With model names like Assault, Sortie, Mission and Recoil, there’s a military theme running through the Diamondback range. Hardly surprising then, that the frame material for the Diamondback Sortie Niner 2 is listed as ‘weapons grade’ aluminium.

Frame

In a nutshell, this frame is beefy. Every tube, pivot and link is oversized, and the overriding feeling is that this bike is bomber-solid.

At the heart of the Diamondback Sortie frame is the Knuckle Box suspension design with its massive triangulated link. Anchored to the down tube, the seam-welded link transmits forces from the seatstays to drive the rear shock. By manipulating the size and orientation of the link, Diamondback can tailor the suspension characteristics to suit the application — in this instance, delivering 115mm of rear-wheel travel.

Suspension

Supple at the start of the stroke for good grip and small-bump sensitivity, the Knuckle Box design also provides the right amount of ramp-up for mid-stroke support and bottom-out resistance — allowing us to run the rear shock in the open setting most of the time. Up front, Trail mode on the Fox 32 Float fork gave the best balance to the rear, and enough support without compromising grip or comfort.

Wheels

Swapping out the wire bead WTB tyres for our folding Maxxis control tyres reduced overall weight by over 1kg. But after only three rides the bearings in the rear hub felt rough, and the front was bone dry. Granted, the weather conditions were appalling, but we’d expect much better durability on a two-grand bike.

Groupset

After removing the wheels to fit our control tyres we forgot to flick on the Shadow Plus clutch on the XT mech and were surprised to find how much more chain-slap we got. 29ers are usually pretty quiet, so we can only attribute it to the chain hitting the low-slung seatstay, as the chainstay has a Neoprene guard.

Shimano’s entry-level brakes impressed. The lever action is incredibly smooth and light, resulting in consistent braking power and good modulation.

Components

Matching Easton finishing kit may bag the Sortie some bragging rights in the car park, but with all of the other bikes coming with 700mm-plus handlebars the 685mm Easton Monkey bar felt narrow.

Performance

First ride out on the Diamondback Sortie and the rear end of the bike developed an alarming amount of flex. We immediately checked that the 12mm bolt-thru QR was done up correctly; it was. We then grabbed a handful of spokes to see if the rear wheel had lost tension; it hadn’t. Basically, the main pivot had worked loose, and without the appropriate tools to tighten it the only option was to nurse the Sortie back to the van and swap it for a different bike.

With adjustments made to the pivot hardware, the Sortie frame proved stiff enough, but not so stiff as to justify the bike being 2kg heavier than the competition. With a substantial chunk of that weight locked into the wheels, the Sortie was slow to accelerate and more reluctant to make last-minute changes in direction. Point it uphill and the weight became even more evident.

Diamondback’s signature Knuckle Box suspension felt supple and controlled, but the weight distribution of the bike is too front heavy, so the fork ends up bearing the brunt of the load. As a result, when the front end broke traction, it happened suddenly and without warning.

>>> Click here to find out more about geometry with our handy guide

Verdict

Given its portly build, the Sortie ought to be the type of bike that you winch to the top of a climb, safe in the knowledge that you’ll be rewarded for your efforts with a ride that can slay the roughest descents. It isn’t. An overly steep head angle, more fitting on a XC race bike than a 15kg-plus 29er, means that the Diamondback fails to live up to its initial promise of being a back country bike to conquer all trails. In fact, as we discovered when the main pivot worked loose, you won’t want to venture far from the car park on your first outing.

MBR rating: 6

Specification
Frame: Weapons grade aluminium
Shock: Fox Float CTD Performance, 115mm
Fork: Fox 32 Float CTD Evolution
Wheels: Alloy hubs, WTB SX 23 rims, WTB Wolverine tyres
Brakes: Shimano M445
Drivetrain: Shimano M552 chainset, SLX shifters/front mech, XT Shadow Plus rear mech
Components: Easton
Sizes: S, M, L
Weight: 15.2kg (33.5lb)
Contact: diamondback.eu

Angle Finder
Size tested M
Head angle 70.7°
Seat angle 72.6°
BB height 332mm
Chainstay 460mm
Front centre 666mm
Wheelbase 1,126mm
Down tube 692mm

This review appeared in the January 2013 issue of MBR, alongside the Giant Trance X29 1, Scott Spark 950, Specialized Camber Comp and Whyte T-129s.

Want to know more about big-wheelers? Check out our complete guide to 29ers.