Yesterday, we wrote that the supporting ecosystem around 32-inch wheels is beginning to catch up. Today, there’s another fairly significant piece to add to the puzzle: an actual bike you can order.
Mosaic has unveiled the GT i55 32, a handmade titanium gravel bike designed around 32-inch wheels. And the Boulder, Colorado, brand is making its intentions pretty clear: this is, in its words, “not a concept bike.”
Thirty-two-inch wheels are quickly becoming the bike industry’s biggest new trend. We saw a host of bikes, wheels and tyres at Sea Otter, followed by perhaps the highest-profile example yet at Unbound Gravel, where defending champion Cam Jones and ultra-endurance racer Robin Gemperle raced Scott’s RC Gravel 32-inch prototype. But Scott made it clear that its bike was a “pure prototype,” stating that it “will never be released on the market.”
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Mosaic, meanwhile, is going the other way. The GT i55 32 will debut at this weekend’s MADE bike show in Portland, Oregon.
Mosaic isn’t the first brand to move beyond the prototype stage, nor is it the only 32-inch bike headed for consumers. Stinner has already shown its Refugio 32 with pricing attached, BTCHN’ has been preparing its Bandito for production, and Salsa has said 32-inch Fargo framesets will go on sale this summer, with complete bikes to follow later in the year. Mosaic stands out in that its made-to-order platform is available from launch. A Batch Built option will be added later.x
“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,” Mosaic insists. “Instead, it represents Mosaic’s commitment to 32-inch wheels as a legitimate performance platform.”
More than simply squeezing bigger wheels into a gravel bike
(Image credit: Mosaic Cycles)
Larger wheels bring some compelling theoretical advantages. Compared with a 700c wheel running an equivalent-width tyre, the shallower angle of attack should help it roll over rocks, holes and generally rough terrain more easily, while the larger wheel size is also claimed to carry momentum more efficiently.
But there are compromises. Bigger wheels increase stack and wheelbase, stretch chainstays and can create toe-overlap headaches – particularly as frame sizes get smaller. They’re concerns Cycling Weekly has looked at in depth in previous coverage.
“…A new wheel standard only matters if its benefits aren’t limited to the tallest riders in the field,” Mosaic states and tackled the aforementioned limitation as “an engineering problem rather than an unavoidable consequence of the wheel size.”
For starters, the brand’s designers decided to design an entirely new platform from teh groun up rather than modifying one of its existing gravel bikes.
The frame uses a bent seat tube and relatively compact 440-445mm chainstays to tuck the rear wheel beneath the rider. A 3D-printed titanium yoke creates clearance for tyres up to 55mm (2.2″), while still accommodating a standard gravel chainline and chainrings up to 46 teeth.
The axle standards do move into mountain bike territory, with a 148x12mm rear and 110x15mm front.
(Image credit: Mosaic Cycles)
And then there’s the fork
Mosaic says one of its biggest headaches was finding a fork that would allow the geometry it wanted without pushing the front of the bike too high.
So it made its own.
The result is a new 32-inch gravel fork under Mosaic’s new Zero Components name, with a 445mm axle-to-crown measurement and 60mm offset. The former is intended to keep the front end down, while the latter helps Mosaic achieve its desired steering geometry while creating more toe clearance.
Mosaic says the combination of its shorter fork, increased offset, compact rear triangle and offset seat tube helps make the platform work across a wider range of rider sizes.
And because these bikes are being offered through Mosaic’s custom programme, geometry can also be tailored to the individual rider.
You can actually buy this one
(Image credit: Mosaic Cycles)
Mosaic is rolling out the GT-1 i55 32 in two initial versions:
- Fully integrated: The high-end option gets fully internal brake routing, a T47 bottom bracket and a choice of Mosaic’s standard paint layouts, with pricing starting at $8,250.
- Semi-integrated: The second option offers semi-integrated brake routing via Cane Creek HCR, a T68 bottom bracket and Mosaic’s Titanium Ghost finish, and starts at $5,000.
Both come with rider-specific custom geometry.
More information can be found at mosaiccycles.com.
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