The snub-nosed ‘U-shaped’ Accelero rim profile was first seen on 3T’s Mercurio full carbon wheelsets, and has trickled down to the Italian company’s more ‘affordable’ offerings. They’re hardly budget wheels, but they are competitive among similar offerings, and an aluminium rim of the same depth would come with a greater weight penalty.
The Acceleros combine the convenience and versatility of clincher tyres with the consistent braking of an aluminium rim and the aero and weight saving benefits of carbon. The carbon is a structural fairing, bonded to the aluminium rim and resulting in impressive rigidity (and noise levels).
Including rim tapes our test pair weigh 1950g, making them less suitable for an Alpine assault, but over flat and rolling roads their mass isn’t so noticeable. Measuring 23mm wide at the braking track, 22.5mm at the mid point, and 63mm deep, they’re usefully wider than the 21mm rim standard but not in the same league as Zipp’s 28mm-wide Firecrest. With a 23mm tyre, air volume is limited and comfort reduced compared with larger tyres; fitting 25mm rubber improves both comfort and grip levels.
With 18 radial spokes and the deep profile, the front wheel is impressively stiff, resisting deflection from sprint efforts and steering incisively. The rear, with 24 spokes, is strong and reactive and its rigidity ensures as much power as possible is transmitted to the tyre. We did find the freehub a bit sluggish to engage, but it’s more a mild annoyance than a performance problem.
These wheels come into their own at speeds over 20mph, when their increased stability becomes more obvious. On deep V-section rims in blustery crosswinds we’d expect to be regularly reacting to sharp, wind-induced flicks from the front wheel, occasionally both, but the 3Ts offer a far more relaxing experience, the only evidence of aggressive winds being a gradual and easily countered pressure nudging us off line. Despite their weight and slow pickup, it’s the rims’ performance that elevates the Acceleros above their V-shaped competitors and, unless you live in the mountains, they’re reliably rapid.