The fascination of lightness: 6 lightweight road bikes from 6.5 to 6.8 kilos on test
Jens Klötzer
· 06.11.2023
We tested these six lightweight road bikes:
Click to go to the individual rating.
The topics in this test:
The test bikes at a glance
No, nobody needs a racing bike that weighs less than 6.8 kilograms. According to the technical regulations of the International Cycling Union (UCI), this weight marks the lower limit for racing bikes that are allowed to be used in competitions. Even the professional cyclists' bikes are not allowed to be lighter when they are cranking up the steepest mountains of the Tour de France. However, the fact that (even) lighter bikes are therefore not desirable is just theory. In fact, hardly any cyclist can escape the fascination that emanates from an extremely light racing bike. The beguiling feeling of climbing the mountains on a featherweight bike, as if you had suddenly got wings, is far too tempting to simply do without. Every gram of weight saved makes a bike more explosive in its acceleration and more playful in its handling - lightweight construction harbours addictive potential, especially for cyclists whose passion is the mountains.
Searching for meaning on the aero wave
These emotions are probably one of the reasons why lightweight competition bikes are still very much a part of many manufacturers' programmes. They now play a subordinate role in professional sport, where the realisation that a slightly heavier but aerodynamically faster bike is the better choice in most racing situations is becoming more and more widespread. In addition, in recent years even aerodynamically good bikes, when fully assembled, have been approaching the seven-kilo mark, which is why the choice is increasingly in favour of an aero model. For some manufacturers, a second model is becoming completely superfluous. An outstanding example of this is the brand new Specialized S-Works Tarmac SL8, which, with a weight of just 6.6 kilos (weighed without pedals and accessories) and good aerodynamics in TOUR 11/2023 The bike scored the top mark of 1.3 in our rating system because it combines the two contrasting characteristics of weight and aerodynamics in the best possible way. In race trim, i.e. including pedals and bottle cage, it should only just exceed the UCI limit, if at all.
Several new releases from renowned manufacturers in 2023 show that, despite the aero trend, there must still be a clientele for more or less uncompromisingly light racing bikes today. Bianchi relaunched its Specialissima lightweight model, Canyon revised the Ultimate and launched a weight-optimised CFR version. The British-Taiwanese brand Factor used the big stage of the Tour de France to present its new O2 VAM mountain bike. In our comparison test, the three newcomers are pitted against three well-known lightweight bikes from Giant, Trek and Storck. The main aim of the sextet is to show whether special lightweight bikes still have a raison d'être in the age of the Tarmac SL8. The aim is not only to prove that they are ahead in terms of weight. Because all manufacturers also advertise aerodynamic optimisation of their framesets for this species, we also tested their promises in the wind tunnel.
The pursuit of lightness
A look at the history of road bike development shows that the quest for lighter materials has always been a key driving force. For as long as there have been racing bikes, manufacturers have been trying to wring gram after gram out of their designs, sometimes at seemingly ludicrous expense. The lightweight construction era reached a temporary peak around ten years ago, when lightweight rim brakes were still standard and carbon processing was already well advanced. Some bikes managed to show a five before the decimal point on the scales - without any significant loss of stability, features or function. The extreme diet did not provide a competitive advantage in sport due to the aforementioned minimum limit, and some professional bikes even had to be artificially weighted down. Only a few solvent amateur athletes, who were prepared to fork out absurdly high sums for the super-light bikes, were able to benefit from this.
Nobody can beat the 6.8-kilo mark
Unfortunately, the pricing of the lightweight kings has not changed since then. With today's obligatory disc brakes, however, weights of less than six kilograms are a distant prospect. Reinforced frames and forks and heavier components have catapulted the weights upwards, in addition to the trends towards integrated cables, wider tyres and more aerodynamic frame shapes. The 6.8-kilo mark has become a theoretical limit, as it can hardly be undercut with current technology. Manufacturers are trying to counter this development with excessive use of carbon fibre. As with the wheels from Giant and Factor, the use of carbon fibre even extends to the spokes.
Nevertheless, none of our current test candidates can break the 6.5-kilo mark, as it is clearly not possible to achieve a lighter weight with today's technical requirements. This means that the 6.8 can be comfortably achieved, but nothing more. A look at the bare frame weights shows that there has been no standstill since the disc caesura. With weights of around 800 grams, as achieved by Canyon and Storck, the designs are back at the level of light rim brake bikes with largely round tube cross-sections. The Giant TCR and the Trek Émonda also belong in this league if you factor out the additional weight of the integrated seat dome, which makes a classic seat post superfluous. The fact that the Émonda takes last place in the weight ranking at 6.8 kilograms is largely due to the integrated handlebar combo, as the wheels and gear group can be ruled out as heavyweights.
It is pleasing that the low weight does not have a detrimental effect on the function and riding characteristics of any of the participants. Even a bike with comparatively low stability like the O2 VAM from Factor is still stiff enough for most riders and applications. On high-speed descents, however, the very stiff bikes from Canyon and Giant feel noticeably better on the road.
Full-size wheels
There is also no reason to complain about the suspension comfort on the saddle, the bikes absorb bumps extremely well. The "heaviest" frame in the test is the Bianchi Specialissima. However, you shouldn't worry about the extra 100 grams compared to the competition, especially as the bike can make up for the weight disadvantage in other areas. The unusual design also scores points in the wind tunnel: Even with the relatively flat standard wheels, together with Canyon and Storck, it belongs to the faster group in the comparison, requiring around 220 watts of pedalling power at 45 km/h to overcome the air resistance in the TOUR measurement in the GST wind tunnel. Equipped with the faster reference wheels, the Specialissima can even pull away from the competition. Behind the trio are Trek, Factor and Giant, with only the Giant TCR's frameset being the bigger brake. Factor and Trek could catch up with the front group with faster wheels.
However, the bikes are no match for a top all-rounder like the Specialized Tarmac. Its achieved value of 209 watts - at a comparable weight - is far beyond the realms of possibility for lightweight bikes. In view of the data situation and ever lighter aero models, the arguments in favour of a special lightweight category are becoming weak. For solvent enthusiasts, they would have to become even lighter. Forbidden light.
Short & sweet
Despite lighter frames and components, manufacturers have not yet succeeded in pushing the weight of road bikes with disc brakes well below the UCI limit. It is reasonable to assume that the "only" lightweight road bike will eventually die out, at least for use by the broad mass of cyclists; most road cyclists today expect a lightweight and streamlined bike, as ridden in professional sport and continuously developed by most manufacturers.
Details that caught our eye:
The test results at a glance
How Tour tests
How to read the TOUR test chart
In order to visualise the characteristics of the test bikes with their various functional and dynamic characteristics, the individual descriptions of the test bikes are supplemented by a six-axis diagram. This allows all the strengths and weaknesses of the models to be recognised at a glance. The characteristics on the individual axes are made up of measured values and subjective impressions of the test riders. The larger the blue area, the better the wheel in question.
Overview: Even more lightweight road bikes
Cube Litening Air SLX
The Cube Litening Air may not look like a classic lightweight model with its aerodynamically shaped seat tube, but the frame easily breaks the 900 gram mark, the fork is 370 grams, so the Cube can compete with many lightweight models from illustrious brands. Reason one for mentioning it here is the complete bike weight of just 6.6 kilograms, which is communicated for the top SLT version with Dura-Ace groupset. The manufacturer's claim is credible insofar as our test bike with Ultegra equipment was already well below the seven-kilo mark when it was launched. The Newmen wheels with carbon spokes, which are supplied exclusively for Cube, play a major role in this. The second reason is the aggressive pricing: for 7,999 euros, which is the price of the top model, you have to heave at least a kilo more out of the shop with other manufacturers.
- Price: 7,999 euros
- Weight: 6.6 kilos
Orbea Orca
With the recently introduced Orca generation, Orbea also wants to compete for the lightest road bikes. Until we get a model into the TOUR test lab, we will have to make do with the manufacturer's promises: The frame of the high-quality OMX series should weigh less than 750 grams, and a complete weight of 6.7 kilograms should be possible when assembled. Interested parties will have to shell out a five-figure sum for this goal, but then a Shimano Dura-Ace power meter will also be on board. The price can be varied almost at will, as the components can be customised in an extensive configurator. Buyers also have a number of colour options to choose from. However, the cheaper OMR frame, which is available in versions up to around 6,000 euros, is no longer a real lightweight construction at a good 1,000 grams.
- Price: 10,999 euros
- Weight: 6.7 kilos
Scott Addict RC Ultimate
The classic Addict RC is available in two exciting versions for lightweight fans. The RC Pro already boasts a frameset weight of 1,300 grams (frame: 900 grams in size 56). With exquisite standard equipment including Shimano's Dura-Ace gears and Zipp 303 wheels, the seven-kilo mark is within reach. In return, you get a top-equipped, razor-sharp racer at professional level, with impeccable handling and clever integration solutions. On the top model, the Addict RC Ultimate, the designers have managed to reduce the weight of the frame and fork by a further 40 grams; with SRAM Red and Zipp 353 NSW, the standard weight is 6.7 kilos. However, the manufacturer demands a proud price for this: Scott wants 16,000 euros for the flagship model, while the Pro costs a relatively modest 9,500 euros.
- Price: 15,999 euros
- Weight: 6.7 kilos
Specialised S-Works Aethos
Pretty much unchallenged since its launch in 2020, the Specialized S-Works Aethos has won the trophy for the lightest production bike - at least since racing bikes have had (heavier) disc brakes instead of rim brakes. The puristically designed frame weighed a spectacular 618 grams on the TOUR scale in size 56, while the fork weighs less than 300 grams. Aerodynamic performance and integration of any kind were dispensed with in favour of weight, making the Aethos one of the few high-end racers with a classic look, standard-sized stem and seatpost and brake lines running freely in front of the head tube. With the Roval Alpinist wheels and Dura-Ace groupset, the scales remain at an incredible 6.2 kilograms, for which Specialized charges 14,000 euros. However, the Aethos Pro, which costs 9,000 euros, should also stand up well to the competition: A frame weight of around 700 grams and a complete weight of less than seven kilograms are promised for the bike with Shimano's Ultegra equipment.
- Price: 14,000 euros
- Weight: 6.2 kilos
Jens Klötzer
Editor
