Video: 6 of the best 2021 aero road bikes – flash bikes built for soaring speeds from Specialized, Wilier, Merida & more

If you like going as fast as possible, then an aero road bike is going to be the thing for you. Here are six of the best that we have ridden and reviewed*. 

> Lightweight vs aero: which is best?

Before we get to the bikes, we should just point out that we will only include products that we have actually reviewed in our six of the best series. Why? Well, we think that it’s the best way to tell you what the best products are. It’s difficult to form a valid opinion of a bike off the back just based on what the bike brands tell us. The bikes that we feature have been ridden and reviewed by our independent team, so you know it’s advice that you can trust.

Specialized S-Works Tarmac SL7 Dura-Ace Di2 - £11,500

Kicking us off is the 2021 Specialized S-Works Tarmac SL7 Dura-Ace Di2. This bike really represents the new age of road race bikes where integration is the name of the game.

> Read our review here

When the new Tarmac was launched, Specialized dedicated Venge aero road bike was actually discontinued, which has given us a slightly different looking Specialized line-up in 2021. The Specialized Aethos has come into the range as the lightweight option, and the Tarmac is left as the one dedicated aero road racer in the Specialized range.

This one is the latest top-end offering 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.

Wilier Filante SLR 2021 - £10,680 

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.

> Read our review here

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. The Filante also  holds onto that speed very well.

Wilier uses truncated NACA aerofoils for the Filante’ tube profiles, which is nothing unusual nowadays. 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. The difference, according to Wilier, is what it has done with the cutoff at the rear of the tube.

> Cycling speed tips: how to get faster on your bike

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 does this mean in the real world? Well, Wilier says that it makes the bike a bit more slippery in a wider range of wind directions.

This is a pretty comfortable bike too, considering it’s a road racer. Wilier specs Vittoria Corsa Speed TLR tyres in a 28mm width, fitted to the brand's own wheels which feature a 21mm internal width. This allows the tyres to balloon out to a whopping 29.5mm.

Merida Reacto Team-E - £9,000

This one is a bike that I had the pleasure of reviewing, and I have to say that I loved my time on the Reacto.

> Read our review here

The bike is a race thoroughbred that excels on flat and rolling terrain. The straight-line speed, stiffness and handling are all brilliant, but the ride may be too firm for some.

Merida says that weight was one of the primary concerns when moving the Reacto to more of an all-around race bike and away from a dedicated aero rig. At 7.5kg on our scales for this size small, there is still some room before you worry the UCI's 6.8kg minimum weight rule, but I'd say it feels plenty lightweight enough.

The low weight certainly helps get you up to speed, but the Reacto really reaches its happy place cruising the flatlands around 40kph and above. The new aero claims aren't massively impressive, but the Reacto was a fast bike already, so saving a whopping two watts because the cables are now hidden is just a little bonus.

Trek Emonda  SL6 Pro - £3,700

In terms of aero, this one is all about heading uphill quickly.

> Read our review here

The latest iteration of the Trek Émonda focuses on aerodynamics more than ever before, which makes this SL6 Pro one very quick and efficient road bike. The stiff frameset offers a firm yet fun ride, while the component choice keeps the weight down to exploit that stiffness on the climbs. It's a very good all-around package.

When he reviewed it, Stu picked up on the fact that the SL6 Pro has quite a firm ride – a little bit old school, he said. By that he meant that a lot of carbon fibre frames have become much more comfortable over the years as designers and manufacturers have learnt about carbon fibre grades, tube profiles and, more importantly, the layup of the composite material.

This isn't a criticism of the Trek at all, it just wasn't quite what Stu was expecting. He actually likes it, saying that he’s a big believer in ultimate performance over comfort when it comes to race bikes, and that is exactly what the Émonda delivers.

The aero tweaks have turned it into a very fast and efficient bike that still manages to deliver on the weight front, and this SL 6 Pro model is so well specced there's no need to update anything when it comes to the components; just the tyres when they wear out.

Scott Addict RC 30 - £3,749

While the Foil is the out-and-out faster bike in Scott’s range, the Addict is one of the best examples of a bike that combines some aero features with exceptional handling and all-day comfort.

> Read our review here

For the latest Addict, Scott has focused heavily on aerodynamics to boost its already impressive performance. By keeping all hoses and cables virtually hidden it is certainly one smooth-looking machine, backed up by plenty of stiffness and a very comfortable rear end.

At the front of this bike, Scott’s components brand Syncros provides the bar and stem, hiding away the cables. Our bike came with mechanical Ultegra shifting, and you really could tell that thought had been put into the cable routing. Shifting wasn’t compromised, and there were no strangle rattles from loose cable.

The ride is very direct. The frame is stiff and like the Reacto, it might be a bit much for some; but that stiffness translates into amazingly quick accelerations if you’re a fan of attacking the group ride. You are? Well them, this is going to be a great bike for you! 

The bike that we tested featured pretty bog-standard aluminium wheels, so it gets even better when you lob some deeper and lighter carbon wheels on.

Cervelo S5 Ultegra Di2 - £8,779.00

The third iteration of Cervelo's S5, its flagship aero road racing bike, was eventually launched in late September 2018 after a four year wait.

> Read our review here

The S5 is very much built with aerodynamics in mind first, with Cervelo then working out how to build vertical compliance and comfort in afterwards. On its bikes built more for day-long riding, such as the R5, Cervelo starts with tube shapes that prioritise vertical compliance and lightness with a shorter, more upright geometry, and forgo the use of ultra-high modulus carbon to create a more damped ride feel.

The bar/stem combo also allows for electronic and mechanical gears to be routed straight through, which means the cables are completely concealed on any spec of S5 you choose.

At the rear end, you’ll need to get the seat post cut down if you’ve got shorter legs like our Jack, but he was instantly a massive fan of the way the S5 kicks forward.

Well, that’s our list of six of the best aero road bikes. Have we missed yours off the list? Tell us in the comments below why it needs to be considered! 

*Prices that appear in the video were correct when the bikes were reviewed. 2021 RRPs appear in this article and in the video description.