FiftyOne Bikes Assassin with SRAM Rival eTap AXS: Unboxing & Features

fiftyone bikes assassin review

“FiftyOne Bikes was founded in 2016 by former international rider Aidan Duff, in response to the disappearance from top-end race bikes of the custom options that he had always enjoyed during his career.” –

fifty one bikes assassin review

Behind the FiftyOne Name

“Cycling is a unique sport, one in which it’s teams that compete, but individuals who win and lose. Every team has its designated leader, and the only way for the team to win is for every other member to sacrifice himself in the service of the one. So, when the team members receive their dossards (race numbers), the leaders always carries a number ending in ‘1’ – ‘11’, ’21, ‘31’ – a subtle sign to make them stand out from their team-mates. First, but not among equals.”

fiftyone bikes assassin review

Assassin Gravel Bike with adjustable Geometry for “Massive Capability”

“The Assassin is a progressive gravel bike with a massive breadth of capability and compatibility. Its adjustable geometry is the key to your personal confidence. Rider preferences on bike handling vary and gravel trails vary even more, so one size does not fit all. The solution is our usage-tailored handling, giving you confidence whether you want to race, explore, tour or shred. This is how we use our custom-building experience of creating bespoke geometry to make a better factory bike.”

fiftyone bikes assassin review

“The Assassin is designed around a long toptube/short stem concept, similar to that of modern mountain bikes and in keeping with its progressive, slacker geometry. Reach to the handlebar is maintained while the front centre (BB to front axle) and wheelbase is extended. This increases stability and confidence, especially on rougher descents, and eliminates toe overlap in all sizes.”

Assassin Unboxing & Features Video

In this video, JOM of the Gravel Cyclist crew unboxes the FiftyOne Bikes Assassin, and provides a quick rundown of the bike’s standout features. Be sure to follow the Gravel Cyclist Instagram account and like the Gravel Cyclist page, as teaser images leading up to the review are frequently posted!

fiftyone bikes assassin review

Continued from Above:

“We knew exactly how we wanted the Assassin to ride and our experience and expertise in custom building meant we also knew how to achieve that. The Assassin is made with Toray T1100, 800 and 700 fibres, each deployed according to their relative attributes, resulting in a tough gravel frame that weighs just 1050g (size M), rewards your efforts like a great road bike and provides the comfort you want when the ride is measured in days not hours.”

fiftyone bikes assassin review
Kitted out with SRAM Rival eTap AXS

Compatibility & Options

The Assassin gives total freedom of choice to build your bike to suit your riding and terrain”:

  • 47mm tyre clearance in both 700c and 650b
  • 1x or 2x, up to 50/34
  • Two front and three rear axle positions
  • Dropper post and Di2 jointly compatible
  • Front dynamo internal routing
  • Fender and rack mounts, front and rear
  • 4 portal bosses + 2 bottles
  • Mild, Wild, or custom paint

fifty one bikes assassin review

Who is it for?

Everyone: explorers, shredders, racers, bikepackers and anyone else who loves getting away into the countryside. The Assassin’s adjustable geometry and category-leading compatibility maximise performance in every situation, allowing one bike to do the job of several, without compromise.”

fiftyone bikes assassin review
Discreet Rack Mounts

Why did we make it?

Because we love gravel riding and because we felt that we could use our vast experience of building custom bikes with individually-tailored geometry to bring something new and better to the gravel sector. We understand that the geometry required to deliver a feeling of confidence varies from one individual to the next and we saw a way to deliver that using flip chips that we felt had so far been missed.”

fifty one bikes assassin review
Flip Chip Fork with two positions

Flip Chips Explained

At the rear, two chips offer three axle positions, adjusting the effective chainstay length and overall wheelbase in 5mm increments. Go shorter for more agility, go longer for extra stability, or take the middle option if you want a balance of each.”

fifty one bikes assassin review
Three positions for the Rear Flip Chip

“At the front, the chips offer two positions, High and Low. The ‘Low’ position gives a longer trail and slacker head tube angle, suited to more aggressive riding on more challenging terrain; the ‘High’ position creates shorter trail and a steeper head angle, ideal for gravel races or rides on back roads and less rough terrain.”

  • Long and Low = rugged terrain, more MTB feel, likely on wider tyres
  • Short and High = milder gravel, more road bike feel, likely on narrower tyres
  • Experiment to find the combination that suits you and your riding best

fiftyone bikes assassin review

“Whereas some bikes seek to maintain a constant trail figure when switching from 700c to 650b wheels, that’s the exact opposite to our goal. The Assassin’s flip chips allow you to tailor the geometry and handling to how and where you ride. Having refined the geometry options so carefully, we then ensured that the crucial trail figures remain consistent across all frame sizes.”

fiftyone bikes assassin review

Paint Options

The Assassin launches with two paint options: British Racing Green and Rothmans Racing Blue.”

fiftyone bikes assassin review
FiftyOne Assassin in Rothmans Racing Blue

“Additionally, for an extra cost, customers can choose a bespoke paint design. As a custom builder, our highly creative, original, and beautifully finished paint schemes have always helped our bikes to stand out from the crowds and to allow our customers to feel that they are riding something truly personal and unique. That’s an experience that we want to share with gravel riders, too.”

fifty one bikes assassin review

Carrying Capacities

The Assassin has two bottle cage mounts, plus four extra portal mounts on the toptube, downtube and fork legs, and rack mounts, too. 

  • Rear rack – 15kg
  • Front rack – 5kg
  • Fork leg mounts – 5kg each
fiftyone bikes assassin review
Internal Dynamo Hub support as well

Origins of the name Assassin

“In 1910 the Tour de France tackled the high mountains for the first time, with not one but four high passes in the Pyrenees, including the mighty Col du Tourmalet, in a single stage of over 320km and 6000m. At that time, every road was gravel and those in the mountains were especially rough.”

fiftyone bikes assassin review
Loaded up for the 2021 King’s Road Coast to Coast

“Summiting the fourth climb, the Col d’Aubisque, the leading rider, and eventual stage and race winner, Octave Lapize, was furious at the stage’s excesses and screamed at the race’s deputy director, Alphonse Steinès, “Vous êtes des assassins! Oui, des assassins!” (You are assassins! Yes, assassins!)”

fifty one bikes assassin review

“Our gravel bike concurs with Steinès that riding mountains on gravel is, in fact, a fantastic idea and is happy to accept the name given by Lapize – Assassin.”

fifty one bikes assassin review

FiftyOne Bikes Founder – Aidan Duff

“The Assassin is exactly the bike we had planned and it has totally reignited my love for cycling. Flip chips are well established in mountain biking to provide adjustable handling characteristics. We wanted to bring that idea to gravel bikes because years of building custom road bikes have taught us that confidence is very personal, so there is no single answer to ideal geometry.”

fifty one bikes assassin review

“What’s more, gravel riding varies hugely compared to the road – having the clearance to shove in some big tyres isn’t enough if you don’t tune the ride to suit.”

fiftyone bikes assassin review

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