Giant Defy Advanced SL1

Some bike reviews are based upon a two hour spin up and down a few hills and along a piece of flat road on a sunny Balearic Island. This is not one of those reviews.



Over the course of a number of months I have used this bike in many different ways. There is always the first impression factor but then I also used it in the snow and ice, over the cobblestones of Curraghmore Estate, on the greenway bike path with the kids, along a 10k overgrown riverbank and also for over 18 hours in a single day whilst climbing and descending over 9200 meters which is more than the height of Mount Everest. I also used the bike for a 1 hour Time Trial. In between I used it for every training spin, both solo and as part of a group. This is how I personally found the bike.



First Impressions

The bike looked nice but strange. Disc brakes on a road bike take time to get used to. The lack of brake calipers where they should be initially does not look right, but over time it sort of grows on you. The Giant P-SLR0 Disc Carbon wheels look good and with DT Swiss hubs at their core they work well too. Giants own brand Carbon SLR Bars and Overdrive stem look good and are both comfortable and stiff. A Fizik Aliante saddle which comes as standard is always a good choice for comfort. The Ultegra groupset needs very little to be said about it other than it works just as flawlessly as you would expect from Shimano. The weight of the complete bike in size L came in at just 7.5kg which is pretty light.

When riding a bike for the first time you are always more aware of the differences in it’s characteristics which become more muted over time, until you find yourself aboard a different machine.

My first day out on the Defy I headed for the hills above Clonmel. On the Mountain Road I noticed just how responsive the bike felt. There is a section where the gradient rises from 4 up to 7% for about 200 meters. Normally I change down a sprocket at the rear but on the Defy Advanced SL1 I was prompted to squeeze the pedals a little harder and there was no loss in momentum or speed.

Initially the bike also felt comfortable on the rough road surfaces of North County Waterford. I was sceptical about claims of the integrated D-Fuse seatpost which is supposed to absorb much of the road vibrations. Even though there was no actual moving part or suspension the bike does actually give a very plush ride.

The Hydraulic disc brakes were the most noticeable difference. Descending Powers the Pot to Harneys Cross is a good test of any braking system and I found myself being comfortable leaving it a little later than normal to brake whilst always feeling in control. The smoothness and light touch required to bring the bike to a non dramatic halt took very little time to adapt to. The biggest advantage of Hydraulic disc brakes is the ability to brake almost as well in the wet as in the dry.

Out of the saddle the bike felt lively, not in a Pro Sprinter kind of way but more like a controlled acceleration where you still feel as though all of your efforts are going in to propelling you forward.



Snow and Ice

As I was training for an Everesting challenge I needed to be prepared for all weather conditions. Climbing Tickincor and Powers the Pot as a blizzard took hold was ‘different’ and I had to try to position my weight evenly across the bike to avoid the rear wheel spinning out. This was not difficult to accomplish aboard the Defy Advanced SL1. On the way back down it became ‘interesting’ and at times I was right on the edge of my abilities to control the bike on very slippery corners. The disc brakes now became a revelation as they were always controlled and smooth. They never tried to ‘lock up’ which is a concern that I discovered to be unfounded.



Curraghmore Cobbles

Curraghmore Estate has been compared to the Strade Bianche and even Paris Roubaix. Sitting back over the rear triangle in a nice big gear, loosely gripping the tops of the bars I powered along in relative comfort. If a spoke was going to break this would be where it would happen. If the bike was going to leave me sore and weak this was the place to do it. Neither happened. Instead I always felt fully in control and as soon as I was back on ‘smooth’ tarmac, it was as if I had never even been in there. Another test passed with flying colours.




Cycling a greenway

One day I put on a pair of speedplay covers over my pedals and used the bike as high tech hybrid to cycle 10k with the kids. At their pace it was easy to manoeuvre and comfortable.

Another day I cycled the as yet undeveloped future greenway from Kilsheelan to Clonmel part of which is currently so overgrown that the grass was the height of the handlebars. I had to place my fingers behind the brake levers to avoid the levers snagging causing the brakes to engage sharply and jettison me into the river. Very few road bikes could cater as well under those conditions and I believed that the addition of a pair of cyclo cross tyres would make this a good cross bike.





Cycling the height of Everest

On May 30th I spent 18 hours and 15 minutes in constant contact with the bike. Starting at 5am I did not finish until 11.15pm that night. During that time I cycled 272km and climbed and descended over 9200 meters. For the last 6 hours a storm blew in and I had to draw on all of my reserves to make it to the finish. Whilst I had many pains throughout the day my lower back was never sore. This alone sold me on the D-Fuse system. It works. The brakes excelled. My hands never got sore or tired.  Descending, the bike felt like it was on train tracks all day long. It handles like a dream. It is so planted in corners that you always want to push on more. I had a spare pair of brake pads but still have not had to fit them. There are very few bikes out there, if any, that would have been a better choice for that effort on that day.

1 Hour Time Trial

Screenshot 2015-06-24 22.03.07


Two Weeks after the Everest Challenge I attempted ‘The Clonmel Hour’. A 6k ‘velodrome’ has been created on Strava where people ride as hard as they can for 1 hour to see how far they can go. Technically the Giant Defy Advanced SL1 is a Sportive bike. The Clonmel Hour had been attempted by a number of full kit TT Bikes with Aero wheels, helmets and Skinsuits. One hour before my effort the longest distance covered up to that date had been 38.4k. One hour later the Defy Advanced SL1 with no tri bars or any other addition had covered 39.4km. This bike is not just for riding sportives.


Overall this bike is very comfortable, handles really well, is responsive in a controlled manner, climbs like it has wings and is strong and reliable.



4 thoughts on “Giant Defy Advanced SL1

  • September 13, 2015 at 11:06 pm

    your review sounds great, i’m currently on a Defy 1 and ready for a composite frame. Thanks for helping me decide

    • September 14, 2015 at 3:59 pm

      I’m glad that you found the review helpful Jim. Best of luck with the new machine when you get it.

  • June 24, 2016 at 6:18 am

    Love the picture riding in the snow! You’re a serious cyclist. Converting kilos to pounds, it seems the Defy SL1 is 16.5 lbs., which is indeed light for a disc brake model. Is that correct?

  • July 1, 2017 at 3:33 am

    Very much enjoyed your review. Agree as to the pic of riding in the snow; “Anyone who does that is a little deranged!” But loved the pic and indicates your level commitment. I’m at the point where realize “Don’t have many years left” and would very much look to comfort as primary. And also like the idea that Giant is able to accomplish this without the addition of gimmicks. This is the best review of the bike to date that I’ve been able to locate.


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