First Look: Diamondback Mason FS Pro 29

This aluminum longer-travel 29er is just more proof that big-wheeled trail bikes are here to stay.


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One of my favorite New Mexico rides is a lunar landscape northeast of Albuquerque called White Mesa. The trail is mostly roller coaster, flow-style singletrack that’s stained white thanks to the gypsum in the soil. But there’s a craggy ridgeline in the middle of the ride that’s totally out of character from the rest, with a pair of rocky step-downs like a dragon’s spine, including a five-foot ledge. I’d long been told the feature would roll but never worked up the courage or the vision to try it.

Then came the Mason FS Pro—a 140mm aluminum 29er that’s made for slamming descents. I’ve mastered that move every time I’ve taken the bike out to try it. I’ve also ridden this bike on some of the rockiest, techiest descents anywhere, things that normally entail plenty of hike-a-bike—such as the Bugs-Molino-Milagrosa drop on Mt. Lemmon—and the Mason FS made quick work of those obstacles, too. This bike is an excellent rock-crawler that skitters through tough trail like a mountain goat and hands out confidence like lottery winnings.

A couple of years ago, the sense in the industry was that while 29ers were great for XC bikes and hard tails, they weren’t well suited to bigger travel platforms. I actually had one major bike manufacturer tell me that because of the limitations of pairing the large circumference wheels with slacker geometry, it was impossible to make a 29er with more than 120mm (that’s five inches) of squish.

So much for that theory. Bike companies, including Diamondback, have sorted out geometries to easily integrate big travel with big wheels. Now there’s half a dozen excellent long-travel 29ers, including the ground-breaking BMC Trailfox TF01 and the Niner WFO 9, both at 150mm, as well as the Specialized Enduro with 160mm. And 140mm 29ers are commonplace.

This bike is an excellent rock-crawler that skitters through tough trail like a mountain goat and hands out confidence like lottery winnings.

What these bikes, the Mason FS included, offer is not just six or more inches of suspension, but also slacker head angles and lower bottom brackets for more confident descending. The 66.5-degree head angle mated to 60mm stem on our size medium tester makes for one of the most confident descending bikes we’ve been on this year, especially with the Crank Brothers Kronolog seat post dropped.

The full aluminum construction and the (okay, we have to say it, awkward looking) Knuckle Box linkage mean the Mason FS isn’t exactly light—30.6 pounds to be exact. But in some ways we like the extra heft. No, it doesn’t make for the most chipper climbing, though most testers agreed it went up better than that weight suggested, perhaps partly because of the quality Easton Haven wheels. But on burly descents with big steps and drops, the weight gave the Mason a confident, solid feel while lighter weight bikes tended to ping-pong around a bit more.

Our Mason FS Pro is equipped with a SRAM XO1 11-speed drivetrain, a 34mm Fox Float fork, and Easton Haven wheels mounted with meaty Kenda Nevegal tires. It retails for $6,000. Diamondback also offers a more economical build, the Mason FS, for $3,500. With the same fork and shock and still solid SRAM X7/X9 groupo, it’s an excellent value for a great-riding bike.

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