Tester
- Age: 25
- Physical attributes:
I’m a skinny guy (60-62kg) who isn’t particularly well muscled. As you can see from my power profile below (which will be added tomorrow), I am not an explosive or powerful rider, rather
for what little strength I have, I do ok in the 5-20minute range (Cat 2).
Previous (relevant) wheelset experiences
- DA 9000 C24 tubs, Campagnolo Bora Ultra II, Easton EC90 SL, Hed Jet 6 FR,
- Test bike: Bianchi Oltre XR2 (review to come)
Construction
Mavic’s Cosmic Carbone Ultimate fall into a select subset of wheelsets that employ an integrated carbon rim-to spoke construction. The intent of this design is twofold. First, carbon spokes bonded to a carbon hub shell reduces weight over conventional alloy spoke/hub designs. Second, high modulus carbon spokes are more rigid than their alloy counterparts, the upshot of which is a laterally and vertically stiffer wheel. Clearly, this design is effective at creating an extremely stiff wheel as has been demonstrated by:
http://www.rouesartisanales.com/article-23159755.html
There is also a thorough description of the construction here:
http://www.rouesartisanales.com/article-6936793.html
A consequence of this integrated carbon construction is that spoke breakages are allegedly irreparable. However, in the event of a spoke breakage I think it would be worth taking the wheel to a carbon repair company such as ‘paintmybike’ to see if they cant help you out.
Weight
Mavic claim the raw weight of the wheels alone is approximately 1185g. For a tubular wheelset with a 40mm profile, this is competitively light. However, compared to similarly designed wheels such as Lightweight, Reynolds RZR or Corima MCC+, CCU’s are relatively fat losing out ~100-200g respectively.
Ride quality
The immediate sensation when you hop on your bike is that of lightness. My Oltre XR2 slimed from 7.3kg with the Hed Jet 6 FRs to 6.6kg with the Ultimates – respectably light. The only way to describe the contrast from normal heavy training wheels to ultralight tubular wheels is the sensation of the absence of something on your bike. With the heavy Heds, the bike feels planted and firm-footed on the ground with the wheels feeling like an integrated extension of the frame. In contrast, with the Ultimates, as you spin the bike up out of the saddle, it more so feels like just a frame floating through the air. Naturally, this is just a colourful example.
An additional benefit of the low rolling weight is an increase in the nimbleness of the handling. There is such a drastic improvement in cockpit control that when I first got the wheels I oversteered into some corners and had to make quick adjustments to prevent a crash. Don’t mistake this increased manoeuvrability for twitchiness, in contrast, it is easier to pick lines and hold them. No doubt, this is a combination of the low weight of the front wheel as well as its lateral stiffness.
Further to this fluid sensation of lightness is the incredible stiffness of the wheels. Hard accelerations out of saddle are perhaps this wheelsets principal strength. Initially, big efforts are rewarded by an immediate surge forward combined with the feeling that there is absolutely no lateral deflection of the wheels.
Driving along in the saddle, this sensation of immediacy and responsiveness disappears and they feel much like any other wheelset. With a thick, smooth sensation from the hubs, the light rims provide a muted, wooden driving sensation. Given these qualities, over a smooth surface the wheels feel surprisingly unremarkable – they silently hum along and do not contribute much to the overall sensation of the frame.
Despite the 40mm deep aero section, the wheels do not feel particularly aero. Campy Bora’s and especially the Hed Jet 6 FR’s feel like they roll along with greater ease and feel as though they hold their speed with greater ease. To be fair, both wheelsets are 10 and 20mm deeper respectively. For the duration of my test, the wheels were never unduly perturbed by cross winds. They were twitchier than the Heds, but they are not difficult to control.
A downside the immense stiffness of the wheels is that they are incredibly harsh over rough road surfaces. For the duration of my test, I ran either 21mm Vittora Corsa EVO KS or Tufo S3 lite tubs at ~90psi. This was fine up to ~100mins in the saddle. However, by the end of longer rides I felt more fatigued from my core muscles having to provide additional compensation for all the rattling coming through the frame. Adding insult to injury, after a long ride, these wheels literally bouncy over larger bumps in the road which is notably more jarring than other wheelsets I have tried. One way to reduce this harshness would be to put wider i.e. 24-25mm tires on. Alternatively, if your frame is not very stiff, these wheels could breathe a bit of life into the frame.
Hubs
The hubs are biggest weakness of this wheelset. Rolling along, they feel very smooth yet concurrently beset by a subtle friction. This sensation of sluggishness is most evident when you swap between wheelsets. For example, Dura-ace 9000 C24Ts allow the bike to roll along with tangible ease, as if you’re skating over ice. Alternatively, the Hed Jet 6 FR’s provide an immediate sensation as if you are riding with a tail wind (even if you don’t). As you acclimatise to the wheelset, you notice this ‘friction’ less and less and the hubs just feel a thickish smoothness. The A word to describe this feeling of thick smoothness is constraint. The lack of eagerness to fluidly role along is particularly evident with a hard driving pace. Rather than hold their speed as you increase the tempo, the wheels feel like they just want to slow down. Whether the wheels are objectively subject to high hub frication is uncertain, rather, they just feel slow. This creates a somewhat paradoxical ride quality. On the one hand, due to the low weight and the stiffness, the wheels initially feel very fast, but then once they are rolling along, they feel comparatively slow. The sensation of slowness is a big psychological blow particularly from the perspective of trying to dig deep at the end of a race or during a hard interval. The feeling of inhibition does not promote the will to dig deep if that makes sense.
You may be thinking, “There must be something wrong with your hubs!” I assure you, they have been checked over by a mechanic are in prime working condition. To conclude, they are just inferior hubs to the competition.
Breaking
Dry weather braking under normal riding conditions was rather impressive (using SwissStop Black Prince pads). In particular, modulation rivals most run of the mill alloy clinchers. Despite the fairly good modulation, breaking feels slightly spongier than alloy clinchers and requires a larger handful of the leavers to stop within the same distance. On occasion, hard sustained breaking induces a bit of screaming from the rim (maybe I need to toe in the pads more).
I do not have a great deal of experience riding these wheels in the wet. However, I conclude that the best option is to not ride these wheels in inclement weather. Put simply, riding in traffic is not safe. At a guess, it takes around triple the distance to come to a stop as it does in dry weather. As such, emergency breaking is out the window. If you’re racing on a non technical course, then knock yourself out.
All up, these slight sacrifices are not too bad, you just simply need to change your braking habits i.e. hit the brakes earlier.
The good
- Low weight improves handling precision and provides a buoyant sensation to the ride – with a stiff, responsive frame, your bike feels like a rocket ship
- Amazing acceleration out of the saddle
- Low rolling inertia makes for a very good climbing wheelset (though my times up black mountain were faster with Bora’s)
The not so good
- The rim profile is antiquated and noticeably less aero than the competition
- The hubs are inferior and require ongoing maintenance
- Ride quality is wooden and slightly dull
- Extreme vertical rigidity significantly increases harshness
- Unrepairable in the event of a crash
- Price
Rating: 6.5/10
Recommendations
Given the quality of the hubs and the effect they have on the perception of speed as well as the road feel of the ‘un-aero’ v-shaped rims, I cannot recommend these wheels. Put simply the competition are better. If you were a 80kg+ rider, then the stiffness in these rims may be of such value as to override the wheels other limitations. However, for lighter riders, the extreme stiffness makes for a wooden if overly harsh ride quality. Having said that, the sensation of a super light, nimble bike that instantaneously responds to initial input is an addictive sensation. As such, this wheelset is a paradox in that concurrently fantastic and inferior at the same time. Again, wide tubs or a less racy frame might help with the harshness.
Review Limitations
No single review can ever fully articulate how a product will perform for every kind of rider. As such, it is worth noting a few limitations of this review. First, I did not test this wheelset on different framesets. Some wheelsets really compliment a frames ride quality whereas others mask or inhibit them. It’s conceivable that some of my opinions would change had I ridden them on a different frameset. Second, I am a light guy. What induces jarring stiffness for me is possibly perfectly stiff for someone maybe 10-20kg heavier. Third, I have relatively limited experience with tubular wheelsets. Finally, I did not put a huge number of kms on the wheels (~700km).
