bike but with the longer wheelbase producing a wonderful planted feel at any speed, and especially through the faster corners. It's a race bike you can ride comfortably all day.
The frame isn't as compliant as some bikes in this category. Giant have struck a balance that places it somewhere between the outright stiffness of a race bike and the softness of an endurance bike. It's not as comforting as the Trek Domane but it offers a better balance of compliance through the frame and fork, with a crisper ride that is ultimately more rewarding when pushing on.
It's firm then, but most definitely not harsh. Not at all. It skims the top of spiky roads, smothers imperfections and dilutes bumpy surfaces like no other. It relays a decent amount of road surface through the controls, doesn't isolate you from the action, keeping you in constant contact with what it passing underneath the tyres, and allowing you to exploit the available grip of the tyres, especially on descents.
And there is no lack of speed with the Defy. It may have a more relaxed geometry than a race bike, but at times it feels just as rapid as one, with the Zipp 202 wheels imparting a great sense of momentum and acceleration when you need it. You can make startling progress on the Defy. I didn't feel any compromise in pure outright speed.
I know the quick release axle decision will upset some people, but I didn't detect a hint of flex in the frame or fork when sprinting or climbing out of the saddle. In fact, during my time on the bike, I didn't find myself questioning the choice of quick release over thru-axles. Depending on who you speak to, it looks like the future does signal thru-axles for road bikes, but right now the quick releases on the Defy are no cause for concern.
The geometry - and therefore handling and fit - is identical to the previous Defy, so anyone wanting to upgrade from an older Defy will know what to expect: a very well balanced bike with a comfortable position easily achieved. I tested a size M/L with a 56cm top tube, 18.5cm head tube, 100.7cm wheelbase, 42cm chainstays and 72.5 degree head and 73 degree seat angle. Those numbers add up to a bike that is as comfortable on longer rides as the Cannondale Synapse or Bianchi Infinito, with a good amount of reach to the bars to get a good stretch, while the taller head tube places the bars at a position that won't put too much strain on your back and neck.
The parts package on this top-end Defy caused no complaints. The R785 disc brakes are superb, and mated to TRP 140mm rotors front and rear provided more than adequate braking performance with no fade, squeal or binding through the test period, run in a full range of weather conditions. The Shimano Di2 groupset was faultless, the Fizik Aliante saddle comfortable and the Giant carbon Contact SLR handlebar a pleasing shape. The Contact SLR stem is a brute to behold but certainly beefs up the front-end steering no end.
The supreme balance of the Defy and agile handling when you push it harder makes for a dynamically exciting bike to ride.
The Defy was first introduced at a time when taller sportive and comfort-orientated road bikes were becoming really popular with cyclists who wanted a performance road bike, but a little more comfort than an out-and-out race bike offered. If you're a professional spending 30 hours in the saddle, a slammed front-end might be fine, but if you only ride 6 hours a week and mostly at weekends, such a position isn't very inviting. No wonder then that such bikes have gone on to be hugely popular, indeed they're the biggest selling bikes for many manufacturers, and there's now more choice than ever before.
This brand new Defy retains the geometry of the previous model but wraps it up with a smart looking new frame that is hugely more compliant and engaging to ride, with easily exploitable speed and genius all-day comfort. The disc brakes are fantastic, offer so many benefits over regular brakes and I applaud Giant in their bold decision.
The £7,999 price tag of this range-topping show stealer Advanced SL 0 is insane, but don't focus on the price and instead look further down the range where the more affordable models offer more or less the same frame but with a more competitively priced build. The £2.6k Defy Advanced Pro 1 looks like the highlight of the range.
With this new Defy, Giant have raised the endurance bike bar and it's a serious rival to the Cannondale Synapse, Trek Domane Disc and Specialized Roubaix Disc. That's some choice and the Defy has to be on your shortlist. It's one hell of a bike and will have the other contenders in this hotly contested category looking over their shoulders.
Stunning performance, fabulously comfortable and responsive ride with superb disc brakes
If you're thinking of buying this product using a cashback deal why not use the road.cc Top Cashback page and get some top cashback while helping to support your favourite independent cycling website
Make and model: Giant Defy Advanced SL
Size tested: 55
State the frame and fork material and method of construction. List the components used to build up the bike.
There is no better road machine for long, demanding days in the saddle. Think centuries, sportive and rough roads. The frame is handcrafted with superlight, professional grade Advanced SL composite that's engineered with endurance geometry and optimized to deliver a smoother and faster ride. It features innovative technologies including disc brakes and the D-Fuse integrated seatpost to reduce road vibration. The oversized and tapered OverDrive 2 steerer tube boosts cornering precision. The MegaDrive downtube and PowerCore bottom bracket deliver precise handling and unmatched pedalling efficiency.
Tell us what the bike is for, and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about the bike?
Advanced SL-Grade Composite frame with Integrated Seatpost
Advanced SL-Grade Composite, Full-Composite fork with OverDrive 2 Steerer
Shimano Dura-Ace/R785 Di2 22 speed drievtrain
Shimano R785 hydraulic disc brakes
Zipp 202 Disc Fire Crest wheel set
Was the bike comfortable to ride? Tell us how you felt about the ride quality.
Absolutely yes, but not soft at all, quite taut and enough compliance to easily remove the harshness from any rough road surfaces you care to ride along.
Did the bike feel stiff in the right places? Did any part of the bike feel too stiff or too flexible?
Nice balance of stiffness, with high stiffness around the bottom bracket and head tube for sprinting and hard riding, but not enough to beat you up or compromise the comfort factor.
How did the bike transfer power? Did it feel efficient?
Yes as good as many race bikes.
Tell us some more about the handling. How did the bike feel overall? Did it do particular things well or badly?
Very stable handling and steering when pootling along, but comes alive when you punch up the speed.
Which components had the most effect (good or bad) on the bike's comfort? would you recommend any changes?
The Zipp 202 wheels and their very low weight impressed on the climbs and acceleration was impressive, eye-watering stuff.
The Zipp 202 wheels are a huge contributor to the high price tag.
Did you enjoy riding the bike? Yes.
Would you consider buying the bike? I'd have to win the lottery first.
Would you recommend the bike to a friend? Yes.
Anything further to say about the bike in conclusion?
The Zipp 202 wheels obviously contribute massively to the price tag of this super bike, but ignoring the price (there's a complete range of better value bikes beneath this model) the new Defy is a massive improvement with great comfort, stiffness, weight and superb disc brake performance.
Age: 31 Height: 180 Weight: 67
I usually ride: My best bike is:
I've been riding for: 10-20 years I ride: Every day I would class myself as: Expert
I regularly do the following types of riding: road racing, time trialling, cyclo cross, commuting, touring, mtb,
David worked on the road.cc tech team from 2012-2020. Previously he was editor of Bikemagic.com and before that staff writer at RCUK. He's a seasoned cyclist of all disciplines, from road to mountain biking, touring to cyclo-cross, he only wishes he had time to ride them all. He's mildly competitive, though he'll never admit it, and is a frequent road racer but is too lazy to do really well. He currently resides in the Cotswolds, and you can now find him over on his own YouTube channel David Arthur - Just Ride Bikes.