Road bike wheels: 8 models with carbon spokes in the test

Short & sweet

Classically spoked wheels with carbon spokes are coming into focus: they are no longer as expensive, yet are light and torsionally stiff. However, the more expensive, bonded models such as Lightweight still represent the technical optimum; at least Mavic's Cosmic Ultimate is an exciting and more affordable alternative to the classic from Friedrichshafen. Lightweight fans will be interested in the new One-K brand, which surprises with a sensational concept.

Road bike wheels with carbon spokes in the test

When the designers Rudolf Dierl and Heinz Obermayer developed a carbon spoked wheel for racing bikes 30 years ago, it was a sensation. The rim, hub and spokes of the lightweight wheels, as they were later called, were firmly laminated together and far superior to conventional designs: They combined low weight and maximum stiffness in a way that could not even begin to be achieved with the aluminium rims and steel spokes that were common at the time.

In addition, the high rim was aerodynamically favourable; if you wanted to achieve this with aluminium at the time, it meant a considerable increase in weight.

Exorbitant price

At the latest with the first prominent sporting successes - in 1996 Johan Museeuw became road world champion with the new wheels and Bjarne Riis won the Tour de France with them - they became so popular with professionals and amateur cyclists alike that demand could not be satisfied for years. Only the exorbitantly high price and the limited repair options prevented the design principle from becoming widespread.

Three decades later, the Lightweight wheels are still built according to a similar principle, mainly by hand, under the professional aegis of the Carbovation Group in Friedrichshafen. To this day, they are regarded as the epitome of what is technically feasible, even if their lead in terms of weight has diminished over the years. And to this day, they are an example of racing bike technology that has become luxury: the top model "Obermayer", named after one of the inventors, now costs 6505 euros.

But several manufacturers are shaking the throne of the lightweight construction pioneer and want to make the light-footed riding experience of a carbon spoked wheel accessible to a wider audience at more favourable prices.

Lightweight has to prove itself against seven new wheelsets, all with carbon rims and spokes, in our extensive comparison test. These include five classically spoked models and two new manufacturing concepts. Back in 2006, Mavic introduced the Cosmic Ultimate, a wheel similar to the Lightweight, which will be relaunched in 2023. TOUR was able to test it exclusively before the official market launch.

The French go to extreme lengths to achieve the optimum combination of low weight, high rigidity and good aerodynamics. The wheels are also predominantly handmade in France and, although not a bargain at 3900 euros, they are significantly cheaper than their counterparts from Friedrichshafen.

We are also exclusively testing a product with a completely new approach for the first time: One-K, a spin-off from the Technical University of Kaiserslautern, weaves connected fibre strands in a star shape around shaped pins on the hub flange and special titanium nipples, which are inserted into a standard Duke aero rim.

>> Buying advice on wheels: A guide

Well under 2000 euros

The new design aims to break all weight records and is even more affordable with prices starting at 2200 euros. Chinese suppliers are also entering the market with carbon spokes that can be combined with commercially available rims. One of these products seems so convincing that several suppliers are using it: Cadex, Hunt, Newmen and Storck all use spokes from the same manufacturer, with minor variations.

The wheels require special hubs, but can be classically centred and the spokes replaced individually. The properties of the wheel can be influenced by the interplay of the number of spokes, spoke crossing and tension. They are also inexpensive compared to a lightweight wheelset: some candidates cost well under 2000 euros.

No stretching, more tension

Michael Grätz, head of the German brand Newmen, is building up a European sales organisation for these spokes under the brand name Vonoa and explains further advantages of the material compared to classic steel spokes: "Relatively speaking, carbon is not only lighter, but also stiffer. This means that the wheels are more stable, or conversely, I need about three spokes less for comparable stiffness," he reports. Because carbon spokes do not stretch, they can withstand higher tension. In addition, the durability of the wheels is said to be better because carbon, unlike steel, does not fatigue.

Road bike wheels: New weight record

Our extensive laboratory tests clarify whether the wheels constructed in this way are technically comparable to the permanently bonded Lightweight designs. The first thing we look at is the weight, because wheels are a popular and extremely efficient tuning measure.

It turns out that carbon spokes can make the wheelsets a good 100 grams lighter than comparable designs with steel spokes. Some of the candidates actually come close to the current lightweight model (1247 grams for front and rear wheel); Storck and the flat Cadex only just miss the mark. This is because the rims have also become lighter, like Giant's hookless construction, which characterises all Cadex wheels.

Light but also stable?

Conversely, the lightweight road bike wheels gained some weight with the switch to disc brakes and tubeless tyres - in relative terms, significantly more than the classic designs.

The full carbon wheels are therefore no longer unrivalled in terms of weight - and are even overtaken in this test: Mavic's new Cosmic Ultimate is just as heavy; the extravagant wheels from K-One outshine everything that has gone before: with a set weight of just 947 grams, 300 grams less than the full carbon models, they are the new kings of lightweight construction. Such low weights have not been possible since the departure of rim brakes and tubular tyres.

But are these wheels also stable? One indication of this is the lateral stiffness, i.e. the deformation of the wheel under lateral load. This is where the One-K has to score points: With a moderate lateral load of 100 newtons on the rim, the wheels give way by around 3 millimetres. In the saddle, this means a slightly "doughy" ride feel and less steering precision, especially for heavier riders, and the feedback from the wheel is less direct.

Stabilisation by rim possible

Nevertheless, the light version of the model tested here can be stabilised with slightly heavier rims; the permissible system weight then also increases from a meagre 95 to a reassuring 125 kilograms.

The Lightweight wheel is completely different: with large-area glued spokes and wrapped spoke crossings, the front wheel in particular stands like a charm: the deformation under the same load is not half as much, only 1.4 millimetres. The competitors do not achieve these stiffness values; Mavic and Cadex nevertheless achieve a very good result in this discipline, the rest of the field a good to average result depending on the number of spokes and build quality.

Similarly good aerodynamics

All wheels also had to prove themselves in the TOUR aerodynamics test in the GST wind tunnel. As the rims and spokes of most of the candidates differ only slightly, the values are quite close to each other. Small surprises are the good performance of the comparatively flat Cadex wheels at 36 millimetres; the now outdated, tapered rim shape from Lightweight also cuts through the wind well. The aero winner with a small lead of 2 watts is the 50 millimetre high Cadex wheels with flat aero spokes.

The model from One-K brings up the rear, which is probably due to the rather voluminous spoke nipples on the rim. However, the gap to the best is a manageable 5 watts.

The question remains as to whether wheels with carbon spokes are also suitable for everyday use. One thing is clear: the material reacts sensitively to external influences such as impacts. Caution is required during transport in particular, and the spokes should be checked carefully for damage after falls. The advantage of the classic spoked versions is that spokes can be replaced individually.

However, the manufacturers all point out that servicing should only be carried out by the manufacturer itself. The wheels from Lightweight and Mavic, which cannot be easily repaired, should win the trust of customers through generous guarantees and accident replacement regulations.

Test winner under pressure

From a technical point of view, Lightweight once again wins the test. The wheels benefit from the fact that they are unrivalled in terms of stiffness. But the result is close. With the new Cosmic Ultimate, Mavic has put together an interesting package, on a par with the German competition in terms of weight and aerodynamics, with very good stiffness values and a clear price difference.

If you haven't missed anything in classic aero wheels so far, you should take a look at the new models with carbon spokes. They promise a lot of weight savings at prices that are barely higher than comparable wheels with steel spokes - this applies in particular to the models from Newmen and Storck.

Road bike wheels with carbon spokes: The trick with the rope

One of the biggest technical challenges with carbon spokes is the connection between hub and rim, because the joints have to withstand high tensile forces. Large-area lamination, as used by Lightweight, has proved successful, which, however, limits the rim shape and is incredibly complex to manufacture.

Mavic uses contiguous, opposing spokes for the Cosmic Ultimate. The fibres are positively connected to an aluminium insert on the rim side, which is supported over a large area in the rim base. The closed tyre seat is only laminated on after the rim and spokes have been connected; the spokes are inserted into pre-milled grooves in the flange on the hub and laminated in.

One-K weaves a long fibre strand in a star shape around metal hubs and spoke nipples. On the hub flange these are simple pins, on the rim they are complex moulded parts that can be screwed into the nipple seat of standard rims and also tensioned. The fibres form loops at the connections that can withstand high tensile forces.

The spokes from Cadex, Hunt, Newmen and Storck have an aluminium end piece with an external thread on each side. These are first threaded over the not yet hardened fibre strand, then the ends are thickened by wrapping them with carbon threads. The end pieces are then pulled onto the conical end and pressed with 3000 Newton.

Road bike wheels - How TOUR tests

>> Aerodynamics

Measurement of air resistance in the GST wind tunnel in Immenstaad. The wheels have identical tyres (Continental Grand Prix 5000 S, 25 millimetres) and are each measured in a complete bike (Canyon Ultimate Disc, built in 2018), on which a pedalling leg dummy sits.

The continuous measurement covers an angle of attack of +/-20° at 45 km/h, as caused by crosswinds. The high speed is used to resolve small differences; the effects are transferable to lower speeds. The results at the different angles are weighted differently according to their probability in medium winds (10 km/h) and summarised to a wattage.

>> Crosswind stability

Measured in the GST wind tunnel using a special scale that determines the forces that can be felt in the steering when the airflow is at an angle. Here, the wheels sometimes differ more than in terms of air resistance.

>> Mechanical properties

Weights and stiffnesses are calculated in the TOUR laboratory (more about the TOUR test procedure) recorded. The wheels are weighed without accessories (e.g. tubeless valves), but with rim tape if required. The stiffness test is carried out with a lateral load of 100 Newtons on the outer diameter. Stiff wheels steer more precisely and generally cause less trouble; they can withstand higher loads.

>> concentricity

Is measured after an overload test with a lateral load of 300 newtons. Vertical and lateral runout of the front and rear wheels are taken into account in equal measure.

>> Acceleration

The mass distribution of the wheels is determined with an inertial measurement device and calculated with the weight to give the energy required to accelerate both wheels from 0 to 30 km/h.

Eight road bike wheels with carbon spokes tested

Cadex 36

• Price per set: 2700 Euro >> available here

• Variants: Shimano
• Scope of delivery: Rim tape, wheel bags, tubeless valves
• Warranty, other: 2 years, crash replacement, racing exclusion
• Driver weight limit: k. A.
• Number of spokes f. / h.: 21 / 24
• Rim W x H / inside width: 26 x 36 / 22 millimetres
• Aerodynamics at 45 km/h: 221 watts
• Weight v. / h.: 590 / 710 grammes
• Lateral stiffness f. / h.: 59 / 49 N/mm

Road bike wheels - TOUR review

• Aerodynamics (25%) Grade 1.7
• Weight f. + h. (25%) Grade 2.3
• Front lateral stiffness (10%) Grade 1.3
• Rear lateral stiffness (10%) Grade 2.0
• Concentricity (10%) Grade 2.4
• Acceleration (10%) Grade 2.3
• Crosswind stability (10%) Grade 2.3

Overall grade: 2.0

Conclusion: Set of carbon spokes from the Giant wheel brand. Light and stable, also aerodynamically good for the height. Wide, hookless rim, ceramic bearings. Also available with a height of 42 and 65 millimetres. Questionable regulation for race exclusion.

Cadex 50 Ultra

• Price per set: 2800 Euro >> available here

• Variants: Shimano
• Scope of delivery: Rim tape, wheel bags, tubeless valves
• Warranty, other: 2 years, crash replacement, racing exclusion
• Driver weight limit: k. A.
• Number of spokes f. / h.: 21 / 24
• Rim W x H / inside width: 30 x 50 / 22 millimetres
• Aerodynamics at 45 km/h: 217 watts
• Weight v. / h.: 609 / 747 grammes
• Lateral stiffness f. / h.: 57 / 49 N/mm

Road bike wheels - TOUR review

• Aerodynamics (25%) Grade 1.3
• Weight f. + h. (25%) Grade 2.7
• Front lateral stiffness (10%) Grade 1.7
• Rear lateral stiffness (10%) Grade 2.0
• Concentricity (10%) Grade 2.0
• Acceleration (10%) Grade 2.3
• Crosswind stability (10%) Grade 2.7

Overall grade: 2.1 hh

Conclusion: In contrast to other heights, the 50-millimetre version has significantly wider aero spokes, which Cadex uses exclusively. Best aerodynamics in the test field, slightly heavier, otherwise without weaknesses. Questionable race exclusion rule.

Hunt 48 Limitless UD Carbon Spoke

• Variants: Campagnolo, Shimano, SRAM XDR
• Scope of delivery: -
• Warranty, other: 3 years, crash replacement
• Driver weight limit: 109 kilogrammes
• Number of spokes f. / h.: 18 / 20
• Rim W x H / inside width: 29 x 44 / 20 millimetres
• Aerodynamics at 45 km/h: 219 watts
• Weight v. / h.: 601 / 752 grammes
• Lateral stiffness f. / h.: 40 / 41 N/mm

Road bike wheels - TOUR review

• Aerodynamics (25%) Grade 1.7
• Weight f. + h. (25%) Grade 2.7
• Front lateral stiffness (10%) Grade 3.0
• Rear lateral stiffness (10%) Grade 3.7
• Concentricity (10%) Grade 2.3
• Acceleration (10%) Grade 2.7
• Crosswind stability (10%) Grade 2.7

Overall grade: 2.5

Conclusion: Inexpensive and fast. Few spokes, resulting in weaknesses in rigidity; concentricity no longer perfect after heavy loads. Ceramic bearings optional; many options for rim heights and freewheels.

Lightweight Obermayer EVO

• Price per set6505 Euro

• Variants: Campagnolo, Shimano, SRAM XDR
• Scope of delivery: Rim tape, wheel bags, tubeless valves
• Warranty, other: 5 years, crash replacement
• Driver weight limit: 100 kilogram system weight
• Number of spokes f. / h.: 20 / 20
• Rim W x H / inside width: 48 x 24 / 18 millimetres
• Aerodynamics at 45 km/h: 220 watts
• Weight v. / h.: 571 / 676 grammes
• Lateral stiffness f. / h.: 70 / 54 N/mm

Road bike wheels - TOUR review

• Aerodynamics (25%) Grade 1.7
• Weight f. + h. (25%) Grade 2.0
• Front lateral stiffness (10%) Grade 1.0
• Rear lateral stiffness (10%) Grade 1.3
• Concentricity (10%) Grade 1.6
• Acceleration (10%) Grade 2.0
• Crosswind stability (10%) Grade 2.3

>> Overall score: 1.7 and thus TOUR test winner

Conclusion: Classic, handmade in Germany. Elaborate design with laminated spokes. Unrivalled stiffness, resulting in a very direct ride feel. Long guarantee, repair option. Test winner; unfortunately extremely expensive.

Mavic Cosmic Carbone Ultimate 45

• Price per set: 3900 Euro

• Variants: Campagnolo, Shimano, SRAM XDR
• Scope of delivery: Wheel bags, tubeless valves
• Warranty, other: Lifetime, Crash Replacement
• Driver weight limit: 120 kilogrammes
• Number of spokes f. / h.: 20 / 20
• Rim W x H / inside width: 28 x 46 / 20 millimetres
• Aerodynamics at 45 km/h: 219 watts
• Weight v. / h.: 569 / 680 grammes
• Lateral stiffness f. / h.: 58 / 47 N/mm

Road bike wheels - TOUR review

• Aerodynamics (25%) Grade 1.7
• Weight f. + h. (25%) Grade 2.0
• Front lateral stiffness (10%) Grade 1.3
• Rear lateral stiffness (10%) Grade 2.0
• Concentricity (10%) Grade 2.0
• Acceleration (10%) Grade 2.0
• Crosswind stability (10%) Grade 2.7

>> Overall grade: 1.9

Conclusion: New edition of the full carbon wheel introduced in 2006. Handmade in France. Very light, aerodynamically good and stiff enough for high demands. Lifetime guarantee and high weight limit.

Newmen Advanced SL R.50 Streem CS

• Price per set: 1790 Euro

• Variants: Shimano, SRAM XDR
• Scope of delivery: Rim tape, Tubeless valves, milk
• Warranty, other: 3 years, crash replacement
• Driver weight limit: k. A.
• Number of spokes f. / h.: 21 / 21
• Rim W x H / inside width: 50 x 25 / 18 millimetres
• Aerodynamics at 45 km/h: 219 watts
• Weight v. / h.: 628 / 742 grammes
• Lateral stiffness f. / h.: 54 / 50 N/mm

Road bike wheels - TOUR review

• Aerodynamics (25%) Grade 1.7
• Weight f. + h. (25%) Grade 2.7
• Front lateral stiffness (10%) Grade 2.0
• Rear lateral stiffness (10%) Grade 1.7
• Concentricity (10%) Grade 1.7
• Acceleration (10%) Grade 3.0
• Crosswind stability (10%) Grade 2.3

>> Overall grade: 2.2

Conclusion: Slightly heavier than the competition, but very inexpensive and stiff, even at the rear. Relatively narrow rim; variants from 38 to 80 millimetres rim height available, also individually.

One-K RD-Ultimate

• Price per set: 2799 Euro

• Variants: Shimano, SRAM XDR
• Scope of delivery: Wheel bags
• Warranty, other: 2 years
• Driver weight limit: 95 kilogramme system weight
• Number of spokes f. / h.: 24 / 24
• Rim W x H / inside width: 28 x 36 / 22 millimetres
• Aerodynamics at 45 km/h: 222 watts
• Weight v. / h.: 433 / 514 grammes
• Lateral stiffness f. / h.: 35 / 34 N/mm

Road bike wheels - TOUR review

• Aerodynamics (25%) Grade 2.0
• Weight f. + h. (25%) Grade 1.0
• Front lateral stiffness (10%) Grade 4.3
• Rear lateral stiffness (10%) Grade 3.7
• Concentricity (10%) Grade 2.5
• Acceleration (10%) Grade 1.0
• Crosswind stability (10%) Grade 1.7

>> Overall grade: 2.1

Conclusion: Newcomer with an independent concept. Rims supplied by Duke from Asia, hub production and assembly in Germany. Spectacularly light, also aerodynamically passable, but weaknesses in stiffness.

Storck Zeitjaeger Platinum 45 R

• Price per set1999 Euro

• Variants: Shimano, SRAM XDR
• Scope of delivery: -
• Warranty, other: 2 years
• Driver weight limit: 110 kilogram system weight
• Number of spokes f. / h.: 21 / 24
• Rim W x H / inside width: 29 x 45 / 21 millimetres
• Aerodynamics at 45 km/h: 220 watts
• Weight v. / h.: 567 / 712 grammes
• Lateral stiffness f. / h.: 46 / 49 N/mm

Road bike wheels - TOUR review

• Aerodynamics (25%) Grade 1.7
• Weight f. + h. (25%) Grade 2.3
• Front lateral stiffness (10%) Grade 3.0
• Rear lateral stiffness (10%) Grade 2.0
• Concentricity (10%) Grade 2.5
• Acceleration (10%) Grade 2.0
• Crosswind stability (10%) Grade 2.0

>> Overall grade: 2.2

Conclusion: Affordable and lightweight all-rounder, good aerodynamics, less sensitive to crosswinds. Lateral stiffness only average, especially at the front, therefore not recommended for heavy riders.