The road cycling world is obsessed with aerodynamics these days but many people still love the feel and handling of lightweight bikes, and that’s exactly what we’ve got here.
Over the vast majority of routes, an aero bike will beat a lightweight one – that has been proved countless times – but there’s something about a light bike that few of us can resist… and if you can have lightweight and aero in the same package, so much the better.
As a rule, rim brakes are lighter than disc brakes, but we've included a lot of disc brake bikes here because that's the way the market is heading.
Specialized released its new Aethos last autumn, calling it “the lightest disc brake road bike ever made” with everyday – albeit high-end – components.
Although Specialized says the design is focused on ride quality rather than a low weight in itself, the S-Works frame weighs just 588g (56cm version) with complete bikes start at just 5.9kg – way below the UCI’s 6.8kg minimum weight limit for racing.
“We used [supercomputer simulations] to subtly alter round tube shapes,” says Specialized. “This made them more conical in key areas to deliver huge gains in stiffness and balance with the minimum amount of material.”
The designers say that they eliminated ‘lazy fibres’ – meaning that every fibre should be loaded and tense – doing a job. They also used larger, longer, and more continuous plies in the layup to achieve consistent positioning of material, so they were able to reduce the number of plies by 11% compared to the Tarmac S-Works SL6.
The frame was carbon fibre and weighed as little as 600g – that’s for the Di2 version of the small-sized model. The proprietary THM Scapula CT-X fork added just 265g. The bike used coated CeramicSpeed bearings.
The Vial Evo Ultra was fitted with AX Lightness’ own U 24T wheels. Like the frame, these were handmade in Germany.
Many of the other components were AX Lightness’ own too, including the Europa seatpost, the minimalist Leaf Plus saddle, along with the carbon stem, brakes and bottle cage.
THM provided the cranks while the chainrings were Praxis Works.
That show bike was an exercise in just how light you can make a road bike by throwing money at it.
These days an AX Lightness Vial Evo Ultra2, built up with a Shimano Dura-Ace Di2 R9150 groupset, will set you back €10,999 (which converts to about £9,495). Disc brake versions are available too.
The CFR (Canyon Factory Racing) version of Canyon’s Ultimate road bike has a frame that weighs just 675g, a fork that's 285g, and a complete bike weight of as little as 6.2kg.
"This incredible weight is achieved by applying quality ultra-high modulus pitch-based carbon fibres rarely seen in the industry,” says Canyon. “The material is so special, we initially had to be granted exclusive permission by the Japanese Ministry of Defence just to gain access to it.
"In order to create a structure that is strong and durable, as well as light, the ultra-high modulus fibres are blended with various other modulus and high-tensile fibres to create the complete all-round package.
"This layup is then applied to moulds with clinical precision, ensuring minimal fibre overlap to save material and thus precious grams."
All of the above bikes are carbon-fibre, but if you’d prefer steel in your life, there are lightweight options available.
Rob English of English Cycles, based in Oregon, USA, says, “Having done a lot of hillclimb racing when I was in the UK, I got on the weight-weenie kick. For NAHBS (North American Handmade Bicycle Show) 2016 my goal was to get a steel-framed bike under 10lbs (4.5kg). I managed to do it – 9.9lbs complete with pedals!
“In the years since, this has been my primary race bike. I switched it to eTap which added a few grams, but with Enve 3.4 carbon clinchers, bottle cages and Speedplay pedals it is still under 12lbs (5.4kg). I won the Oregon Gran Fondo on it in 2018.
“The low weight is wonderful to ride and the careful tubing choices in the frame design give great performance, ride quality and durability.
“What makes this possible is the work Reynolds has done in producing the 953 tubing. This stainless alloy is incredibly strong, which allows it to be drawn down to a 0.3mm wall thickness.
“I had hoped to get the frame to under 1kg but discovered that the extra 100g is in the chainstays. The high strength of the material makes it incredibly difficult to work and draw down into that tapered shape, and Reynolds is working to try and maintain the thin wall throughout the tapered section.”
Go to the English Cycles website for a full breakdown of the sub-10lb build.
Trek says that its 2021 Emonda – available with disc brakes only – is its fastest climbing bike ever.
It features aero tubing throughout, with the top-level SLR frame weighing a claimed 698g – which is slightly heavier than the preceding model because of those deeper tubes. The difference would be larger but Trek uses a new lightweight material called OCLV 800 Series carbon.
Trek says that the flagship platform is 60 seconds per hour faster than its predecessor on flat roads, and 18 seconds per hour faster on an 8% gradient (which is what Alpe d’Huez averages).
Trek says that it used its engineering expertise and specialist software to blend weight and aerodynamics, focusing on unsteady aerodynamics because the Émonda is designed for climbing where bike speeds are typically slower than on flat roads.
Factor announced updates to its O2 VAM lightweight climbing bike last August, bringing the unpainted 54cm disc frame down to a claimed 677g.
The bike also has a new front end that sees the cables routed down through the head tube for a slight aero gain. Factor claims that this move to integrated cables has allowed it to revise the carbon layup in order to improve stiffness.
Factor uses a D-shaped steerer tube that allows the brake hoses and any electronic cabling – there are no mechanical sifting options available – to pass between the steerer and the upper bearing. This means there’s no need for a larger than normal upper bearing which would have an impact on aero efficiency.
You can have the O2 VAM fitted with Twenty wheels from Black Inc, Factor’s in-house brand. The claimed weight of the clincher version is 1,240g while it’s below 1kg for the tubular version.
Bianchi launched an updated version of its lightweight Specialissima CV road bike last October, adding disc brakes for the first time while keeping the claimed frame weight at a claimed 750g – the same as that of the existing rim brake Specialissima. The full-carbon fork has a claimed weight of 370g.
Bianchi says that the Specialissima CV Disc features aero improvements that have been carried over from its Oltre aero road bikes, including internal cable routing, an integrated seat clamp, and tubing that’s shaped to reduce drag.
Real weight weenies should go for the all-black finish because it saves 80g over a celeste model.
Festka says that the rim brake version of its Scalatore road bike frame weighs approximately 740g while a disc brake frame about 50g heavier.
Festka is from the Czech Republic and doesn’t have a massive presence in the UK market, although its bikes are available through Sigma Sports.
The carbon-fibre Scalatore frame is compatible with both mechanical and electronic shifting and is matched to a Columbus Futura fork.
Festka gives you the option of custom geometry, custom colours, and an integrated seatpost if you want one.
Giant says that its 2021 TCR bikes are lighter, stiffer and more aerodynamically efficient than ever before, with the top-level Advanced SL models offering the highest stiffness-to-weight ratio in their class. We’ve reviewed the Giant TCR Advanced SL 0 Disc and can confirm that it’s a stunning bike.
The use of a new higher modulus carbon filament and updated manufacturing techniques have helped Giant reduce the frame weight of the TCR Advanced SL Disc to 765g and the fork to 330g, despite changes to tube shapes designed to improve aerodynamics.
Giant has also cut weight on things like the paint and the clamp at the top of the integrated seatpost. It has even lopped 9g off the headset’s top cap. It all counts!
The Wilier Zero SLR’s frame (medium, in the lightest finish) has a claimed weight of 780g (+/-5%) while the fork comes in at 340g (+/-5%).
Wilier reckons that the Zero SLR's stiffness-to-weight ratio is significantly higher than that of any bike it has previously released. A large part of that is said to be down to the fibres used in the frame's construction.
"For the Zero SLR we selected the highest quality fibres, calling the blend HUS-Mod: this composition is qualitatively superior to any previous type of material [we have] used," says Wilier.
"In addition to the HUS-Mod carbon, we also included a highly resistant multi-directional fibre mesh to increase rigidity in every direction and liquid crystal polymer woven to improve impact resistance and vibration absorption.”
The SuperSix Evo is the lightest disc brake frame that Cannondale has ever made, weighing in at a claimed 866g for the Hi-Mod version (56cm size). The fork is 389g and the seatpost is 162g.
Rather than trying to drop weight with the latest incarnation, Cannondale set itself goals of maintaining the low weight, handling and ride quality of the previous version while improving comfort and aero performance.
Cannondale has developed a new family of tube shapes to improve aero efficiency, with heavily truncated airfoil profiles used for the main tubes.
The down tube is the same circumference as previously so the amount of material used is the same, but it is redistributed to reduce drag by as much as 30% while also increasing stiffness.
Cannondale’s Hollowgram 45 Knot wheels reduce drag further, as does the Knot integrated handlebar and stem.
Scott claims a frame weight of 850g for its disc brake-only Addict RC, with 360g for the fork.
Like many other lightweight road bikes introduced over recent years, the latest Addict RC has a focus on aerodynamics and integration. It features a one-piece Syncros Creston iC SL Carbon combined handlebar and stem which internally routes brake hoses and gear cables/wires directly into the frame. The cables enter the front of the enlarged head tube and then go into the down tube to continue their journey.
Scott calls this new head tube and fork steerer tube the “Eccentric Bicycle Fork Shaft” and it involves a headset bearing that provides just enough space for cables, wires and hydraulic hoses to pass.
Scott’s own patented airfoil tube shape is used for the down tube, head tube, seat tube, seatpost and seatstays.
Helping to keep weight down, the seat clamp weighs just 12g.
The R5 is an 'all-rounder' intended to excel in all situations, from the slopes of Alpe d'Huez to the cobbles of Paris-Roubaix.
The original R5 was developed off the back of the made-in-California RCA project, which developed 650-700g frames. The latest R5 isn't as light as it used to be, Cervelo claiming 831g for the disc frame.
Add another 18g for the rim brake version – yes, the disc frame is lighter. Cervelo is keen to emphasise that the stiffness-to-weight ratio has shot up on the latest version of the R5.
We found the R5 frame to be very stiff when we reviewed it, and couldn’t detect much flex during powerful sprints or when surging up steep climbs.
It’s not the smoothest bike out there but the handling is great.
Mat has been in cycling media since 1996, on titles including BikeRadar, Total Bike, Total Mountain Bike, What Mountain Bike and Mountain Biking UK, and he has been editor of 220 Triathlon and Cycling Plus. Mat has been road.cc technical editor for over a decade, testing bikes, fettling the latest kit, and trying out the most up-to-the-minute clothing. We send him off around the world to get all the news from launches and shows too. He has won his category in Ironman UK 70.3 and finished on the podium in both marathons he has run. Mat is a Cambridge graduate who did a post-grad in magazine journalism, and he is a winner of the Cycling Media Award for Specialist Online Writer. Now pushing 50, he's riding road and gravel bikes most days for fun and fitness rather than training for competitions.