Wilderness Trail Bikes‘ (WTB) Nano 40 tires have an impressive lineage. The 700×40 Nano‘s tread pattern is based on the company’s long-running Nanoraptor 29er tire. And according to WTB, the full-sized Nano is the number-one tire choice for Tour Divide ultra-marathon event.
The Nano 40C is available in three versions: TCS Light ($54.95 MSRP), Race ($49.95 MSRP), and Comp ($31.95 MSRP). We tested the Race model, which features a folding aramid bead, WTB’s DNA rubber compound, and a lightweight 60 tpi casing. Our sample tires weighed 460-462 grams (less than the 470 gram advertised weight), and measured 40.1 mm when mounted in 22.6 mm-wide rims (18.5 mm inner width).
While the 40 mm Nanos may look a bit anemic when compared to full-sized 29er tires, they have far more volume than your typical ‘cross knobby. The Nano’s casings have a decidedly u-shaped cross-section, which puts of lot of air between you and the ground. That plump profile, combined with a recommended pressure range of 35-65 psi, translates to a smooth, comfortable ride on rocky trails and broken pavement. Unlike some competitors’ tires that utilize excessively large side knobs (which tend to be largely cosmetic), the Nano’s tread is actually narrower than the casing (by approximately 5 mm). That unique combination means more clearance at the frame and fork.
The Nano’s tread pattern features an elevated centerline that rolls efficiently and quietly on hard surfaces, but don’t mistake these for run-of-the-mill hybrid tires. On soft, loose soil, the WTB tires really shined–yet they remained squirm-free when railing turns on hardpack and loose-over-hard. Even though the majority of our testing took placing during dry weather, we were pleasantly surprised at how well the WTB tires performed in light snow. We tested the WTB tires at various pressures, and found that they worked best between 40-55 psi (depending on riders’ weight, terrain, and riding style).
It’s obvious that the Nano 40C can’t–and isn’t designed to–replace dedicated road or mtb tires. That said, on-road performance is quiet and fast enough so that riding (pavement) to the trail isn’t something to be avoided. And once you reach the trailhead, off-road performance is as good as it gets for a tire of this size.
Disclosure: WTB provided review samples for this article, but offered no other form of compensation in exchange for editorial coverage.