Wilier Filante SLR 2021

The Wilier Filante is a lightweight aero road bike that offers a reactive performance, quick handling, and a surprisingly comfortable ride. If Wilier is to be believed, it's aerodynamically efficient across a range of real-world conditions too. Okay, the Filante should be pretty amazing given the price, but this one really is a bit special. Here's why...

First, the Filante's acceleration is really impressive. From a standing start, getting up to speed after a tight turn, or simply when you're trying to put some daylight between you and the rest of the bunch, you're rewarded with easy speed when you flick the pedals. Let's not over-egg it, but this bike feels taut and keen when you hit the power, rather than sloppy and reluctant. If someone tries to get the jump on you, they'd better have planned it well because the Filante is up for getting on their wheel in an instant.

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You definitely can't judge bikes on the scales, but when a disc brake bike in an XL size weighs just a whisker over 7kg – and Wilier claims a weight of 870g for the frame and 360g for the fork – you'd be mad not to take notice, especially when it's an aero bike.

A lightweight aero bike, you say? Or, if you flip your perspective, an aero lightweight bike? The latest versions of the Giant TCR, Trek Emonda and Specialized Tarmac all seek to combine aero efficiency and a light weight. It's the new black.

Aerodynamics is a tricky old thing. If you really want to know about it you have to take a bike to the wind tunnel, and that's neither cheap nor convenient. Failing that, you can listen to what the brand in question has to say and see whether you're convinced. So what does Wilier claim for the Filante?

> Lightweight vs aero…

Wilier uses truncated NACA (National Advisory Committee for Aeronautics) aerofoils for the Filante SLR's tube profiles, as it does for the Cento10Pro aero road bike. There's nothing unusual in that. Bike manufacturers are always taking an aerofoil shape and chopping the tail off so that the airflow behaves almost as if it's still there, while saving material and weight, and avoiding handling issues. It's standard practice. The difference, according to Wilier, is what it has done with the cutoff at the rear of the tube.

Wilier has softened that cut. Rather than being totally squared off, the edges are more round. It's not a gentle curve back there but it's not abrupt either.

What difference does it make? Wilier says that in the real world, where the wind comes from all directions, the boundary layer – the wind particles closest to the frame – adhere more to the profile than on the Cento10Pro. The idea is that as the yaw angle changes – yaw resulting from the bike/cyclist's direction and speed, and the wind angle and speed – the frame maintains good aero characteristics.

Wilier has also made the Filante SLR's fork legs wider than most – 7mm more than those of the Cento10Pro – and the rear triangle is similarly wide. Look from the front of the bike and you can see that the stays are completely hidden by the fork. Obviously, this isn't anything to do with making it look neat and tidy, it's all about how the tubing is presented to the wind, the aim being to reduce drag.

Wilier says that it tested the Filante SLR in the wind tunnel at yaw angles from +20° to -20° and that the new design results in significant aero improvements over the Cento10 Pro in real-world situations. However, it doesn't offer stats comparing the Filante with that bike or with rivals from other brands.

Granted, we always take those stats with a hefty pinch of salt anyway because, funnily enough, every brand's figures prove beyond doubt that their own bike is far and away the most efficient in the known universe. Definitely. But it would still be interesting to see Wilier's workings out and to know what 'significant' means in terms of the drag coefficient, watts or time saved. We asked, of course, but Wilier isn't up for sharing that info.

While we're talking about the tube shaping, Wilier says it's this more rounded profile at the rear that keeps the weight down. Less material is required than for a sharp cornered design, and it's apparently easier to avoid excess resin that would add unnecessary grams.

The Filante SLR is made from the same materials as Wilier's existing superlight Zero SLR: HUS-Mod carbon fibre and liquid crystal polymer. What's HUS-Mod carbon fibre? Wilier says it's a blend of high-quality fibres – again, it's tight-lipped about exactly what's in there – and that the liquid crystal polymer helps improve the absorption of vibration.

Whatever the secret sauce, the Filante is an absolute delight out on the road. As well as being light, it feels stiff. Launch your biggest out-of-the-saddle attack and it remains tight and rigid around the bottom bracket while the fork and stocky head tube keep everything firmly under control up front. Fast cornering feels fabulous and the quick handling allows you to chop and change your line with the minimum of effort.

In terms of geometry, you'll be expecting an aggressive setup, and that's exactly what you get. As mentioned, I've been riding the XL Filante and this size comes with a 57cm effective top tube, a 54cm seat tube (centre of BB to top), and a 16.6cm head tube. The stack is 571mm and the reach is 395mm, giving a stack/reach of 1.45. That's not a crazy figure compared with other race bikes of this size, but you can easily get a low and aero ride position.

Adding/removing two-part headset spacers doesn't require recabling and the stem section of the excellent one-piece Filante bar (365g) comes in five different lengths so you can get your position dialled (Wilier's AccuFit table allows you to replicate the position of your current bike easily).

Perhaps less expected is the level of comfort the Filante provides. Okay, I say 'less expected' but if you've already taken a look at the tyres you're not going to be shocked. Wilier specs Vittoria Corsa Speeds in a 28mm width, and fitted to the brand's own SLR42KC wheels (with a 21mm internal width), they actually measure a whopping 29.5mm across.

Wilier says you can go up to a maximum of 30mm tyres but, as you can see from the pictures, an extra 2mm over what's currently on the bike wouldn't take up all the available space by a long way. I can't really go against Wilier's official advice and suggest that you could fit 32s for some sort of weird caper but, you know, between you and me, you could.

The 42mm-deep rims are very much a U-shape, with an external width of 28mm and a blunt spoke bed. They arrived set up tubeless and the only attention they needed during the month-long test period was a top-up of sealant. Again, some wind tunnel data would strengthen their cred, or at least allow you to justify the expense to your better half and mates.

Mavic's Speed Release thru-axles live up to their name by being quick to use, and their integrated torque control system means that you can't over-tighten them – they just click and refuse to screw in any further when you reach the right point.

The Filante SLR is available as a frameset with the integrated handlebar/stem for £4,790. Wilier says that 'this includes the new 14% Rules of Origin duty plus the extra customs clearance costs in place following Brexit'.

Build options

Various Shimano, SRAM and Campagnolo complete builds are available. Not surprisingly, they're all pretty high end. Our review bike is Shimano Dura-Ace Di2 all the way and everything worked perfectly throughout testing.

My only quibble with the build was with the choice of a compact 50/34-tooth chainset matched up to the 11-30t cassette. The 50 x 11 gear is large enough in most situations, but if you've just dropped 10 grand on an Italian superbike it'll break your heart to watch everyone else go sailing off into the sunset on a long, fast descent as your legs blur in a vain attempt to stay in touch.

Handily, the chainring size, crank length and cassette size can all be specified at the time of order through a Wilier retailer, as can the handlebar width and stem length, and colour. I'd be going for a 53/39T or at least a 52/36T.

Oh, and a bonus quibble: a lot of other bikes at this price – and some considerably cheaper – are specced with power meters these days. It's a very different brand, of course, but the £9,999 Giant TCR Advanced SL 0 Disc gets a Quarq DZero power meter, while the £7,250 Specialized Tarmac SL7 Pro has a SRAM Force eTap AXS groupset, including a power meter. You could point to plenty of £10,000 road bikes that don't come with a power meter, of course, but this might be a consideration for you.

Value

Value is always a tricky one, and Wilier is always going to struggle in this area compared with global giants like, um, Giant, Specialized, Trek, and so on. That said, the new Specialized S-Works Tarmac SL7 Dura-Ace Di2 that Stu reviewed – and loved – last year was £10,500. That bike is chock-full of Specialized's latest tech, and it does include a dual-sided power meter, but the price has now increased to £11,500 – £820 more than the Filante SLR.

The £9,999 Giant TCR Advanced SL 0 Disc I mentioned a minute ago was £9,499 when I reviewed it in July. The Giant is still less expensive than many similarly specced rivals.

> Ultimate superbikes: 14 of the world's most expensive road bikes

If you want to stick to comparisons with other Italian brands, the Bianchi Specialissima Dura-Ace Di2, a lightweight bike rather than an aero bike, with Vision SC40 Disc brake wheels, is £10,500 – so pretty similar to the Wilier Filante.

Summing up

We'd be happier if Wilier backed up its aero claims with some statistical evidence, but there's no denying that the Filante SLR is an incredibly sharp bike, combining enviable frame stiffness with its light weight. It also offers an exceptional ride quality. If you're lucky enough to be in the market for a race-focused superbike, the Filante is right up there mixing it with the best from big-name brands, and it should be on your shortlist. It would certainly be on mine.

Verdict

Lightweight aero superbike that offers quick handling and an excellent ride quality