Mosaic takes the emerging 32-inch wheel format beyond experimentation with a ground-up titanium platform designed for speed.
32-inch wheels aren’t new, the industry saw the invasion of 32-inch technology hit at Sea Otter this spring. However, until now, the bikes built around the new platform have largely felt like experiments.
Mosaic is ready to change that.
Introducing the Mosaic GT i55 32, a handmade titanium gravel bike designed from the ground up around 32-inch wheels. It’s built with the singular goal of taking the theoretical performance advantage of a larger wheel and turning it into a gravel bike you actually want to ride.
Rather than adapting an existing frame to accommodate oversize wheels, Mosaic approached the GT i55 32 as an entirely new platform. Frame geometry, rear triangle, axle standards, tire clearance, and in-house-designed 32-inch gravel fork were developed together to address the challenges that have kept larger wheels from translating into truly high-performance gravel bikes.
Mosaic GT i55 32 Key Updates
- 32-Inch Wheel Platform: Purpose-built around the efficiency, momentum, and rollover characteristics of a larger-diameter wheel.
- 55mm (2.2-inch) Tire Clearance: Designed around high-volume 32-inch gravel tires for speed, traction, and control over rough terrain.
- Zero Components 32-Inch Gravel Fork: Mosaic-designed 445mm axle-to-crown fork with 60mm offset minimizes front-end height and helps manage toe clearance across frame sizes.
- Compact Rear Geometry: 440-445mm chainstays and offset seat tube tuck the rear wheel beneath the rider to preserve responsive handling.
- 3D-Printed Titanium Yoke: Creates the tire and drivetrain clearance necessary to package the larger wheel within a performance-oriented titanium chassis.
- Standard Gravel Chainline: The 3D-printed yoke and compact rear end allow the GT i55 32 to retain standard gravel drivetrain clearance for up to a 46T chainring.
- Immediately Available with Made to Order: Available through Mosaic’s Made to Order program at launch.
What 32 Inches Changes
Mountain biking went through a similar evolution more than a decade ago. Larger diameter wheels proved their value because they carry momentum efficiently and roll more easily over rough terrain. Now, as gravel racing becomes faster, rougher, and increasingly technical, Mosaic believes this is the best platform to put 32-inch wheel technology to the test.
Compared with a traditional 700c wheel at an equivalent tire width, the 32-inch wheel offers a shallower angle of attack when encountering rocks, washboards, holes, and other road obstacles. The larger wheel can carry momentum more efficiently across uneven surfaces and provide greater stability when the terrain gets rough.
On paper, the advantages are compelling. But making them work on an actual gravel bike is considerably harder. A larger wheel affects nearly every element of bicycle geometry. It can increase stack height and wheelbase, create toe overlap, lengthen chainstays, and ultimately produce a bike that feels more cumbersome than fast.
Mosaic’s answer wasn’t to design a gravel bike that happens to accept 32-inch wheels. It was to design a dedicated 32-inch gravel race bike.
Making a Big Wheel Feel Small
At the heart of the GT i55 32 platform is a completely redesigned titanium chassis intended to tuck the oversized wheels as tightly beneath the riders as possible.
- Chainstays: Mosaic targeted chainstays of 440-445mm, keeping them as short as possible given the wheel diameter to preserve responsive acceleration and handling.
- Seat Tube: An offset seat tube creates additional room for the rear wheel, while allowing Mosaic to shorten the overall wheelbase.
- Bottom Bracket: A 3D-printed titanium yoke derived from the GT i55 700c platform creates the space necessary for 2.2-inch wide 32-inch tire while maintaining a modern gravel drivetrain and appropriate frame stiffness.
- Axle Standards: The bike uses a 148x12mm rear and 110×15 front axle standards, reflecting the structural and clearance demands of the larger wheel platform.
- Gravel Chainline: Purpose-built frame architecture maintains standard gravel chainline with clearance for up to 46T chainring – no mountain bike crank required. While 38-42T chainrings will suit most riders on the 32-inch platform, the added clearance provides gearing flexibility for faster race setups.
Every decision works toward the objective to capture the rollover and efficiency advantages of the 32-inch wheel without sacrificing the quick, responsive character expected from a performance gravel bike.
The Fork That Makes It Possible
Perhaps the biggest challenge wasn’t the frame. It was the fork. Existing fork options forced compromises in axle-to-crown height, offset, tire clearance, or fit. All of which would quickly negate the performance benefits Mosaic was chasing with the larger wheel.
So, Mosaic designed its own fork and launched Zero Components along the way.
The new in-house designed Mosaic Zero Components 32-inch gravel fork was developed specifically around the geometry requirements of the GT i55 32. With a 445mm axle-to-crown length, Mosaic worked to keep the front end as low as possible while still clearing 2.2-inch tires.
A 60mm fork offset allows Mosaic to achieve appropriate steering geometry while creating additional toe clearance, which is an especially important consideration with smaller frame sizes. The fork uses a 110x15mm thru-axle and will be available with internal or semi-internal brake routing.
Big Wheels Aren’t Just for Big Riders
The most obvious criticism of 32-inch wheels is also one of the most legitimate, with concerns over what happens to smaller riders. Larger wheels inherently create challenges as frame sizes decrease. Stack height and toe overlap can quickly make the format impractical.
Mosaic saw that limitation as an engineering problem rather than an unavoidable consequence of the wheel size. The short axle-to-crown fork, 60mm offset, compact rear triangle, and offset seat tube all work together to make the platform accessible across a wider range of rider sizes.
And because the GT i55 32 is available through Mosaic’s custom program, geometry can be tailored specifically to the individual rider rather than forcing the rider to adapt to a predetermined frame. For Mosaic, that is particularly important because a new wheel standard only matters if its benefits aren’t limited to the tallest riders in the field.
Not a Concept Bike
The new GT i55 32 platform wasn’t simply designed to generate conversation around a new wheel size. It’s not a prototype destined to disappear after a trade show. Instead, it represents Mosaic’s commitment to 32-inch wheels as a legitimate performance platform.
The GT i55 32 will make its debut at the MADE bike show in Portland, Oregon, and will be available immediately for order. The 32-inch gravel race bike will initially be available through Mosaic’s Made-to-Order program and will later be added to the Batch Built program.
- GT-1 i55 32 Details
- Head Tube: IS52
- Bottom Bracket: T47
- Fully internal brake routing
- Rider-Specific Custom Geometry
- Choice of Mosaic standard paint layout
- Starting at $8,250
- GT-2 i55 32 Details
- Heat Tube: IS52
- Bottom Bracket: T68
- Semi-integrated brake routing via Cane Creek HCR
- Ride-Specific Custom Geometry
- Titanium Ghost Finish
- Starting at $5,000
Learn more at the Mosaic Cycles Website