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, minimalism and excess—where most real-world riding actually happens. For us, the answer was the GT-1 iAR, Mosaic Cycles’s take on a custom, titanium, multi-surface platform built without compromise.
As one of our most requested builders, Mosaic has earned its reputation through meticulous craftsmanship, thoughtful design, and modern functionality. That philosophy is fully realized in the GT-1 iAR, pairing an ENVE In-Route integrated cockpit and fork with a double-butted titanium frame custom-fit to the rider. The frame retains the unmistakable ride quality titanium is known for, while embracing the integration expected of modern bikes. With clearance for tires up to 40mm, the GT-1 iAR is ready to adapt as terrain, seasons and riding goals evolve.
Up front, we leaned fully into ENVE to keep the cockpit clean and purposeful. The integrated setup reinforces the bike’s road-forward appearance, while the custom-painted stem adds a subtle layer of intention. It’s a small detail, but one that brings the entire build together.
For a bike designed to do a little bit of everything, comfort matters. The Form Throne saddle was a natural choice. Designed and built here in the Bay Area, Form’s saddles are shaped by decades of bike fitting expertise, a trait that becomes evident the longer you ride them. An ENVE seatpost keeps things streamlined, while the AC x Bjorn Skrepka titanium seat collar adds an understated touch.
One of the standout elements of this build in its current iteration is the ENVE SES 4.5 wheelset. Visually, it reinforces the bike’s road-oriented disguise…deep, fast, and undeniably aero. It’s a wheelset with proven pedigree, ridden at the highest levels and a popular choice among clients. To account for the realities of winter riding around Marin, we paired them with Continental Grand Prix 5000 AS TR tires, striking a balance between speed, grip, and confidence across wet and dry conditions.
The off-road intent reveals itself most clearly in the drivetrain. The SRAM Force XPLR 1x13 groupset embraces a “less is more” philosophy, reducing complexity while expanding capability. The wide-range gearing keeps things efficient on smooth pavement, yet fully prepared when the road degrades or disappears altogether. Fewer decisions, more riding.
In its current form, this GT-1 iAR sits comfortably in disguise. Aero wheels, road posture, and a restrained finish suggest speed first, but beneath that surface is a platform built for adaptability. Wider tires, different wheels, rougher roads, changing seasons…it’s all on the table. Subtle at first glance, deeply capable once you live with it and exactly how a do-it-all bike should be.
If you’re looking for a bike before the nice weather hits, Mosaic is a great option with their 2-month build time. It's that time of year—drop us a line and let's get the conversation started.
- Chad
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