Giant Propel Advanced SL 1 disc review

The latest Giant Propel is such an improvement on its previous aero bike that it has to be included. Its futuristic looks and great build quality makes it one of the better investments of 2018. It is also half the price of some of the other aero bikes on the market and if performance is everything to you then the Propel is the bike for you.

The new Giant Propel Advanced SL 1 disc is the latest aero racing bike from the brand. It isn't Giant's range topping model and sits one below, however, it has the exact same frame and fork as the higher end iteration, only differing in groupset and wheels.

Advanced SL-Grade Composite is Giant's highest grade carbon, woven within its home facility and manipulated using Giant's own process too, as all bike brands claim, to add stiffness and reduce weight. Giant continues to own its process by infusing the carbon with Carbon Nanotube Technology resin and says that helps improve impact resistance too.

Compared to the previous version of the Giant Propel this bike is completely different, redesigned from the ground up and wind tunnel tested to make what Giant says provides 'the ultimate winning edge'. It's called Giant's AeroSystem Shaping technology; look at the bike from the front on and you can really see how streamlined it is. Though I haven't got any data to back any of this up at the moment.

Much of my testing of this bike was in Mallorca as I spent the week trying to get myself into shape. Weather wise, it was amazing, as expected but some windy conditions made for tricky riding on a few days. The trip included mountains, flat roads, long fast descents and some sunbathing... One change I made, which doesn't effect the ride, was swapping the chainset for a standard 53/39 that included a Stages power meter.

A striking feature of the new bike is that rather large stem and handlebar combination. Despite what the images may portray, I've only got 15mm of spacers under that stem but it looks very high at the front, a notch in terms of looks which is a shame as the bike is rather striking and I like it.

The handlebar and stem isn't integrated, although only that combination will work together. All the cables are internal to the bars and in fact sit on top of the stem before diving into the frame behind it.

There is a top stem cover, which is what makes it look so high at the front. It hides all the hydraulic brake hoses and Shimano Ultegra Di2 cables. It is a tidy system and works well.

It isn't as scary to work on as you might think, four simple bolts hold the top plate in place and once removed you can remove the stem from the steerer as normal.

The half rubber half alloy spacers help keep the look clean but can be a little fiddly to work with, but it is far easier to tweak than say the Specialized Venge-Vias, you'll need a mechanic to come with you on your holiday for that to work. However, the four top bolts are rather fragile and are already starting to round out after a number of stem height adjustment and two bike bag de-rigs to Mallorca, something to keep an eye on.

Something to bear in mind when travelling with the Giant Propel Advanced SL 1 disc is that integrated seatpost. I'm a relatively small guy and have a saddle height of 73cm from the centre of the bottom bracket to the top of the saddle, and I can just about fit the frame into an Evoc bike bag and that was with the saddle off.

It meant that the seatpost was precariously vulnerable out on its own at the top of the bag and I fear that anyone with long levers will struggle to fit the bike into smaller bike bags or boxes.

For those of you that have been to Mallorca - which is most of the cycling population - you'll know that the roads are smooth and nice. Whilst I'd say that bike is very good in the comfort department, the integrated seatpost left me a little achy after an epic week on the bike.

I usually found day-to-day my rear not wanting to be in contact with the saddle after two to three hours. I changed out the Giant saddle provided for my usual Fizik Arione. The stiffness in the frame slowly wore me down and I ended up standing on the pedals to give myself a break from the road buzz felt via the integrated seatpost.

I won't go into detail of the groupset. Shimano Ultegrea Di2 is flawless, the hydraulic disc brakes were amazing and thanks to those slim hoods everything felt compact and in the right place. I was, however, a little frustrated to see that the 25mm tyres on this bike seemed to come up narrow on Giant's own SLR 1 Aero wheels.

It seems the wheels have a relatively narrow internal so the tyre tends to sit a little narrow too. Going up to 28mm tyres would have allowed for lower pressure and a little more give in the tyres especially in the bends - the frame has clearance for it for sure.

What I found was the frame itself is so stiff that it'll chatter, almost unnoticeably, around the bends. This doesn't mean it's dangerous or bad, but compared to a bike like the Cannondale SuperSix Hi-Mod Evo disc - which is a super machine at descending mainly as its compliance around corners allows for the tyres to remain in contact with the road at all times - the Giant just doesn't match up.

As I say it isn't bad and I wouldn't score it down compared to rivals like the Venge or even the Canyon Aeroad for that matter, but it is something to consider when purchasing a bike, is aero everything? You'll have a lot more fun on other bikes going down hill.

The Giant Propel Advanced SL 1 disc feels fast and runs along the flat incredibly well, almost without effort. Even on the climbs I was happy with the bike, it didn't slow me down in the slightest. However, on the descent down to Pollensa from Lluc monastery I just wished I was on my mates (more compliant) bike.

Despite the narrow nature of the the wheels I liked them. They rolled well and although I don't like the depth mix, 42mm front 65mm rear, they worked nicely. Giant set these up tubeless as well, ready to roll out of the shop.

Something I want to explore more is the balance of wheels when running tubeless, the rear in particular bounces, like an unbalanced wheel especially at high speed. It is a little unnerving at 70kmph. I wondered if this is because of the tubeless set up, with that relatively large tubeless valve on one side of the wheel. More investigation is needed and so I don't want to discredit the wheels.

As I say the frame is savagely stiff and that isn't all bad. Sprinting in particular is a joy as the bikes feels like a rocket ship when stamping down on the pedals. This'll be a mix of aerodynamic efficiency and raw stiffnes -  those large tubes, integrated posts, massive headtube and what Giant call its Powercore. A fully integrated, 86mm wide bottom bracket joins with asymmetric chainstays to provide all the stiffness you need, according to Giant and I'm in total agreement.

When all is said and done, I enjoyed my time with the Giant Propel Advanced SL disc. It is a super fast bike that'll give you all that you need in terms of performance. It is a little fiddly and the not best bike to travel with but it is far superior when compared to its aero rivals. The let down is rear end comfort but overall a far better bike than the previous Propel in my eyes.