All the major bike brands have an aero bike these days, and we've done our own independent testing to find out which is really fastest
Weight may have been the primary concern of bike manufacturers for much of the history of cycling, but the aero bike has become the new big thing in the last few years.
Nearly every company going has an aero bike somewhere in its range. And for good reason. Our independent testing shows that the difference between a good aero bike, and a climbing bike, could be as much as 25 watts at 45kph. It’d take a lot of training to gain 25 watts.
However, as a shopper, of course you want to know which aero road bikes are the good ones. And which are not quite up to the job. Which is where our independent testing really comes in handy.
Cycling Weekly’s independent aero bike testing:
- Trek Madone, Specialized Venge, Canyon Aeroad, Cervelo S5, Giant Propel
- Scott Foil, Bianchi Oltre, Merida Scultrua, Venge Vias (as control)
We’ve listed some of the best aero bikes below – then gone into more detail about what to look for.
It’s worth remembering that though we’ve picked out the top end iterations in most cases, the majority of these bikes are available at a more affordable price point with the same wind cheating frame, and slightly lower end spec. After all – you can always upgrade as you go.
The top three fastest aero bikes tested
Our aero testing (here and here) showed the Trek Madone, Specialized Venge Vias and Scott Foil as being all very close when it comes to the ‘most slippery’ stakes – separated by about 1watt. Which is very much in the realm of experimental error.
Trek Madone Race Shop Ltd
The frame is light and strong, thanks to 700 Series OCLV carbon. There’s a high level of integration, cables are hidden, and Trek have employed their IsoSpeed Decoupler to create a smoother ride.
The only negatives we could find when we reviewed this bike were the cost, and the fact that Zac Efron (apparently) owns one. If you’ve got the cash burning a hole in your pocket, we expect you can overlook the second shortcoming.
- Read the full review here
Specialized S-Works Venge ViAS Di2 aero bike
An exceptionally good looking bike, the Vias frame is available at a range of different spec levels – and it comes with disc brakes too.
A wind cheating frame, which handles better than most aero bikes we’ve tested, the only shortcoming we found was that maintenance isn’t especially easy, and a little more compliance wouldn’t go amiss.
Scott Foil RC
When the Scott Foil proved to be about 1 watt slower than the Venge Vias, we were quite surprised. The Foil features a little less integration – and that’s a plus as it could make it a bit easier to live with.
Scott uses its own truncated aerofoil sections on the downtube, as well as carefully formed shapes at the seat tube and seatpost, the head tube and the fork. An integrated seatpost, skinny top tube and integrated cables all help too.
The Cerveo S5, Canyon Aeroad and Bianchi Oltre XR4 returned similar results in testing – that’s 4-7 watts slower than bikes like the Specialized Venge Vias, Trek Madone and Scott Foil. However – they’ve still got a lot going for them – comfort, aesthetics and value (in that order).
Bianchi Oltre XR4
Aero bikes have a reputation for being a little unforgiving to ride – but the Bianchi XR4 features the brand’s ‘Countervail technology’. Bianchi has embedded a layer of countervail viscoelastic material across the frame, and they claim this increases vibration cancellation by a pretty staggering 80 per cent.
The 2017 edition features a Vision Metron 5D handlebar with integrated stem, which offers a super stiff and responsive front end.
Cervélo S5 aero bike
Cervélo was the first brand to pioneer the aero road bike, with the Soloist in 2002 – so it’s no coincidence that they’re still considered one of the best manufacturers making resistance fighting machines.
The S5 has seen some updates for 2017 that make it a little quicker than previous models, so it’s a super fast frame. However, Cervelo have chosen to leave the cables a little more exposed than other options on the market. Though this adds a tiny fraction to the overall drag, it makes maintenance much quicker.
Cervélo has also taken an interesting approach at the front end – using a flat, aero handlebar that attaches to a standard stem, making fit adjustments much easier for the rider.
- Read the full review here
Canyon Aeroad CF SLX 9.0 Ltd aero bike
Canyon bikes are well known for the excellent value for money they offer. The brand operates a direct sales method, which allows them to save on the cost of overheads, passing some of that saving on to the customer.
Though the Aeroad didn’t prove to be the fastest aero bike on test, it still boasts a significant chunk of free speed on a standard set up, and comes with excellent spec for the price. Not only that, we were impressed with the ride quality, which was more comfortable when compared with others available.
- Read the full review here
As yet untested
We’ve not had a chance to aero test these two, but we reckon they’ll prove fast…
3T Strada aero road bike
Possibly the most futuristic road bike on the market, the 3T Strada has received a lot of attention, with a huge focus on its 1x system (on our build, 50T at the front, 11-36 on the rear).
3T says that the 1x approach helps to clear up the “worst area aerodynamically” – but of course it means that jumps between the gears are large and there’s potentially to be over or under geared.
We’ve tested the bike on the road, and found it a little bit twitchy. We’ve not yet assessed its aero claims – so watch this space.
- Read the full review of the 3T Strada aero road bike here
Giant Propel Advanced SL 0 aero bike
A model that’s been on the market for a little while, the Giant Propel Advanced isn’t the fastest of the fast aero bikes on the market – but it is light, stiff and provides nimble handling, though it is a little harsh to ride.
Giant have opted to use their own stem – which is of a wider diameter than most, and the seat post is integrated and needs to be cut to the right length – so you need to be pretty sure of your ideal set up before you invest.
- Read the full review here
Planet X EC-130E aero bike
If you want aero, with a slightly more affordable price tag, this one could be for you.
Of the aero bikes on the market, the Planet X EC 130 isn’t the most advanced – it probably wouldn’t win in a wind tunnel with its standard brake positioning and fairly faff free cable routing. However – what we like the most about this model is the compromise between speed and practicality.
Whilst the Planet X EC-130E aero bike won’t leave you scratching your head every time you need to make an adjustment, it features a super stiff bottom bracket and a sharp front end that’ll cut through the air like a knife through the butter you left on the windowsill all day.
- Read the full review of the Planet X EC-130E
- Buy now at Planet X for £2,099.99 (other build options available)
Cycling Weekly’s own aero bike testing experiments
Well that’s a very good question that, with Cycling Weekly wind tunnel still seeking funding from the powers that be, we can’t answer with complete scientific accuracy. However, we have conducted a couple of experiments that have compared the performances of aero bikes with non-aero bikes.
In the first of these, we put the two bikes to the test in what should be the aero bike’s home turf: the velodrome. We rode each bike (a Cervelo S5 and Canyon Ultimate CF SLX) for 10 minutes at 200W and 10 minutes at 300W, with the aero bike being 275m ahead and 1.7kph faster when ridden at 200W, and 435m ahead and 2.6kph faster when ridden at 300W.
In the second experiment we pitched an aero bike (again the Cervelo S5) against a lightweight bike (a Focus Izalco Max) on a climb, tackling Box Hill in Surrey twice on each bike, again at 200W and 300W, to see if the aero bike would still be faster even in the hills despite the Cervelo S5 being 800g heavier.
However, this time it was the lightweight bike that came out on top. At 200W, it took our test rider 9:24 to tackle the 2.5km climb on the aero bike at an average speed of 15kph, while the lightweight bike was 18 seconds faster with an average speed of 16kph.
At 300W, the lightweight bike was still faster, but the gap between the two was reduced, with the aero bike only being seven seconds slower with a 0.4kph difference in speed. This shows how much more important aerodynamics become at higher speeds, while weight is more of a factor at lower speeds.
The take home message then, is for most riders over most terrains, an aero bike will be faster than a lightweight bike. The only case where weight begins to become more of a factor is on steeper climbs where you’re travelling more slowly, and even then any time gains could well be balanced out on the descent?
What features should I look out for in an aero bike?
At a most basic level, all aero bikes should come with tubes that have been shaped to smooth airflow, meaning that they will have a slender front profile but being extended rearwards. However, manufacturers can’t go crazy if they want to see their bikes used in races, with the UCI’s 3:1 rule restricting the ways in which they can shape the tubes.
This rule means that the depth of a tube’s profile (or indeed any other part of a bicycle) cannont be more than three times its width. So if a bike’s down tube is two centimetres wide when viewed from the front, then it cannot be more than six centimetres wide when viewed from the side.
Watch: Cycling Weekly Aero Bike of the Year 2016
In an attempt to continue to improve the aerodynamics of their bikes while staying within this rule, many manufacturers now use kamm-tail tube profiles. This means that the tube retains a traditional aerofoil shape at the front, but with the back half lopped off to give it a flat back.
Integration is the latest big trend when it comes to aero bikes, with the latest aero bikes such as the Specialized S-Works Venge ViAS and the Trek Madone aiming to hide as much hardware as possible within the frame.
Key to this is cable routing. The sleekest aero bikes keep the gear and brake cables hidden for as long as possible, routing them through the handlebars, stem, and frame before they emerge close to their partner components, usually on the backside of the tubes to keep them out of the wind. At the next level down from this the cables are not routed through the handlebars and stem, but do at least enter the down tube behind the head tube to keep the cable entry out of the wind.
Integrated brakes are also found on many aero bikes. At the front, some manufacturers such as Look and Boardman position the brake within the fork, while the Specialized S-Works Venge ViAS puts them on the rear side of the fork. However, most aero bikes still come with the front brake mounted in the standard position on the front of the fork, although often with direct-mount brakes to bring the caliper closer to the frame.
When the first aero bikes emerged a few years ago, most manufacturers decided that the most aero place to stick the rear brake was by the bottom bracket, however the aerodynamic benefit of this this is questionable with that area having some pretty irredemably “dirty” air caused by the movement of the cranks and chainrings.
Increasingly we are seeing company’s go back to positioning the rear brake on the seatstays, but again using direct-mount brakes to bring them closer the the frame to smooth airflow, although Specialized has again chosen to do things a bit differently, giving the Venge ViAS a rear brake placed on the trailing edge of the seat tube.
However, possibly the most important part (or parts) of a seriously sleek aero bike are the wheels. According to Kevin Quan of Knight composites, a 95mm deep rim (which is admittedly incredibly deep) will save a typical rider 35 watts compared to a standard box section wheel at time trial speeds. That said, it is also important to consider the weight of deep section wheels and their effect on handling, particularly if you live in a hilly or windy part of the world.
Other than this, many aero bikes will also come with other aerodynamically engineered components, such as aerofoil-shaped handlebars or seatposts, and even, in the case of the Look 795, and aero crankset.
How easy are aero bikes to live with?
Yes, for most people on most terrains, an aero bike will be faster, but if you’re considering buying one, you also have to weigh up what day-to-day life will be like with your new pride and joy.
Unfortunately, the more aerodynamic the bike, the more difficult it can be to live with. No more so is this the case than with integrated cabling. Yes, this helps you cut through the wind just that little bit easier, but for the home mechanic (and even for a few WorldTour professional mechanics that we’ve spoken too) they can be a nightmare. The cable routing is often complicated and if you do have a problem with your shifting or braking, then the cause could well be hidden somewhere within the frame.
The integrated brakes on aero bikes can also be a bit of a faff. The traditional positioning of brakes on the seatstays and the front of the fork makes maintenance and adjustment a doddle, but once you move the brakes to within the fork and beneath the bottom bracket, then the extra time you take doing simple tasks like changing brake pads will be much more than the few seconds you can save in the local time trial.
Finally, if you’re going to get the most out of your aero bike, then you might occasionally find yourself riding in the dark. In this case, aerodynamic seatposts and handlebars can make it a little tricky to fit lights, while the seatpost design may also limit the saddle bags you can use.
How else can I be more aero?
Before you rush, wallet open, to your local bike shop in search of the latest aero bike, it’s worth considering that there are plenty of other much cheaper ways to make some aerodynamic gains.
The vast majority of the wind resistance that you have to overcome while cycling is caused by, well, you, so your position and clothing choice can make a big difference to your speed. Riding in a low, crouched position with your hands on the the hoods is roughly 20 per cent more aerodynamic than riding upright with your hands on the tops.
Similarly, tight-fitting aerodynamic clothing and an aero helmet can also make a significant difference. The benefits might not be as stark as with changing your position, but if you’re riding along with a bag raincap unzipped and flapping in the wind, then you can wave goodbye to any gains that you might have got from your expensive aero bike and flash deep sections wheels.
How much should I pay for an aero bike?
With aero bikes now being available at almost all price points, it’s more a case of how much can you afford to pay rather than how much do you need to pay.
At the top-end of the scale, it’s not unusual to see aero bikes pushing hard against the £10,000 barrier, which should be enough to get you a cutting-edge frame matched with some pretty tasy components and deep section wheels for a seriously aero machine.
However, for a fraction of this price, you will often be able to pick up a bike with a frame that might not have the same high-quality carbon-fibre (so will be usually be less stiff and heavier), but will at least have the same shape tubes which will still be subject to the same laws of physics.
Wheel choice is also important when considering how much to pay for an aero bike. If you already have aerodynamic, deep section wheels, then there’s no point in paying more money for a an aero bike that comes with similarly posh wheels. Instead, buy the bike with the cheaper wheels, take these off to use as training wheels, then put on the deep section wheels that you already own for race days.