Mosaic Custom Steel 29er

Modern Steel Tubeset means Comfort of Steel with Precision Handligng. Hand Made in Boulder, Colo.

Reviewed by Scott Leonard

Weight: 25 lbs (as tested)

Price: $1100 (frame only), $2600 (complete as tested)

Boulder based Mosaic Cycles hand builds custom and a line-up of titanium, steel and stainless steel bikes in their North Boulder shop. Mosaic was established in early 2009 by Dean Titanium Cycles alums, Aaron Barchek and Nick Phillips. Aaron worked at Dean for 6 years and ended his tenure there as a head frame-builder. During that same period he earned a degree from CU in Physiology.

The 29er single-speed Mosaic set me up with is Aaron’s personal bike. Luckily we are similar in stature, so despite not being a custom build it fit well. The job description for this bike is a keep-it-simple workhorse. The True Temper OX Platinum steel tube set is TIG welded. The beads are so fine and consistent that the powder coat erases them giving the joints a fillet brazed look. The rear dropouts are stout Paragon Machine Works units bolted to closed horizontal slot style dropouts brazed to the stays. The slots are long enough to tweak the chainstay length within a good range—making it easy to swap out cogs within a range of 2-3 teeth without adding chainlinks—and the design allows for swapping to dropouts that accommodate a derailleur. The bike’s clean, simple setup and perfect fabrication is highlighted by the British racing green with Mango highlights paint scheme by Spectrum Powderworks.

In line with the keep-it-simple theme, the bike is equipped with a White Brothers carbon legged rigid fork and Avid cable drawn disc brakes. The wheelset combines a Velocity 35mm wide rim with Chris King hubs and Maxxis 2.4-inch Ardent tires. The wide rim’s and high volume tires allowed for compliant tire pressures even with tubes, which added significant comfort to the fully rigid ride.

Laying down perfect beads on premium tube sets is a given in the hand built world. Developing a geometry and layout that makes the bike an extension of the rider and optimizes wheel size, frame material and drive train is what makes exceptional bikes. Mosaic’s design does it well. The head and seat tube angles are quite steep; I felt perched over the pedals and close to the front tire. The bottom bracket is slung fairly low, keeping the center of gravity down; the bike does not feel tall. The overall geometry and layout essentially slots the rider neatly between the tires; the effect is intuitive and predictable handling and the ride is stable and connected. The bike is nimble and tracks like a drone; you literally look at small gaps and terrain features you want to use and ride precisely where you want to go. The rear triangle features compact chain-stays and the frame has significant lateral rigidity in the bottom bracket area: the rear tire stays planted during out of the saddle bursts and all your effort is directed into the contact patch. Weighing 25 lbs—even with the stout rims and tires—helps too.

I rode the bike extensively on the smooth, flowing trails on The Crown south of Carbondale, Colo. and for 3 hours at Phil’s World near Cortez. On fast, smooth, gliding style terrain the bike is exceptional; the cornering grip and precise handling allow you to stay off the brakes and “ski” the terrain. In fast sweepers I was able to rail the fat tires on subtle terrain features like grooves in dried mud. Unfortunately the refined ride was occasionally disrupted by the harsh, modulation-less mechanical disc brakes – a simple and deserved area for an upgrade.

Aaron’s 29r is a sweet ride. The bike leverages the assets of the big wheels, steel tube set and single speed drive train to create a simple machine with a refined and sophisticated ride.

Mosaic has partnered with Full Cycle in Boulder and Fort Collins to be their local dealer. Test ride bikes are at the Pearl Street and Fort Collins locations so prospective customers can check out Aaron and Nick’s work. The knowledgeable sales staff can initiate the custom build process or help select the correct model and size from Mosaic’s stock, hand-built offerings.—S. Leonard

Find more info at Mosaic Cycles or call 303.596.3533 Order one at Salvagetti Bicycle Workshop in Denver, Colo.

Aaron Black and Nick Phillips at Mosaic kept the price of this steel 29er within reason - $110 for the frame - by tig welding the joints but the quality of the welds is fantastic.	Paragon Machine works sets the industry standars in high quality machined frame parts. Mosaic chose these nice Paragon slider dropouts for adjusting the chain tension. Great choice.	The Euro racing green paint by Spectrum Powderwords - another industry Standard Setter - and bright orange components made for a cool, subtle bike with a little flare.
Steel tubesets have come a long way in the last decade and the True Temper OX platinum tubes are surprisingly responsive on climbs (especially with the White Brothers rigid carbon fork).	Steel tubes combined with 35mm wide rims and 2.4 tires helped make the Mosaic ride smooth.	Handling on the decents was stable and reliable - quick - meaning Mosaic got the 29er geometry right.
Reasonably short rear chainstays kept the rear tire connected to the gound when climbing out of the saddle.	Riding the Mosaic 29er in the desert terrain near Fruita, Colo. made me appreciate the big tires.	The rigid fork, as expected, made for responsive handling but after a few hours in the saddle I could feel every drop all the way up to my shoulders.
The spectrum paintjob is top notch.	Mosaic did a great job specing the bike - especially considering it's reasonable $2600 price tag.	Handmade in Boulder, Colo. - Mosaic will build it right.