The Mach 429 Trail is Pivot's efficiency minded cross-country / trail offering. As a 29er, it's a straightlaced and focused machine that speeds through uphill miles pretty painlessly. In this guise, the bike is a proficient descender, with precise steering and a surprisingly hearty suspension feel for a 116mm travel bike. Unsurprisingly, its pleasantly light and nimble nature gets tossed around in the rougher sections. It's much better on smoother downhills where the bike takes its fun very seriously. Despite the trail nomenclature, we found the 29er Mach 429 Trail a bit overwhelmed by a number of our mountain town trails. Our testers also had a hard time getting back behind the saddle, a fit issue. If you stay off the intense descents, the Mach 429 Trail is a solid performer in a racey, cross country kinda way. Springing for knobbier tires and wider rims, or going with the 27.5+ version, goes a long way to expand its range. Its efficiency gains a stability and a sense of humor when you slap on 27.5+ wheels.
We'd take the Mach 429 Trail for 30 miles on an aggressive xc trail. If you mostly ride flowy trails with a minimum of techy / big-hit descents and want to be able to hang with the xc crowd, this bike is a great pick. The 110mm Santa Cruz Tallboy 29er is a more comfortable climber however, and a livelier and more confident descender than the Mach 429 Trail. Both bikes accept 29 or 27.5+ tires.