Giant TCR Advanced SL 0 Disc review

The 2021 Giant TCR is the ninth iteration of the compact-framed race machine that debuted two decades ago, back in 1997. There is, however, nothing ‘nineties’ about this superbike.

At the heart of all the Advanced SL models is a new way of manufacturing carbon-fibre frames, which involves Giant weaving its own carbon-fibre sheets in-house to exacting specifications and cutting each piece used in the frame with highly accurate, laser-cutting tools.

That means over 500 precisely cut pieces make up the frame (compared to the previous model’s 380).

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There is also a new method used to bind it all together in the form of a carbon-nanotube infused resin that greatly strengthens the bond between the layers of carbon composite.

This is claimed to greatly increase impact strength and reduce weight. Weight reduction also comes from special thin-line paint, which saves 65g over Giant’s standard, seven-layer paint applications. It all adds up to a frame and fork that’s 140.43g lighter than the previous model.

Giant doesn’t make claims on frame weight, rather it gives the weight of a complete painted frameset (which means fork, headset, all metal hardware and seat clamp) as 1,266g. By comparison, the lightweight S-Works Tarmac weighs in at 1,371g. So, rest assured, the TCR is a very light bike.

The frame’s stiffness and aerodynamics have also been improved, which shows just how important the new Advanced carbon materials and manufacture have been to this bike’s design.

One of the unique features of the SL 0 is the use of an integrated seatpost (ISP). In the past we’ve heard complaints that an ISP means that your bike is hard to pack to travel. Well, I’ve taken a TCR with an ISP (cut to 79cm) on many flights in a Polaris box and Scicon case and had no trouble at all.

Id rather have a seatpost that has no chance of slipping or twisting from water ingress from riding on wet days and is lighter than a conventional set-up. And because the post transitions into the frame it’s more aerodynamic too.

My complete test bike, a large fitted with two Giant bottle cages, tips the scales at just 6.71kg. Consider that the UCI’s legal limit for racing is 6.8kg and that shows just how light this bike is.

On the road, I have to admit to being somewhat apprehensive about such a light bike. Surely it would put too much pressure on the stiffness and ride quality when it’s this minimal? Particularly because, at 92kg, I'm not exactly a featherweight ride.

However, I’ve been completely blown away by the dynamic feel of the 2021 TCR. You can’t detect any unwanted flex through the pedals and bars and the response of the ride is sheer brilliance. It shines very brightly when you’re powering on the pedals and the swiftness of the handling makes for a bike that can be flicked and thrown around in an instant. It simply refuses to be anything but spot on when it comes to handling; nothing knocks your confidence.

Any bike this light is going to climb with the best of them. As you’d expect, the TCR does it with a willingness to plough ahead in a straight line, aided in no doubt by the lightweight 1,327g CADEX 42 wheels keeping all important rotating weight to a minimum.

When tested independently on an old TCR, CADEX were found to be among the best-balanced wheels in terms of rigidity, speed and comfort. On exiting a lean after cornering, they just seem to want to stand up straight and get on with the business of getting you down the road.

The addition of aerodynamics to the TCR frame have wind-tunnel figures to back them up and the subtle, truncated airfoil shapes of the tubes give the new TCR all the aero kudos of a cutting-edge bike. Giant claims that testing of the frame and its new aerodynamic features will save you 34 seconds over 25 miles (40km).

At odds with this are the short sections of external hoses on both front and rear brakes, rather than the fully integrated routing of rival bikes. It may save a watt or two to go internal, but I like that Giant has retained simplicity in the cockpit, which also deserves praise.

The stem is an elegant, matt-finished carbon unit, which is all good, but the new Contact SLR bar is the real star of the show following the same clever design principles as the Defy’s superb hand-holds.

Great shape, impeccable vibration reduction and ergonomically shaped tube profiles in the drops and on the tops: make no mistake the TCR is at its heart a race machine where lightness and stiffness take priority over comfort.

It’s not an uncomfortable bike, though, thanks to the bar, D-Fuse-shaped ISP and excellent short-dimension Fleet SLR saddle, yet it still communicates the feel of the road, grip-wise.

The 25c tubeless tyres are supple and grip for days in dry conditions, but I tried switching out the wheels for a pair shod with 28mm tubeless tyres and the difference is marked.

Racier types may turn their noses up at 28mm tyres for not communicating the road surface efficiently, but when those surfaces aren’t ‘race enough’, I’d always opt for more volume, cushioning and less fatigue even if this means a few extra grams.

The bike’s basic geometry hasn’t changed over the outgoing model. There are small changes: a 2mm reduction in the bottom bracket height to allow for increased tyre capacity (the 2021 bike will take 32c tyres, the old one up to 28s), the stack height from the bottom bracket remains the same at 581mm (L) and the reach is 402mm making it race focused: long, low and fully aggressive. Parallel 73-degree angles for head and seat are classic race-bike stuff too.

The Red AXS gearing is 48/35 with a 10-28 cassette and 12 speeds. That’s the equivalent of a 52/36 with an 11-28 on a traditional 11-speed setup but with a slightly lighter gear and a higher gear at each end.

Red AXS’s simplicity of operation is welcome, as is the adjustability through its accompanying app, which also reads from the included Quarq power meter. At the end of each ride it’ll report on the number of shifts, power max, average and normalised power, along with a full GPS track of your ride (Garmin or Wahoo).

The info syncs to your head unit, which will then auto-upload to Strava. Or you can link directly to your GPS head unit and show battery levels, gearing, cadence and all of the power metrics supplied by the Quarq. SRAM’s new brake rotors and the flat-mount Red hydraulic units provide consistent powerful braking that are full of feel.

This latest TCR only enhances the reputation of a bike that, for more than two decades, has been at the forefront of race-bike design and performance.

Giant TCR Advanced SL0 Disc geometry