Specialized S-Works Tarmac SL7 Dura-Ace Di2 2021

The S-Works Tarmac SL7 Dura-Ace Di2 is one of the latest top-end offerings from Specialized that now focuses just as much on aerodynamics as it does on weight – or lack of it. The frameset has seen various tweaks over its predecessor, and when paired with aero components like the handlebar and wheels makes the SL7 a very, very fast bike indeed. This model comes at an eye-watering price, though.

Ride

When I wrote my First ride review piece I stated that this Tarmac SL7 was the fastest bike I had ever ridden, and I still stand by that. As a complete package this S-Works is phenomenally efficient and therefore fast.

> Find your nearest dealer here

Coming in a smidge over the UCI's minimum weight limit of 6.8kg (15lb), this 56cm S-Works is obviously no slouch off the line, so acceleration is very brisk and keeping up with the ebb and flow of the traffic in urban areas or on busy roads is easy.

Once up to speed, aerodynamics comes into play, but they seem to be far more important at much lower velocities than most aero bikes I've ridden. Some, such as the Storck Aerfast and Orro Venturi, feel as though they require less effort to keep moving as they get to around the 23mph mark; a lot of deep wheels create this effect too, highlighting the sort of speeds at which aerodynamics really start to make a difference. On the S-Works, though, that feeling kicks in at around 18mph. Once you get the bike up there it just rolls along, like you are always on top of the gear, and it makes for a very efficient ride and an impressive average speed.

It even helps when you come to a climb as you can hit the base of it using a lot less effort than you normally would, so you can carry the speed into the incline. Then, as the aero benefits start to diminish, that low weight helps you power to the top of the hill.

A lot of the aerodynamic bonuses are coming from the Roval Rapide CLX wheels, the front especially with its 51mm depth and massive 35mm external rim width. It's a similar sort of design found on the Hunt 48 Limitless Aero Disc wheels that I've been riding recently, a wheelset that is also unbelievably fast.

Alongside the low weight and wind-cheating design, the Tarmac SL7 also delivers on the stiffness front. Compared with a lot of the tightest frames out there, Specialized hasn't exactly gone for massive tube profiles to create the stiffness and nor has it gone for a wider bottom bracket shell that would use press-fit bearing cups located inside the frame. It has instead plumped for a threaded option, with the cups mounted externally.

Even with all of this stiffness, the SL7 hasn't sacrificed the comfort levels. It's a peloton-ready race machine, so don't go expecting a cosseting ride, but it's firm without any irritating levels of harshness.

I had the 26mm tyres pumped up hard and had no overall issues at all with discomfort in my hands or feet when riding for four to five hours at a time, but if you want to bring in a little bit more 'suspension' then you can exploit the Tarmac's 32mm max tyre width.

As you'd expect, the geometry is pretty aggressive – there is no relaxed endurance front end to be found here or an upright riding position.

This 56cm size has 73.5-degree head and seat angles and stack and reach measurements of 555mm and 398mm respectively, which gives quite a long and low setup on the bike. If it was my Tarmac, I would take out the 20mm of spacers sitting below the stem to really get the most out of the low position.

The steering is quick, which makes the S-Works an absolute blast when descending. Very light, stiff bikes can sometimes feel a little flighty over rough road surfaces at very high speed, but the Tarmac never really does. The whole bike feels very balanced and thanks to the handling being very precise, you can carry a lot of speed into the corners.

You get plenty of feedback from the supple Specialized Cotton tyres, too, which really helps the confidence levels.

Overall, this bike really does deliver on all the attributes you'd want of a top-flight race machine: speed, stiffness, handling and comfort.

Frame, fork and aero components

The SL7 was officially launched on the 28th of July, and Mat wrote a full in-depth piece on everything that you need to know about the new Tarmac which is definitely worth a read if you are interested in the design and manufacturing that went into its inception.

I'll give you a brief run-through here though.

Specialized has its own wind tunnel – or the Win Tunnel as it calls it – and it's obviously a big advantage having the ability to trial designs in-house.

For aerodynamics it'll come as no surprise that the company has focused on tube shapes. Traditional aero bikes use quite large tube profiles to achieve the wind-cheating benefits. Larger tubes mean more material, though, and that brings weight increases.

The head tube and seat tube, seatstays and fork blades all use designs from Specialized's FreeFoil Shape Library, a collection of aerofoil shapes that it has developed.

The head tube, for example, has an hourglass shape, only being wider at the top and bottom to accept the bearing cups.

The seatstays are dropped too, something Specialized has done for aerodynamic reasons right throughout its range all the way down to the aluminium Allez models.

The real key, though, is clean lines: everything that can be hidden is hidden.

From the front we'll start with the Aerofly II handlebar, which has been taken from the Venge. The bar has a very slim profile – it's almost three times wider at the tops than the front edge that is striking the air; not only is it aero, it's also stiff and, from my point of view, impressively comfortable.

Even better, Specialized has kept it as a standalone handlebar rather than an all-in-one system with an integrated stem. This means you still get the option of some adjustment.

The hoses and cables (or in this case wires) are internally routed through the bar and are held in position by a neat clamp arrangement in front of the stem before being fed down into the head tube via the spacers. This is one of the biggest changes I've seen to 2021 bikes, with many of those I'm currently testing following their own take on this design; it certainly gives a very clean looking front end.

Here you are only seeing the hoses/cables/wires again right before they are connected to the components.

The stem also has a clean look with a top cover that hides all of the bolts and headset gubbins. There are three options that come with the bike that will work with various builds, mechanical or electronic, and one that will work with a standard stem plus round spacers should you not want to trim the steerer straight away.

The seatpost hasn't been neglected either. It has a teardrop shape to it with a flattened rear to match the seat tube and there is no clamp as such: the Tarmac uses an expanding wedge design sat under the rubber cover on the top tube.

The seatpost also houses the Di2 junction box at the rear.

When it comes to material, the S-Works models use the top end FACT 12r carbon fibre grade, while others lower in the range use FACT 10r. The main difference between the two is weight, as both use the same tubing profiles and have corresponding stiffness levels.

FACT 12r uses less material to achieve this stiffness, so it's a lighter build by around 15% – around 800g, give or take.

Specialized offers the Tarmac in a decent range of sizes from 44cm through to 61cm, which equates to top tube lengths of 496mm to 595mm. The S-Works also comes in two colours, red/black with white decals, or this rather subdued natural carbon finish which has a bit of a silver/green finish to it when it catches the sunlight.

Everything else spec-wise about the frame is exactly as you'd expect really: flat mounts for the disc callipers and 12mm thru-axles front and rear.

Groupset

Other than the special edition Sagan bike, this is pretty much the flagship of the Tarmac SL7 range, so it's no surprise to see a full Shimano Dura-Ace Di2 groupset, with a power meter included.

Not only is it a beautiful looking gear system, you also can't fault the performance. The changes are fast and crisp, and the large buttons on the lever make sure you don't fudge a critical shift in the heat of the moment.

Can you tell the difference between this and Ultegra Di2? Barely – unless you are riding the two side by side, which I am lucky enough to have done, and then you find that Dura-Ace is just a little bit quicker and shifts a smidgen better under load.

Gear-wise Spesh has gone for a 52/36-tooth chainset paired to an 11-30T cassette, which gives a good balance of gears right across the range. While it is a pro-level bike that's probably more used to seeing a 53/39T chainset and a closer ratio cassette, for us mere mortals this setup works well.

I have to say, if it was my money I'd go for the eTap model for the same money. I love the ratios found on SRAM's latest 12-speed groupsets, which I talked about in my Vitus Vitesse Evo Team and Canyon Endurace CF SLX Disc 8.0 reviews.

On the odd occasion that you need to slow the SL7 down, you'll find that the hydraulic setup is absolutely brilliant. Its 160mm front disc and 140mm rear offer plenty of stopping power.

The rotors can be a little flexible, mind, so you really need to crank up the tightness on the thru-axle otherwise, like me, you'll get some rotor rub in the corners and also when they heat up. It was most noticeable for me when I was stuck behind a tractor and trailer on a downhill and needed to drag the front brake a bit.

That aside, it's the usual thing from Shimano's braking components: loads of power but with loads of modulation whether wet or dry. The way I ride makes me a very heavy late braker and I've never locked up a front wheel in my life, even in the wet. The feel and feedback from the levers here mean that'll remain the case even with the amount of power you have at your fingertips.

Wheels and tyres

I touched on the wheels earlier. The Roval Rapide CLXs are deep and wide: 51mm deep and 35mm wide at the front, 60mm and 30mm at the rear.

The front is taking the brunt of the airflow which is why its shape is more pronounced than the rear. Both have an internal width of 21mm, which means they are still compatible with 25mm tyres, one of the most common sizes still used on race bikes.

The thinking is that the widest part of the tyre/rim combination needs to be about a third of the way back from the leading edge so therefore the rim needs to be wider than the tyre. It does look a little disconcerting from a rider's point of view when you look down and see all of this carbon fibre poking out either side of the tyre, but after testing the Hunts that I mentioned earlier, it really does make a difference to the aerodynamics.

One thing that some might find odd is that there is no tubeless compatibility. Specialized says that when the designers looked at what they wanted to achieve in terms of aerodynamics, weight, stability and ride quality, going tubeless wasn't possible.

Hunt managed it with the 48 Limitless, though, and while they are probably around 150g to 200g heavier, in the real world when I swapped them over there was no discernible difference.

Personally, on the road I can take or leave tubeless. On the gravel, yes, but on the road I'm not bothered about dropping tyre pressures for comfort. I like them high, and over the last 20 years punctures have been few and far between.

> What they don't tell you about tubeless

The Specialized Cotton tyres fitted here to the S-works have a 320TPI (thread per inch) carcass and they feel super-supple, even at high pressures – something you don't always get from a tubeless tyre.

The compound used is impressively grippy too, and I really loved chucking this bike into the bends hard.

The super-smooth rubber used for the central tread rolls very well and wear rates aren't looking too bad either. It is cool to see some little dimples in the tread too, which will let you know that they are wearing out.

And finally... the saddle

It's a Body Geometry S-Works Power with a carbon fibre base and rails. I especially like the stubby design – it suits the kind of hard, powerful riding I found the S-Works kept egging me on to do, and its firm padding is very supportive while being comfortable.

Value

At ten-and-a-half-grand, value is a strange concept but let's just say that money is no object. How does it compare to other peloton-ready machines?

Trek has recently gone down a similar route with its Emonda, giving it an aero edge while retaining the lightweight frameset. The similarly specced SLR 9 model comes in a few grams lighter (claimed), but costs £9,700.

> Buyer’s Guide: 21 of the best and fastest 2020 aero road bikes

Liam is currently riding Merida's take on the aero theme, the Reacto Team Disc. It weighs in at 7.5kg on the road.cc Scales of Truth, but even with the Dura-Ace Di2 group and power meter it 'only' comes in at £9,000.

Overall

As a technical exercise this is one hell of a bike. It really does deliver the whole package. It's great to ride, super-fast with sweet handling, and thanks to that low weight and the excellent wheels all it makes you want to do is smash it everywhere.

True, it's a lot of money, but wow!

Verdict

Eye-watering price but an exceptional performance