Campagnolo's new Bora Ultra 35 is an excellent racing wheelset that works well in a variety of conditions. We tested the light-but-aero tubulars on two short rides and then raced them in the 105-mile Campagnolo Gran Fondo New York.
With more than 8,000ft of climbing and pouring rain for the five-hour event, the race proved to be a great trial for the wheels, especially the new diamond-sanded brake tracks and accompanying pads.
At 1,230g for the set, the Bora Ultra 35s handle confidently in crosswind gusts. They also accelerate quickly, handle high-speed potholes without issue, ascend like purpose-built climbing wheels, and brake very well in the wet. And, although we didn't need to adjust them, we appreciate the external spoke nipples for serviceability.
Our Colnago test rig
Braking has long been the Achilles' heel for all-carbon wheels. While no one has disputed that an all-carbon wheel is lighter than a metal one, or even a metal/carbon hybrid, you don't have to dig too hard to find examples of lousy braking on a carbon brake track.
Thankfully, not all carbon brake tracks are created equally. And, with many manufacturers now having a few years of experience working with carbon under their belts, some are putting forth commendable options. The Bora Ultra 35 is one such example.
At the risk of stating the obvious, there are two main elements in carbon wheels: carbon fiber and resin. The carbon fiber itself is a bit tricky for a braking surface because it's so hard and smooth; when completely wet, there's a brief delay on braking engagement on carbon, whatever the brand. The resin is in some ways more complicated, because it changes under the friction and heat braking creates.
The Bora Ultra 35 has a diamond-sanded brake track that works quite well for carbon
Campagnolo's solution to this was to mill off as much of the top resin layer as possible, leaving bare carbon fiber for the braking surface. The company certainly isn't the only one to have done this. Austrian company Xentis, for example, sands off the top layer as well. But Campagnolo claims that its diamond-tipped sanding tool is quite precise and sands off the resin without leaving behind any residue, as some other processes supposedly do.
The end result is safe, smooth, predicable braking. We used Campagnolo Record brake levers, calipers, and red brake pads, along with Continental Competition tires. The combination made for complete confidence bombing down twisty descents in the pouring rain.
Yes, the half-second delay that plagues carbon rims still exists as the brake pad squeegees away water, but braking quickly kicked in - and always with a smooth, linear application. There was never any grabbiness, pulsing, or fading, nor were there any of the obnoxious squealing noises that often come with carbon.
Campagnolo claims it developed and produced the new red brake pad in house. Slowing down from high speed, the brakes sound like a spaceship from a 1980s video game, a steady glissando from a high tone down an octave or two during deceleration.
Braking increases linearly, with more stopping power evenly applied at the wheel with more lever pressure. We never felt as though we had to put a death squeeze on the brakes – which certainly can’t be said for some other carbon brake tracks. For example, riding a bike with SRAM Rival brakes on Lightweight wheels in a rainstorm, we had to pull incredibly hard on the levers coming into sharp turns, and the braking would occasionally surge or grab.
Easy up, fast down
At 530g for the front and 700g for the rear, the Bora Ultra 35 wheels like to go up. For climbing, less weight is always better - to a point. A so-light-it's-flexible wheel is not good. The Bora Ultra is rock solid in terms of stiffness; with the brake pads set about 5mm off the rims, we were unable to get the wheel to rub the pads when out of the saddle. And standing up to accelerate was rewarded with quick spin-up.
Although the rain was the bigger test for the wheels, we did experience some crosswinds and got the wheels more than 50mph/80kph on a long descent. Although the wheels felt faster in these situations than a box-section rim, handling was easy. Flying downhill in fog and pouring rain, we felt as confident as if we were riding our own bike.
We felt completely comfortable descending unfamiliar roads in pouring rain
Quantifying the aero benefit based on a ride is impossible, but in terms of the wind tunnel findings of many companies, it stands to reason that a foil-shaped 35mm tall rim will be faster in most situations than a standard rim.
All told, the Bora Ultra 35 is a great tubular racing wheelset. If you're a Campagnolo rider with an affinity for pinning on numbers, they are definitely worth a look.