Syncros Capital SL Aero wheels made me faster, on fewer watts

The Syncros Capital SL Aero wheels, with their curious carbon monocoque design, are at the cutting edge of road bike wheel development, a superlight solution for riders prepared to invest heavily in their quest for speed. 

They’re a distant descendant of Syncros’s Silverton mtb wheels, the Scott-owned brand’s first one-piece carbon-fibre wheelset launched back in 2018. Those off-road hoops were ridden to victory by Tom Pidcock at the Tokyo Olympics, and carried Nino Schurter to multiple World Cup victories, so the Capitals come with a fine pedigree. 

Essentially, each wheel – rims, hubs, spokes and all – is constructed as a single unit, a technique Syncros says produces a “one-piece carbon wheel system that is lighter, stronger and more responsive”. We’ll see.

Syncros Capital SL Aero wheels construction 

Syncros’s designers’ priorities began with low weight and inertia, moving on to aerodynamics before concentrating on handling, feel and rolling resistance.

The one-piece construction addresses a few of those priorities, minimising the number of components while making them lighter, stiffer and more aerodynamic. 

To create the single unit, the rim’s carbon fibre is laid up by hand, a latticework of carbon spokes is sandwiched in between and a bearing tube, which carries the DT Swiss hub internals, is bonded into place. The spokes lack nipples, or any kind of adjustability, which is fine because they’re set precisely during manufacture.

During product development, Syncros worked closely with German tyre maker Schwalbe, which created the Pro One Aero to bring out the best performance qualities of these wheels. The Capital SLs are both tubeless and hookless, with 28mm said to be the optimum tyre size for both comfort and aerodynamic efficiency.

Talking of aero, Syncros claims the Capitals wheels are 7% faster than any of the fastest competition: DT Swiss ARC 1100 62mm, Campagnolo Bora Ultra WTO 60 and Zipp’s 454 NSW and 404 Firecrest. Of that collection, the DT Swiss wheels are the lightest at 1,381g – still no match for the 1,290g Syncros. The Capitals are sold as being suitable as a gravel wheel too, able to handle tyres up to 50mm wide, though I’d hesitate to take such an expensive set of hoops onto anything remotely rocky.

These wheels are far from a value offering, coming in at a very pricey £3,830/$4,599.98.

Syncros Capital SL Aero wheels ride quality 

I used the wheels on a Giant Defy Advanced SL0 I was testing, transferring the huge 10-36 cassette from the original 30mm-deep Cadex wheels. 

So, are they faster than the stock wheels on my bike? Yes, without reservation. Every comparable ride on the Syncros wheels was faster than on the stock Cadex wheels. One ride used eight watts less and was 2.4kph faster than another with the stock wheels on a similar route in almost identical conditions. All rides on the Capitals used less power than rides on the stock wheels at comparable speeds. 

On faster rides where the aerodynamics could really make a difference, the power saving was even greater. So, racers travelling at race speeds stand to get the most out of these wheels.

Accelerating out of corners wasn’t quite like opening the throttle on a motorbike, but they spin up so quickly that I couldn’t help but smile. And do it again. And again. Up hills and on the flat, once up to speed it’s easy to stay there – it feels like you’re being sucked along, all the time making a delicious whooshing sound.

It’s not just the noise and speed that make these wheels a delight – the handling is sublime. They slice beautifully through every curve, they’re truly confidence-inspiring, they’re stiff, but not unforgiving, none of that rigidity compromises comfort. And, while the bane of all deep-section wheels used to be crosswind performance, the Capitals maintain stability well. Despite deliberately heading out on windy days, the only time I was caught out was when a lorry passed too close.

Are they faster than the competition? Well, we tested these wheels in real-world conditions, rather than against their rivals in a wind tunnel, so it’s hard to say whether they really are the world’s fastest, as claimed.

Syncros Capital SL Aero wheels value and verdict

The Syncros Capital SL Aero wheels don’t just look great, they’re light, fast and stable. In short, they’re the best-handling wheels I have ever used. If we put the price aside, these unique wheels are exceptional. 

However, for most of us, £3,830/$4,599.98 is a prohibitive amount of money to spend, even when considering the crash replacement scheme that brings peace of mind should the worst happen.

Syncros Capital SL Aero wheels specs 

• Tyre compatibility: Tubeless and hookless 
• Depth: 60mm 
• Internal width: Front 23mm, Rear 25mm 
• Claimed weight: 1,290g 
• Maximum rider weight: 120kg 
• Min tyre width: 28mm 
• Maximum tyre width: 50mm 
• Hubs: DT Swiss 240 custom internals