Weight: 23.5 Price: $3,300 (frame only) Price: $8,000 (as tested) www.MosaicCycles.com
by Scott Leonard
Twenty-niner hardtails are synonymous with cross-country racing; with low BB heights and steep, quick-handling geometries, they’re designed for speed. The smooth-rolling, confidence-inspiring big wheels and efficient platform that make the 29er hardtail the go-to for racers can also be leveraged to create trail bikes that make you forget about rear suspension.
Aaron Barcheck of Mosaic Cycles in Boulder, Colo., built this beautiful 29er in his own vision of what a 29er should be. It is an excellent example of a hardtail trail bike, built to be fast and lively and fun to ride. The titanium tube set is focused on strength and durability. The frame features a 1.5-inch head tube to accommodate a tapered steerer tube fork and large-diameter tubing throughout. The rear triangle is relatively compact but 17.7-inch chainstays add stability while allowing ample clearance for up to a 2.4-inch tire. These features add up to a seriously stiff, strong frame that seems impervious to abuse. Cable and hose routing follow the top tube to minimize exposure to mud and dust. Handbuilt frames deserve top-tier groups, and this Mosaic 29er features an XTR drive train and brakes, Easton EC90 carbon seatpost, Easton Haven carbon handlebar and NoTubes Crest ZTR rims laced to Chris King hubs with DT Swiss butted spokes and Maxxis Ardent 2.25 tires.
According to Barcheck, the geometry is the result of an evolution over the last few years of 29er builds for riding in Colorado. “I’ve seen a shift from hardtail race bikes, where weight and fast handling have been desired, to more all-around trail-oriented 29ers,” Barcheck notes. The fundamental changes to the geometry are a slackened 69.5-degree head tube angle and higher bottom bracket. The geometry is based on a 100-mm fixed travel fork. However, Barcheck planned for and equipped the bike with a 100- to 120-mm Fox TALAS fork.
In 100-mm mode, the handling resembles an XC bike and climbs exceptionally well. The rear tire hooks up and the front tire stays planted without “hunching” over the bars. The bike shines on loose, rocky climbs that require a mix of on- and off-the-saddle climbing techniques. With the taller BB (12.125 inches), you rarely clip a pedal. The oversize tubeset ensures that every watt gets delivered to the rear contact patch. None of this surprised me.
What did surprise me was the change when the fork was in 120-mm mode: The additional 20 mm of travel, along with the extra slackened head tube angle (20 mm of added fork height roughly equates to a half degree decrease in head tube angle) had a dramatic effect on the handling. I rode the bike down a primitive trail with a lot of hidden obstacles, rough, steep rock/root sections and a very fast groove section: proper all-mountain terrain. The bike rolled easily over unseen obstacles with inspired assurance. Drops and super steep rock gardens were no problem; it felt like there is no way you can go over the front wheel. The stability of the bike at speed is impressive—so impressive I found myself going a bit too fast at times. The bike feels planted and nimble, a combination I attribute to the exceptionally stiff, precise frame that keeps the big wheels tracking and weight distribution optimized. Swapping up to 2.4 tires and adding a dropper seatpost would elevate the all-mountain performance and comfort even more.
My overall impression is that this Mosaic 29er is versatile and bomber. With 120 mm of front travel the bike inspires confidence and can really deal with gnarly terrain. I never missed rear suspension and certainly appreciated the weight savings and climbing ability of the hardtail. Mosaic builds beautifully detailed custom bikes to the rider’s spec, so geometry details are up to you. But if you let Barcheck apply his vision, you’ll end up with a hardtail 29er that is perfect for a rider who savors huge rides off the beaten path and wants a simple, low-maintenance, super tough yet elegant bike.