Tested: ZR Cycles 650B Hardtail Frame

ZR CYCLES 650B HARDTAIL FRAME: $1,650 ($5,200 AS SHOWN)

I had long entertained the notion of buying a 29er hardtail, but at 5-foot-6, whenever I threw a leg over one I felt like I was borrowing my big brother’s bike. Since 29-inch wheels were too big, frame-builder Zack Rielley suggested I split the difference. The 650b wheel size offers most of the attributes of a 29er (traction, momentum, stability) but can be built into a stronger wheel with a lower stand-over height.

The 650b wheel size (midway between 26- and 29-inch wheels) has been around a long time and is popular with Europe’s touring crowd. The story goes that if the Russian military had not bought all of the rugged Nokian Hakkapeleliitta tires in the mid 80s, North American mountain bikers might already be riding these ’tweener wheels.

ZR is one of a handful of builders making 650b frames, but it has been the proselytizing of framebuilder Kirk Pacenti that has really fueled the movement. He got Panaracer to produce a 650b tire called the Pacenti NeoMoto, and Kenda appears to have committed to a 650b version of its popular Nevegal tread.

The brazed steel frame (using Pacenti Heavy Mettle and Columbus Zona tubes) uses fairly standard 71/73 angles, but the details are one of a kind— including a handcut heart on the BB shell, a custom-lugged headtube junction, a seatpost binder built into the toptube and Paragon dropouts that remind me of my old SE Looptail.

ZR brazed my frame around 2.3-inch Pacenti Baby Bear tires, so tire clearance will probably never be an issue. For the build kit, I went with Shimano XTR components, Velocity Blunt rims, DT Swiss 240 hubs, Avid BB7s and a Hope headset and stem. I used a Reba 29er fork, which, combined with a 650b wheel, makes for a trail figure very similar to a standard 26-inch bike.

I was able to squeeze a couple of rides in before racing the bike in the Ore To Shore, a 48-mile point-to-point slog through Michigan’s Upper Peninsula. The 2.3 tires handled the deep sand handily, and the big wheels rolled as well as I could have hoped. In the twisty singletrack, the front end had a bit more flop than I was used to, but flipping the stem gave it a snappy, stable feel.

Bottom line: Fit and ride quality are superb, and even with a burly wheelset, the bike tracks well, especially in loose conditions. I’m looking forward to shodding it with narrower tires when they become available, a move that will be welcome on all-day hammerfests. Is 650b the silver bullet? Probably not. Does it open the big-wheeled world to us vertically challenged? You bet. —DAN POWELL

HIGHS: Fully custom; fits like a glove; lots of details to love; big wheels keep on turnin’

LOWS: Lack of tire and fork choices; odd seatpost size; 650b wheels might not be for everyone

MORE INFO: 847-212-8347; ZRCYCLES.COM