It's very easy to spend a fortune on saving a few grams, and many of us want the lightest and fastest road bike we can afford. Fortunately, there are many lightweight cycling products on the market as bike brands set out to showcase their proficiency in material science and engineering. Here are some of the lightest, money-no-object bike frames and components we could find to inspire your ultimate lightweight build.
As a general trend, bikes have become a little heavier in recent years due to the adoption of disc brakes and electronic groupsets.Though, on the whole, the best road bikes are still impressively light, and if the UCI's bike weight limit of 6.8kg doesn't apply to you, there are still plenty of very light road bikes and components on the market.
If you're wondering where the inspiration for this article came from... well we already have a guide to the lightest road bikes, however that consists of bikes that you can buy 'off the peg'. As we've alluded to above, stock bikes aren't quite so light nowadays due to the adoption of disc brakes and aero everything - so due to popular demand, we've put this round-up together to show just how much lighter you can go by building up a lightweight dream machine yourself.
So our suggestions remain somewhat accessible, we're sticking to frames and components that are available to buy. That means we haven't included anything fully custom without a recommended retail price. Of course, if you know of makers or experts who can knock up parts that are even lighter than the options below, give them a mention in the comments.
You may also notice some of our picks are eye-wateringly expensive, but that comes with the territory when you're looking for the most exotic lightweight parts around. If you want some more affordable, real-world suggestions you can check out our feature on how to make your bike lighter, and it's also worth noting that because a lot of these products are a few years old now, you could potentially find them much cheaper secondhand.
You'd struggle to build a full bike out of these parts as some of our selections won't fit together, but choosing any of them and speccing alternative lightweight components that match will get you off to a good start...
A bike's weight isn't the be-all and end-all, often being trumped by aerodynamics or comfort in the real world, but that doesn't stop us from wanting the lightest machine we can afford.
Specialized claims the S-Works Aethos is the lightest frame out there, weighing just 585g (size 56cm), with complete bikes weighing from 5.9kg. Although the Aethos frame is UCI-approved it isn’t designed for racing, being well under the 6.8kg minimum weight limit - which didn't stop Deceuninck–Quick-Step's Kasper Asgreen using it at the Tour de France in 2021.
The front end isn't integrated leaving the brake hoses exposed, and there's a lack of aero tube shapes - but what the Aethos lacks in aero, it certainly makes up for in weight, or lack of it.
Specialized says this bike is aimed at riders who prioritise handling and ride quality above aerodynamics, and who want the ultimate high-performance road bike unrestricted by competition rules.
Factor has unveiled a new version of its O2 VAM road bike, used by Israel-Premier Tech in this year's Tour de France.
Factor call it "the world's fastest climbing bike", coming with a frame that weighs a claimed 730g including its external seatpost. It can also be built up into a complete bike that weighs a claimed 6.2kg.
Despite being a climbing bike, the O2 VAM also includes aerodynamic features like D-shape truncated aerofoil tube profiles. Factor's aim was to develop the most aerodynamically efficient frames it could at 700g, while other bikes at this weight use predominantly round tube shapes and little or no cable integration.
if you're going full weight weenie and lightweight is your only priority, a rim brake option like the Cannondale SuperSix Evo Hi-Mod frameset could be a more cost-effective starting point than newer disc brake alternatives.
The final rim brake SuperSix that Cannondale made was the 2019 SuperSix Evo Hi-Mod, with a weight of around 777g for the frame.
Despite this being slightly heavier than the disc brake options above, complete rim brake bikes tend to be lighter than disc brake bikes due to the additional components required for disc brakes, such as the brake callipers, rotors and associated hardware.
Despite being released in 2013, SRAM's 11-speed mechanical Red groupset is still regarded as one of the lightest road bike groupsets. It's a weight weenie's favourite for combining functionality with low weight, weighing around 1,750g for the full groupset.
Current-generation 12-speed electronic groupsets are almost 1,000g heavier than SRAM Red 22. The lightest being Shimano's Dura-Ace R9200 groupset which we weighed in at 2,507g, then SRAM Red AXS coming in at 2,518g. Finally, Campagnolo's Super Record Wireless groupset is said to be 2,520g.
Engineered in Germany, THM brings aerospace engineering to the world of cycling, and has designed these crank arms entirely from carbon fibre.
The crank arms feature aligned fibres in the internal and external splines, which THM claims "reduces wear to near zero and eliminates noise".
The claimed weight is around 302 grams for standard crank arms and about 293 grams for compact options.
It fits any frame with a standard 68mm BSA shell, and is available in lengths of 170, 172.5 or 175 mm.
Recon cassettes are machined from a single piece of aluminium, which is said to produce the lightest weight possible.
Aluminium cassettes don't last as long, but they are lighter than their nickel-plated steel alternatives. Recon says their cassettes have multiple surface coatings to increase cassette life.
An 11-28t cassette is said to be 117g, which is around half the weight of the equivalent Shimano Ultegra cassette.
Your wheelset is probably one of the best places to start shedding weight, as many off-the-shelf bike builds will most likely see compromises here.
Carbon wheels are one of the most popular aftermarket upgrade options, and at an eye-watering £4,799, Princeton Carbon Works' Alta 3532 wheelset is designed for climbing, weighing in at 1,150g on the road.cc scales of truth.
You'll have noticed the unique rim shape, which is Princeton's Evolution design. It's said to create a more efficient wheelset by removing material from the inner edge of the rim. The rim depth varies between 32mm and 35mm and has an internal width of 21mm.
They are tubeless-ready and are available in both disc and rim brake versions.
AX Lightness is a German manufacturer specialising in carbon products, and its Ultra 25T wheelset has a claimed weight of just 790g for a pair, which would be a reasonable weight for a single wheel. Despite this low weight they have "outstanding stiffness and stability", AX Lightness claims.
The Ultra 25T wheelset is for rim brakes only and designed for climbing, featuring a 25mm tubular carbon rim and Extralite Cyber hubs.
Extralite's Streeters skewers are created by multiaxial 3D machining. Extralite claims this is one of the lightest pair of skewers in the world, weighing just 29g for the pair.
The levers are CNC'd aluminium, the rod is hi-grade Titanium and rubber seals are utilised where metallic springs would usually exist.
They are compatible with a standard front 100mm and rear 130mm, and are available in six colours.
Disc brake bikes are generally heavier than a comparable rim brake bike, and if you have around £600 to spare, this pair of rim brake callipers could save you a few grams.
It's claimed they are the "world's lightest road calliper set", weighing 125g for the set (minus pads) and are made from Grade 5 titanium, 7075 aluminium, and carbon fibre.
They are compatible with 30mm rims and up to 32mm tyres too.
Tubular wheel/tyre systems are impractical for most of us who don't have access to a team car with spare wheels, but remain lighter than most clincher or tubeless clincher tyres. The Elite Jet tubular tyres aren't for everyday use, designed for time trials and road races with good surfaces.
Tofu claims these tyres weigh <160g each for what would now be considered a very narrow width of 20mm. Vittoria Corsa Speed tubular tyres are said to weigh 200g (23mm).
Veloflex is a small tyre company that designs and manufactures its handmade cotton tyres in Italy.
The Veloflex Corsa Race TLR is a good tubeless road tyre for fast riding, and the casing features a whopping 350tpi (threads per inch) construction to ensure the lowest rolling resistance. There is an extra layer of "Air Lock Membrane" to help minimise air loss and under the tread there is an anti-puncture belt, the "RKB (Resilient Kinetic Belt)".
They weighed in at 219g on the road.cc scales, which is very light considering they still include an anti-puncture belt, and they are available in a width of 25mm.
Using TPU (short for Thermoplastic Polyurethane) for inner tubes is claimed to increase toughness, and reduce volume and rotating mass. While the cost might seem incredibly high for a tube, if you're looking to save weight then the grams saved per pound ratio stacks up well.
TPU inner tubes are great if you're a rider who seeks ultimate performance, and appreciates the simplicity and hassle-free installation and maintenance of a tube-type system.
We weighed the Pirelli SmarTUBE P ZERO Road inner tubes in at just 39g here at road.cc.
The Bontrager XXX carbon integrated handlebar and stem is one piece, which is said to increase strength while reducing weight by eliminating the need for bolts and material to join the two components together.
Bontrager says this handlebar and stem combination is at least 120 grams lighter than other handlebar/stems of the same material and size, with a claimed weight of 234 grams (110mm stem/42mm width).
Schmolke's TLO series uses carbon fibre prepreg. This is when carbon fibre fabrics are immersed in a still, wet plastic matrix, which is said to increase strength and results in less layers, meaning weight is reduced.
They are available in widths of 40, 42 and 44 cm (outside to outside) and are said to weigh around 145g depending on the width.
TLO Evo models are also available with optional holes for internal cable routing.
What makes this stem special? “Rather than going the simple way by holding the aluminium nuts by a half round bent plate we are using the ‘loop technology’ where the carbon fibres run fully around the aluminium inserts – allowing for full stiffness,” Schmolke says.
Weighing a claimed 81g (100mm), this stem has a 1k carbon finish and is available in 100mm to 120mm for road bike use.
Is this the lightest saddle in the world? Lightweight saddles seem to get the weight weenies a bit excited, and some cyclists will happily sacrifice seated comfort it means they can save a morsel of weight.
Selle Italia's SLR C59 saddle is the lightest in its range, and is made entirely of carbon fibre featuring the Superflow central cut-out.
Most reasonably lightweight racing saddles come in at well over 100g, but Selle Italia claims the SLR C59 weighs just 61g.
This seatpost is made of carbon fibre using bidirectional and unidirectional fabrics, with an asymmetrical laminate which is said to achieve the optimum weight with maximum resistance.
Each seatpost is said to be laminated by hand "to achieve a record weight", Darimo says. To further reduce weight, the clamping system is made of two Dyneema loops.
It has a claimed weight of 90g in a 31.6mm diameter and 400mm length, but it's not recommended for riders that weigh more than 90kg.
The Ultralight X-Rotor SteelCarbon 3 brake discs aren't exactly a completely new creation. These are in fact the third generation and have been on weight weenie mountain bike riders' wishlists for quite some time. They have been redesigned slightly, including a more rounded edge to please the UCI.
As used by UAE Team Emirates WorldTour team this season, the 140mm X-Rotor SteelCarbon 3 is said to weigh 68g, and the 160mm rotor is 80g.
The Speedplay Nano pedals are dual-sided and designed for road cycling only. They are made up of a combination of a titanium spindle and carbon fibre body in an attempt to create a lightweight, yet strong pedal.
Speedplay pedals differ to Shimano and Look systems, as most of the mechanics sit within the cleat on your shoe rather than in the pedal. This perhaps makes them an unfair comparison, as you still have a similar amount of weight in total - just less in the pedal itself.
They are said to weigh 168g for the pair.
The production version of this super skinny cage from CarbonWorks is claimed to weigh just 8g - and a few years ago at Eurobike, we saw an example that weighed under 4g (CarbonWorks guarantees each one will weigh 8g or less).
CarbonWorks claims the cage is still durable thanks to the addition of a clear coat on top of the material. Its tubular construction resembles aluminium bottle cages from the 1980s, but it's made from carbon fibre, which is considerably lighter.
Silca’s super-strong 3D-printed titanium computer mount is a totally OTT, albeit neat, way of finishing off the front end of your bike.
Silca says that it is six to 12 times stronger than aluminium, and is also said to weigh as little as 27g. It can be custom 3D-printed to your stem's width, and Silca even boasts it will improve aerodynamics, with a claimed saving of 3-6 watts compared to other mounts.
Hill climbing - that quintessentially British cycling discipline whereby the only aim is to gurn and grind up a hill as fast as you possibly can - often means that competitors go to great lengths to shed every possible gram off their bikes, so they're carrying as little weight uphill as possible. If you're aiming to build up a lightweight bike for hill climb races, there are things you can do to lighten your bike beyond spending more money if you're mechanically minded/good with a saw (we wouldn't recommend any of these hacks for riding on open roads)...
The bike above has had the drops of the handlebars sawn off for some extra weight saving. There is no bar tape either, and the drivetrain is 1x to save the weight of an extra chainring that won't be needed on a hill climb.
Other tricks include being strategic with wheel spokes, stripping the paint off frames and even drilling out parts (known as 'drillium') to save tiny bits of weight, as beautifully demonstrated by the Campag Kid in the image above.
What are your favourite lightweight bike frames and components, and is there anything even lighter out there that we've missed? Let us know in the comments section below.
Emily is our track and road racing specialist, having represented Great Britain at the World and European Track Championships. With a National Title up her sleeve, Emily has just completed her Master’s in Sports Psychology at Loughborough University where she raced for Elite Development Team, Loughborough Lightning.
Emily is our go-to for all things training and when not riding or racing bikes, you can find her online shopping or booking flights…the rest of the office is now considering painting their nails to see if that’s the secret to going fast…