Road bike review: FiftyOne Sika
A sleek, fast bike with a fit that works for all riders

I didn’t want to say the word “endurance” when I spoke with FiftyOne bikes founder Aidan Duff. I had heard he wasn’t a fan of the term when applied to road bikes. Thankfully, he said it first. “We were so reluctant to use the term endurance because I just think it’s very unfortunate that the term has been somewhat tainted by the first generation of bikes in that category, which were very disappointing.”
I agree with Duff. The endurance bikes I reviewed 10 years ago did not feel as peppy as race bikes. But more recently, this past year especially after riding the latest Cervélo Caledonia and Giant Defy, I hadn’t thought, geez, I wish these bikes felt more reactive or that they would allow me to get into positions that feel strong and efficient.

Duff’s “race bike for real people,” as he put it when contrasting what works for the pros and what’s better for the rest of us, is the Sika. It debuted in April 2024, becoming the company’s second made-in-Asia production bike. Duff described himself as a third-generation bike guy. After he raced on the road, he worked with various bike brands before starting his own. In 2016, the Dublin-based FiftyOne started making custom carbon frames. First, the bikes were made with Enve tubes and later with ones fabricated near Cork, about two hours away from FiftyOne’s headquarters.
The custom work that Duff and his group of roughly seven employees had done led to a few features of the Sika. “We found that many customers need a higher head tube,” Duff said. “For the vast majority of people, the front end on a lot of bikes is too low. You might find riders complaining about neck pain or lower back pain. Or, when you get them on the bike, you’re seeing that their arms are fully extended to the point that there’s no bend in the elbow. So guess what? They also complain of speed wobble because their natural suspension at their arms is locked out. They’re bent over and they’re not really able to leverage the strength in their core. So, if you can sit them up maybe an additional 2″, you can really activate that core and the lower back and get additional power out.”

Further, if you need too many spacers beneath the stem, you won’t get the best performance out of the bike. The closer you can get the stem to the head tube, with the fewest amount of plastic spacers, the sharper the handling will be. I opted for 15 mm of spacer stack to err on the side of comfort. I made the right choice.
Another part of the Sika that was influenced by FiftyOne’s custom builds is the longer chainstay length and, by extension, wheelbase. On my size medium bike, the stays are 420 mm, and the wheelbase is 1,015 mm. Compared with the latest Caledonia in size 54, the Sika’s chainstays are 5-mm longer, while the wheelbase is 18 mm longer. Yet, the FiftyOne bike felt a smidge more reactive than the Cervélo. The Cervélo had 30c Vittoria Corsa N.ext tires that measured closer to 33-mm wide on Reserve wheels. The Continental Grand Prix 50000 S tires on the Sika’s Shimano wheels measured almost exactly 32 mm.
While FiftyOne is an Irish company, the Sika does have a Canadian connection. Toronto’s Kevin Quan Studios helped with the industrial design work. Duff said you can see the designers’ influence on the long seatstays with their bends just before they connect to the seat tube. The stays act independently of one another to dampen as much of the road vibrations sent through the frame as possible. On any of the long rides I took the Sika on, a lack of comfort was never an issue. The frame, along with the 32-mm tires, kept everything smooth. If I wanted more tire volume and traction, I could have put on treads as wide as 40 mm.

The bike has a few other features that Duff calls mere common sense. The seatpost has a standard round diameter of 27.2 mm. The bottom bracket is the essentially creak-proof T47. Duff said that his company was one of the first to adopt that style of BB not too long after it was introduced in 2015. The bike uses SRAM’s universal derailleur hanger standard because, as Duff said, “We don’t need to be wasting the world’s energy and resources to forge a new dropout that nobody wants.”
The one-piece bar and stem, however, struck me at first as a slight departure from the common-sense features. But the component actually doesn’t put any outsized demands on the rider. It lets the brake cables run internally. The default bar/stem for the medium is 420 mm at the hoods, 460 mm at the hooks and has a stem length of 100 mm. There are 19 other variants so you can find the component that works best for you. You can’t move spacers from beneath the stem and place them just above to adjust your fit. If you really want to make changes, you’ll have to place some round spacers on top of the stem, creating a doughnut holder at the stem cap. You also have the option to put on a standard bar/stem combo.

One thing Duff pointed out about the bars was the three degrees of backsweep they have at the tops, so your hands rest in a more natural and comfortable position. I actually hadn’t noticed. “You’re probably smashing it in the drops. You should do a nice relaxing ride on the tops,” Duff teased. I might add, the bike’s geometry made it easy to stay aero in those drops, so, why not?
The Sika reminded me of another all-road bike I tested a little more than a year before. It’s one made right around the corner from where I live in Toronto: the Bridge Bike Works Surveyor. It, too, is an all-road machine. (See, I didn’t say endurance.) It sports many of the same features as the Sika. While the Surveyor didn’t spring from a custom-build outfit, its designer, Mike Yakubowicz, has years of bike fit experience and of helping people choose custom solutions. I find it striking that both Yakubowicz and Duff’s team came to many of the same conclusions about what makes the best all-around modern road bike. (Also, Yakubowicz’s Blacksmith Cycle brings FiftyOne bikes to Canada. FiftyOne ships directly to consumers across Canada, too.)
The Sika was an absolute pleasure to ride, not only on my flat local roads, but also on hills in Gatineau Park near Ottawa. The light bike (7.41 kg for the complete build) carried me up hills quickly and efficiently, and descended effortlessly, even helping me to dodge an oblivious deer that wandered into my path. My rides were road-focused, but with the right tires, the Sika would be capable on gravel and even with light bikepacking duties. It’s a fast, comfortable bike for long, fun rides.
FiftyOne Sika
Components Shimano Ultegra drivetrain with 52/36-tooth crankset and 11–30 tooth cassette, Sika one-piece handlebar/stem, T47 bottom bracket, universal derailleur hanger, Fizik Tempo Aliante R3 saddle
Wheels Shimano Ultegra C36 with 32c Continental Grand Prix 50000 S
Sizes SX, S, M, L, XL, XXL
Price $11,000
Website fiftyonebikes.com



