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Mosaic
Custom Mosaic GT-1 i55 Titanium Gravel Bike
Custom, handbuilt frames were the original "gravel" bikes, built around bigger tire clearance but with road-going geometry. The Mosaic GT-1 i55 is the natural successor to these original all-surface machines.
Builds starting from $8,250
Enquire about this bike Start with a stock frameCan’t come to California?We can bring the build to you. Wherever you ride, we’ll work with you to create and finally crate up your new dream bike and deliver it to your door.
Gravel Race · 29x2.2
The GT-1 i55 replaces the i45 as Mosaic's gravel race platform, and it's a different frame, not a refresh. The rear triangle is new: a curved seat tube paired with a 3D-printed titanium chainstay yoke, built around Mosaic's own Zero Components Integrated Gravel Fork. None of it is bolted onto the old platform. It's designed as one system, which is how Mosaic gets to 29x2.2 clearance on a 1x-only drivetrain running up to a 48T chainring.
The tubeset is custom 3A/2.5V double-butted titanium, built rider-specific the way every Mosaic is. What's changed is what surrounds it: an IS52/52 tapered head tube, T47x68mm bottom bracket, UDH dropouts at flat mount, and fully integrated routing that requires a gravel-wide chainline.
Winter bike? Gravel racer? Bikepacking? With Mosaic, the possibilities are indeed endless, with a litany of frame options, from fender/rack mounts, pump pegs, and bespoke paintwork. Every Mosaic GT-1 that leaves Above Category is custom-built for the individual, with geometry and tubeset choice based on your answers to our questions about your riding style, current bike setup, riding/racing aspirations, and biomechanical dimensions.
Ordering process
Whether you’re already set on a certain make and model of frame, or still have some questions about how to go about your build, drop us a line and we can talk through your options. From the first detail to the final finish, we'll help you dial in the perfect set up for your next dream bike.
Enquire about this bike
Tell us a little about how and where you ride and we will come back to you, usually within a working day.
The AC Journal
From the Journal
Mosaic
BOTW: Mosaic GT-1 iAR Double-take
This week’s BOTW may justify a double take. At first glance, this Mosaic GT-1 iAR dressed with ENVE SES 4.5 wheels reads as a pure road machine. A familiar silhouette, aero intent, restrained finish. Look closer, however, and the story begins to shift. This client wanted a bike that lives in the margins—between fast and functional, road and gravel, minima...
Mosaic
BOTW: Brennan's Back-to-Business Mosaic GT-1 AR
This edition of Bike of the Week isn't just about a new set of wheels we're rolling out of the door to a happy client. It's also the day AC's gravel pro Brennan Wertz unveils his new rig for his hotly anticipated assault on the 2023 off-road race season. And this year, changes are afoot. After riding for Pinarello in 2022, Brennan is returning to the bike...
Mosaic
The Do-Everything Mosaic GT-1 iAR
This week's BOTW is an especially fun one for me. I absolutely love my Mosaic GT-1 iAR fancy pants rain bike and a friend of ours was looking to do something similar with a bit more versatility in mind. Read on to learn about the inspiration and intention behind this eye catching build. First, a little background on my bike and why we came up with thi...
