Roval has announced two new gravel wheelsets, the Terra Aero CLX and the Terra CLX III.
Said to be its most aerodynamic and lightest gravel wheels to date (respectively), Roval claims both wheelsets also help tyres resist punctures better than anything it has made before, thanks to their extra-wide FlatStop bead hooks.
The Terra Aero CLX rims use a new 'Chopped Aero Speed Shape' that sees the trailing edge of the rim squared off abruptly. This shape, Specialized says, gives the rims the aerodynamic performance of a 70mm-deep rim, but at a lighter and more manageable rim height of 50mm.
Both wheelsets feature wide internal and external rims, optimised for tyres between 35 and 60mm wide, and use bladed carbon spokes to reduce weight and improve aero performance.
Chopped Aero Speed Shape
The most striking thing about Specialized’s new aero gravel wheelset is the rim shape, which it calls the ‘Chopped Aero Speed Shape’.
While most aero-optimised carbon wheelsets used V- or U-shaped rims, the Terra Aero CLX rims look as if someone has chopped off the lower edge of the rim.
It is, Roval says, a gravel-specific rim shape, rather than a road-specific rim shape scaled up for wider gravel tyres.
Roval claims this enables the rims to perform like a 'virtual 70mm' rim, in terms of aerodynamic efficiency, while keeping the rim height at 50mm for improved weight and handling.
Similar to Roval’s Rapide CLX III road wheels, the Terra Aero CLX wheels feature a slightly shallower, 45mm-deep rear rim to save weight.
As we’ve come to expect of ‘aero’ gravel wheels, Specialized has opted for a greater external rim width of 38.5mm and internal width of 27mm, to optimise for the increasingly wide tyres gravel racers are now using.
Although very wide compared to road bike wheelsets, these aren’t the most extreme dimensions we’ve seen for an aero gravel wheelset. Zipp’s 303 XPLR wheels have 54mm-deep rims that measure 32 and 40mm wide, internally and externally (alongside hookless rims), for example.
In any case, Specialized claims the Terra Aero CLX wheels offer a 5.84-watt advantage over the 30mm-deep Terra CLX II wheels, when paired with its 45mm Tracer TLR tyres.
As with all Roval wheelsets, the rims are hooked and Specialized uses ultra-wide, 5.38mm ‘FlatStop’ beads, which are claimed to reduce the likelihood of pinch flats. The idea is that the energy of a tyre being squashed against the rim is dissipated over a larger surface area, rather than being concentrated on a small point (which could cause a puncture).
The Terra Aero CLX rims are claimed to require 91 per cent more energy than the Terra CLX II wheels to cause a puncture.
Built with aero-optimised carbon spokes, the Terra Aero CLX wheels have a claimed weight of 1,340g (with tubeless valves and tape).
They cost £1,299 / €1,499 for a front wheel and £1,699 / €1,999 for a rear, totalling £2,998 / €3,458 for the set.
Roval’s lightest gravel wheels
In contrast to the Terra Aero CLX, the Roval Terra CLX III wheels focus on low weight and compliance.
At a claimed weight of only 1,079g with tubeless valves and tape, Roval says they are the lightest gravel wheels in their class, and deliver a “21.52 per cent improvement in lateral compliance”, compared to the Terrra CLX IIs.
Like the Aero rims, the Terra CLX III rims use a wide shape optimised for 35 to 60mm-wide tyres, with a 38mm external and 27mm internal width.
The rims also use Specialized’s FlatStop bead hooks, albeit with a slightly narrower width of 4.9mm.
Although the low weight is likely to garner much of the attention here, Roval sees the compliance changes as more significant in improving rider performance.
This is because, the brand says, the improved compliance can significantly reduce rider fatigue over long distances, and help riders to maintain control of their bikes over rough surfaces.
The Terra CLX III wheels cost £1,149 / €1,299 for the front wheel and £1,599 / €1,899 for the rear, or £2,748 / €3,198 for the set.
What next for Specialized gravel bikes?
The launch of a full-fat aero gravel wheelset suggests Specialized (Roval's parent brand) may have had a change of heart about what translates into improved performance on gravel – at least for elite racers.
Specialized's current gravel race bike, the S-Works Crux, launched in 2022 and focused exclusively on keeping weight to a minimum.
Gravel racing has evolved rapidly in the years since, however, with average speeds increasing and an interest in aero-optimisations following suit.
Zipp already has its radically wide 303 XPLR wheels, while we've seen dedicated aero gravel bikes such as the Factor Ostro Gravel, Ridley Kanzo Fast, Wilier Rave SLR and the 3T Racemax2.
With the noted off-road optimiser, Keegan Swenson, having joined the Specialized Off-Road team this season, could an updated, aero-optimised Crux be in the works to support him and the rest of the team?
Pictures posted on Instagram by Swenson show him at Specialized's in-house wind tunnel, optimising his setup on the existing Crux, so it certainly seems the American brand is paying closer attention to how aerodynamic drag impacts performance in gravel racing.
As always, we'll keep our eyes peeled for any developments.
