One of our closest frame-building partners is Mosaic Cycles out of Boulder, CO. Founder and head welder Aaron Barcheck is our kind of people: direct, no-nonsense and dedicated to his craft. This zero-fluff mentality translates directly into his frames. Mosaic makes some of the most performance-first titanium and steel bikes in the United States. Sure, they can be beautifully painted and intricately designed by their paint shop, but at the end of the day, Mosaic is all about delivering a phenomenal ride without a bunch of extra marketing flare. And they deliver that in spades.
Mosaic makes road, gravel and even hardtail mountain bikes in predominantly titanium but also offers a couple of models in steel. Here's an easy way to decipher Mosaic's model names:
R = Road
G = Gravel
M = Mountain bike
T = Titanium
S = Steel
1 = Custom butted tubing, custom paint and custom geometry
2 = Straight gauge tubing, stock geometry and a raw finish*
AR = All road frames able to handle up to 700x38 tires
45 = A gravel frame able to handle up to 700x45 tires
X = A gravel frame able to handle up to 29" x2.25" (700x50ish) tires
(And to help confuse you more, there is an XT-1 that can only clear a 700x38, but I'll explain more about that below)
Hence: "GT-1 AR" is a titanium all-road bike with custom butted tubing, custom geometry and a single custom color optimized for 700x38 tires.
Clear as mud? Similarly, it can be a bit difficult to understand which riders Mosaic has in mind for each of their various frame models, so here is our breakdown of the Mosaic line-up.
The Mosaic RT-1/RT-2
Light, efficient, durable, comfortable and hella fun, the RT series was designed for the weekend warrior as much as for the racer folks. It is rare to have a bike that can cater to such a wide variety of roadies. Yet, due to Mosaic's custom build process and oversized titanium tubing, the team in Colorado can create a road bike for almost any rider with metal dreams. The RTs are available in either rim (clearance for 700x28 tires) or disc brake (clearance for 700x30 tires).
The Mosaic RS-1
If you don't mind the extra weight and love the feel of steel, the RS-1 could be your perfect riding companion. It's designed for a fun and sporty ride like the RT, but the RS-1 offers oversized custom-butted Columbus Spirit HSS tubing to make their bikes ride like a modern performance road bike should. The RS-1 is available in rim (clearance for 700x28 tires) or disc brake (clearance for 700x30 tires).
The Mosaic GT-1 AR/GT-2 AR
All-road riding is a strange category that says yes to the sort of iffy surfaces that cause the average road bike to think twice. With clearance for 700x38 tires and exclusively built for discs, the AR range strips away your inclement weather riding excuses, allowing you to hit your local fire road if the spirit moves you. A super versatile road bike? A racer's gravel bike? The AR is all that and more.
The Mosaic GT-1 45/GT-2 45
The gravel rider's weapon of choice. Space for up to 700x45 tires and the option of extra mounts on the fork for fenders and racks make the 45 an all-terrain fun machine. The GT-1 45 is one of our best-selling bikes at AC due to its lively yet damped ride, generous tire clearance and stable handling. For those who want a titanium gravel bike ASAP, the GT-2 45 is part of Mosaic's Batch Built program and can be delivered in stock sizes within 3-4 weeks (optional paint and finish extras can add on some time). The 45 series is disc brake only.
The Mosaic GT-1 X/GT-2 X
Are your local trails more on the "brutal" end of the spectrum? Maybe you want to run massive tires on your drop bar bike. Or perhaps you want a flat bar bike camping bike? The X has got your back. Able to clear laughably wide 29x2.25" tires, you can take your X to trails where other gravel bikes might fear to tread. The X series is "gravel drivetrain" specific due to its wide tire clearance. Need to know what that means? Just email us, and we'll explain. The X series is disc brake only.
The Mosaic XT-1
If you have a tire measuring block in your garage to ensure your 700x33 tires are UCI-legal, this is your Mosaic. The XT-1 is Mosaic's cyclocross race bike. Light, efficient and with just enough compliance to make race day a little brighter. Enve's CX fork helps keep the front end in check, and the bike's flat mount disc brakes will let you slow you down before you slam into the barriers (or spectators). The XT-1 can clear up to 700x38 tires.
The Mosaic MT-2
XC, down country or just a hardtail mountain bike, call the MT-2 what you want but know that it will do just a bit more than you'd expect it to. Built around a 120mm stroke front fork using light and strong, oversized titanium tubing, the MT-2 is ready to party on your local singletrack. We have built up a couple here at AC now, and even the mid-weight builds came in around the 25-pound mark (and that was with rim inserts, dropper post and overbuilt suspension). This is the new benchmark for hardtail mountain bikes.
*The 2 series frames can be upgraded with any of Mosaic's various options, but they are all offered a la carte on the 2's as opposed to included in the 1 series frames.