You may know Mosaic as a boutique titanium framebuilder, but the Boulder-based company also happens to make really, really sweet steel frames for those who prefer that unmistakable ride of a well-crafted steel bike. Hello, Mosaic RS-1.

So what’s so special about the RS-1? First, the lead-time is six weeks. That’s ridiculously impressive considering each frame comes with rider specific geometry and matching Columbus Spirit HSS steel tubes for a tuned ride.

But the individualization obviously doesn’t stop there. Available in both caliper and disc brake variants, the RS-1 can be painted in your choices from Mosaic layouts and 45 stock colors, all done by their in-house paint shop Spectrum Paint & Powderworks.

In addition, each frame can be tailored for mechanical/ Di2/ EPS/ eTap shifting. Also included is a tapered Chris King DropSet Headset and a braze-one from derailleur mount. There’s even a choice of 68mm english-thread or a PF30 68mm bottom bracket to choose from. The seat post diameter is at a fixed 27.2mm.

In addition, each frame can be tailored for mechanical/ Di2/ EPS/ eTap shifting. Also included is a tapered Chris King DropSet Headset and a braze-on front derailleur mount. There’s even a choice of 68mm english-thread or a PF30 68mm bottom bracket. The seat post diameter is at a fixed 27.2mm.

Other small details worth noting are star-shaped cable port/bottle boss reinforcements and an integrated derailleur hanger. 

For the caliper brake-equipped frames, the RS-1 will be spec’d with QR front and rear, 28mm tire clearance and an ENVE carbon road fork.

Meanwhile, the disc-version, the RS-1d will come with front (142×12) and rear (100×12) thru-axles, flat-mount brakes front and rear, 30mm of tire clearance, and a carbon Columbus Futura Disc fork.

The RS-1/RS1d are available to order today for $6,000 per frameset.