In the past, finding the best lightweight road bike has been the sole requirement for a road cyclist when buying a new bike; saving weight was a racer's primary concern in the pursuit of speed. Such was the obsession that in cult book The Rider, Tim Krabbé recounts being told by another cyclist that, "Anquetil always moved his water bottle to his back pocket during climbs, so his bike would be lighter."
Conversely, the contemporary fashion for aero bikes might, at first glance, make lightweight bikes seem like a bit of an anachronism, but there are actually still a number of sound reasons why you should consider one as your next bike.
Read on for Cyclingnews' pick of the best lightweight bikes available today.
Cannondale SuperSix Evo Hi-Mod Dura-Ace Di2 Disc
Progressive aero update to one of the most acclaimed lightweight bikes
Price: £8,999 | Weight: 7.49kg | Brake: Disc | Frame: Carbon | Sizes: XS-XXL
With its renowned blend of low weight and enormous stiffness, the Cannondale SuperSix has long been considered one of the best bikes for climbing, but its round-tubed design was admittedly getting a little long in the tooth.
The SuperSix 2020 brings a complete design overhaul, with truncated aerofoil tubing, a sleek integrated cockpit and system designed wheels. The SuperSix maintains the glorious pedalling efficiency, low weight and razor-sharp handling, but dropped seat stays increase comfort and hydraulic disc brakes bring improved braking control and tyre clearance.
Now arguably more of an all-rounder than just a pure climbing bike, the Cannondale SuperSix does sit a few hundred grams over the UCI weight limit, but the aerodynamic gains will likely offset this on less steep climbs.
The only let-down is the activation fee for the Power2Max integrated power meter. It's brilliant that the bike comes with one of the market's best power meters already installed, but considering how much this bike costs, it's a little annoying that you have to pay an extra $490/€490 to access its full potential.
Giant TCR Advanced SL 1
An evolution of the original compact road frame design – if it ain't broke, don't fix it
Price: £5,999 | Weight: 7.32kg | Brake: Disc | Frame: Carbon | Sizes: S-L
It was legendary bicycle engineer Mike Burrows (designer of the Lotus 108 and 110 bikes) who created the Giant TCR's compact frame design in the mid-90s. Back then, among a sea of bikes with horizontal top tubes, it represented a radical departure from the norm, but it proved to be a winning design and spawned countless copies.
We understand a new 2021 TCR is on the way, but having had a closer look, it looks to be evolution than revolution, and when the 2020 model is so darn refined, why wait?
The 2020 TCR encompasses over 20 years of refinements on the original design, but the fundamentals remain the same; the compact frame triangles make for an impressively stiff and lightweight frameset. Tubes are shaped to maximise stiffness to weight, rather than aerodynamics, meaning this is a true climbers bike. The frameset is so lightweight that even a build with Shimano Ultegra R8050 Di2, Giant Power Pro integrated power meter and 42mm SLR-1 Giant carbon wheels can hit the UCI weight limit of 6.8kg.
This model, however, uses the same wheels but is replete with SRAM's user-friendly Force Etap wireless groupset, disc brakes, and Quarq DZero power meter at a still-competitive 7.35kg.
The OverDrive 2 oversized fork and massive Contact SLR carbon stem make for remarkable steering stiffness, which translates into wonderfully precise handling out on the road. Giant retains a separate handlebar and stem setup on the TCR, which trades off the aerodynamic efficiency of an integrated design (such as that found on the Giant Propel), for the adjustability and user-friendliness that a traditional setup offers.
The only minor niggle is that the integrated aero seat post can make the frame a bit of a faff to travel with, and potentially limits the frame's resale value, as you can have to cut it down to match your own specific saddle height, and there's only a limited range of adjustability from there.
Specialized S-Works Tarmac SL6 Disc Dura-Ace Di2
Hugely popular, WorldTour race winning lightweight bike, now more aerodynamic, more comfortable and with disc brakes
Price: £9,500 | Weight: 6.8kg | Brake: Disc | Frame: Carbon | Sizes: 44cm-61cm
The latest version of Specialized hugely popular Tarmac retains the fantastic efficiency and handling we've come to expect, but goes and slows faster than ever before.
Time in the Specialized Win Tunnel has led to dropped seatstays and redesigned tube shapes, that Specialized claims make the new Tarmac as aerodynamic as the original Specialized Venge, even with the addition of hydraulic disc brakes.
It's pricey, but you do arguably get a lot for your money. Specialized specs its own components and wheels, but in every case these arguably rival or surpass offerings from dedicated component brands. You get a set of Specialized's S-Works Power cranks, a carbon railed S-Works Toupé saddle, carbon handlebars and the Roval CLX 50 Disc carbon wheels come tubeless ready, with CeramicSpeed bearings and Specialized Turbo Cotton tyres.
Specialized makes a big deal about the fact that each frame and fork size in the range is built with their Rider-First Engineering design, which means each size gets specific carbon layups and fork tapers, so that ride quality is maintained across the board.
Unlike some other brands, however, Specialized has decided that gender-specific geometries aren't actually necessary, and instead specs different contact point components and crank lengths on its women's specific builds. It's hard for this writer to say whether that's the right approach, but it seems to work just fine for the riders of the Boels Dolmans Cyclingteam.
Scott Addict RC Premium
So refined that Mitchelton-Scott will take to every race this season
Price: £8,999 | Weight: 7.12kg | Brake: Disc | Frame: Carbon | Sizes: 47cm-61cm
Such is the rounded performance of the latest iteration Scott's latest road bike, the entire Mitchelton-Scott team has committed to using the Addict RC Disc for its entire 2020 race calendar.
The Addict RC Premium is one step off the range-topping model in the Scott range - that accolade goes to the RC Ultimate at £10,799 - the Premium is fitted with DT Swiss wheels, a full Shimano Dura-Ace Di2 disc brake groupset, and the fully integrated cockpit that sees cables hidden from sight entirely.
Be sure to get your position right early on, though, as the integrated cockpit doesn't facilitate a simple stem swap, and the addition or removal of a headset spacer will require a complete front-end rebuild.
Bianchi Specialissima CV Ultegra
Bianchi's range-topping lightweight frameset specced to a budget
Price: £4,800 | Weight: 7.55kg | Brake: Rim | Frame: Carbon | Sizes: 47cm-61cm
While more premium models exist in the Bianchi range, we see this Specialissima as a great halfway step into the realms of the top-of-the-range lightweight bikes.
With the premium Specialissima frameset hitting the shelves at £3,899.99, this model completes the build with some aluminium Fulcrum wheels and a full Ultegra groupset for £900 more. At 7.55kg, it's already competitive on the scales, but if you're looking to build your way to owning the best lightweight bike, the Specialissima Ultegra could be the starting point you need.
Alternatively, if you're looking to spend big, the Dura-Ace Di2 disc version can be had with DT Swiss wheels at £10,500.
BMC Teammachine SLR01 Disc Two
Forward thinking bike design that seemed to inspire almost every other brand
Price: £9,499 | Weight: 7.14kg | Brake: Disc | Frame: Carbon | Sizes: XXS-XXL
Dropping the seat stays for improved comfort and aerodynamics was a 2019 bike-design must-have, but the BMC commitment to progressive bicycle design is such that they debuted this feature back in 2010 on the Teammachine.
The combination of massive pedalling stiffness from the oversized down tube and bottom bracket area, combined with the comfort gained from thin, dropped seat stays, made this design a winner from the start. Cadel Evans promptly rode to victory in the Tour de France only a year later, in 2011, and it continues to be the bike of choice for most riders at Dimension Data, thanks to its blend of efficiency, comfort and perfectly balanced handling.
With the addition of hydraulic disc brakes, a semi-integrated cockpit system (that still retains adjustability for both fit and maintenance) and updated cable management, the Teammachine is more evolution than revolution, but this just shows how advanced the original design was at the time. There's little about this bike that looks out of date.
We'd perhaps like to see a nod towards more aerodynamic tube shapes on future models, but the only real downside is that you'll need deep pockets to get hold of one.
Trek Emonda SLR 7 Disc
A superbike designed in conjunction with Alberto Contador, that’s now just as quick going down hills as it is at going up them
Price: £5,300 | Weight: 7.07kg | Brake: Disc | Frame: Carbon | Sizes: 47cm-62cm
Once a pure climbing machine, built to give Alberto Contador an ideal platform on which to unleash his infamous out of the saddle attacks, the addition of hydraulic disc brakes and clearance for up to 30mm tyres widens its potential remit considerably.
With Ultegra Di2 and Bontrager Aeolus Pro 3 wheels, the Trek Emonda SLR 7 Disc might not be the top of the range model, but it nevertheless only gives away 207g to the UCI weight limit. This is thanks largely to its superlight frame which is, rather incredibly, claimed to weigh just 665g.
The 2020 model carries the same form factor as the '18 and '19 models, and while we're expecting an overhaul at some point during 2020, we don't expect Trek will shave any more grams from the frameset, so the current model is as feathery as you're likely to get.
Available in a wide range of sizes and finished with impressive components from Bontrager, all of Trek's bikes can be customised through their Project One programme. The options are extensive – from paint jobs through to practically every major component on the bike (though naturally, any upgrades will increase the overall cost) – so if the stock Purple Phaze paint job isn't to your taste, for example, you should still be able to find something to suit.
Canyon Ultimate CF SLX Disc 9.0
Great value, super-efficient lightweight bike with top-of-the-line spec
Price: £6,499 | Weight: 7.1kg | Brake: Disc | Frame: Carbon | Sizes: XXS-XXL
With Canyon's direct-to-consumer approach, it's hard to argue the value for money aspect of the German behemoth's range. While this particular model is still a considerable investment at £6,499, the 2020 Ultimate CF SLX can be had for as little as £3,899.00.
Women's versions are available, and finishing kit varies between the two genders - such as the VCLS post being included on the equivalent women's bike. Canyon claims the women's frameset is lighter and more aerodynamic than the men's version, but then it contradicts this with claimed weights of 7.07kg (women's) to 6.89kg (men's) for the ETAP disc version.
The Dura-Ace version sees an integrated cockpit, albeit with cables on show, DT Swiss ARC 1400 Dicut wheels paired with Schwalbe Pro One Evo 25mm tyres, and a Fizik Antares R3 saddle.
Cervelo R5 Red eTap AXS
A no-compromise lightweight bike that hides its performance credentials behind classic looks
Price: £8,399 | Weight: 6.9kg | Brake: Disc | Frame: Carbon | Sizes: XS-XXL
The bike of choice for former Giro d'Italia champion Tom Dumoulin, the Cervelo R5 is a bit of a wolf in sheep’s clothing. It would be easy to look at the traditional frame shape and assume it’s a vestige of a by-gone era (especially compared to wild aero design of the Cervelo S5 Disc), but you’d be far from the truth.
The Cervelo R5 is built from Cervelo's Squoval™ Max aerodynamic tubing, tuned to balance phenomenal levels of stiffness with low weight, whilst a stable yet racy geometry and hydraulic disc brakes offer confidence-inspiring handling. It also has clearance for 30mm tyres, so if you want more volume for grip and comfort on rough roads, this bike can handle it.
Up front, Cervelo specs its own carbon stem and handlebars. There are nods to aerodynamics here, but Cervelo hasn't yet gone down the route of full S5-style cockpit integration with the R5.
This invariably means a small aerodynamic penalty, but it does also mean you can easily change the stem length or handlebar width to suit your personal fit requirements – something that might not be possible with a fully integrated system.
Wilier Zero SLR Disc Dura-Ace Di2
Thoroughly modern lightweight bike from one of the oldest racing bike manufacturers in the world
Price: €11,100 | Weight: 6.8kg | Brake: Disc | Frame: Carbon | Sizes: XS-XXL
Despite their illustrious histories, Italian manufacturers are generally not renowned for being on the cutting edge of bicycle design. We tend to think of Italian racing bikes as beautiful, classic, perhaps even old fashioned – but the reality is that, with Wilier at least, this couldn't be further from the truth.
The Zero SLR Disc is the latest lightweight bike from Wilier. Borrowing design cues from their Cento10 Pro aero bike, it's a thoroughly modern lightweight bike. It ticks all the boxes; a super lightweight carbon frame with truncated aerofoil tube shapes, integrated handlebars with fully hidden cables, hydraulic disc brakes, carbon wheels and clearance for 28mm tyres.
Its tried and tested geometry, and stiff frame and fork mean handling is great, and its clean lines and complete cable integration make it a real looker. Wilier is kind enough to offer some very nice paint jobs as well – matte black with white detailing, matte velvet red and a glossy admiral blue. The matte black frameset is slightly lighter, but go for the red or blue for that essential touch of Italian flair.
There's no denying that this is a pretty expensive bike – Wilier retains that classic Italian bike characteristic – but you're buying into a European brand with over 100 years of experience in making bikes, and all of the racing heritage that comes with that.
As of yet, there doesn't appear to be any women's specific versions available, but, hopefully, that’s something Wilier will offer in the near future.
The 6.8kg UCI weight limit
With the UCI weight limit seemingly stuck at 6.8kg, 'lightweight' has been largely defined at that point, and brands have been able to focus their attention on improving other areas of the bike, instead of simply chasing grams in a race to the bottom (although, naturally, that is still a thing).
Where aero bikes often have to make compromises on things like handling, ride quality, fit and user-friendliness in pursuit of all-out speed, lightweight road bikes have tended to become the all-rounders of road cycling, with development focused more on these important, but often undervalued characteristics.
Such are the improvements in these areas that many WorldTour pros still choose to ride lightweight bikes over their sponsors' aero-bike offerings, despite the apparent penalty in aerodynamic efficiency.
When does a lightweight bike make the difference?
The data tells us that aerodynamic bikes are faster on flat and rolling courses, but let's be honest – the hills are still where it really counts. The important Strava segments are, generally, not boring sections of flat or rolling road, they’re hills, and, on the proper hills, lower weight still beats aerodynamics.
One relatively recent development is the appearance of disc brakes on the best lightweight bikes. Rim brakes have long been favoured because of the difference in weight, but the gap has narrowed considerably, and it's worth considering that what goes up must also come down.
You might appreciate the improved power, consistency and modulation of hydraulic disc brakes when you're coming back down that 20 per cent hill, with your heart rate pushing off the scale after a full-gas KOM attempt, and it's largely accepted that disc brakes offer better braking performance, especially when the conditions take a turn for the worse.
Perhaps more crucially, lightweight bikes still retain the power to impress your friends or family members, because weight is tangible. Show them an incredibly expensive aero bike and the first thing they'll do is pick it up and complain that, "It's quite heavy… How much did you say this cost?"
By the time you've started explaining that "over a typical 40km rolling course, performance modelling shows that this bike is 45 seconds faster at 50kph than an equivalent lightweight bike…" they'll likely have lost interest and wandered off, thinking that you got royally ripped off.
A lightweight bike provides an obvious tangible difference, and, sometimes, that provides a greater psychological benefit than the few intangible seconds offered by manufacturers.
Unsurprisingly, carbon fibre dominates the scene for lightweight road bikes. Its unique, tunable characteristics make it the perfect material for making light and stiff bikes that excel when pointed uphill. The downside is that these lightweight frames and components tend to come at an exorbitant cost.
As the great Keith Bontrager once said: "Strong, light, cheap. Pick two." That said, If the UCI limit is what you're looking at, you don't necessarily need to buy the top-of-the-range model these days, which will often actually be lighter than the UCI's minimum weight limit. Some brands are even able to offer builds with Shimano Ultegra that can still hit the 6.8kg benchmark; just don't expect them to be particularly cheap.
Of course, bikes are readily discounted, so it's worth taking a look at our roundup of the best road bike deals to find the best bike-to-price ratio.
What do you think is the best UCI legal lightweight bike currently on the market? Are lightweight bikes even still relevant in the era of 'aero is everything'? Let us know what you think in the comments below.