Diamondback make a broad range of suspension bikes ranging from a couple of hundred quid up to a grand and a half. The XSL sits at the bottom of their mid-travel all-mountain range, but it's still really well equipped for the money, thanks to a basic but effective chassis.
The basic chassis layout is the classic single-pivot swingarm, which is well proven with over a decade of use. Diamondback have added a few tweaks to bring it nicely up to date, mainly in the use of hydroformed tubes to increase strength in specific areas. Moulded bulges are clear at both ends of the sloping top tube and the head end of the down tube. The bottom of the down tube is also ovalised for stiffness around the main pivot and crankset.
The two thick upright swingarm plates are widely spaced, with a big hollow brace pipe piercing them to add stiffness. The deep rectangular chainstays run back to thick plate cantilever dropouts, with slim seatstays triangulating the structure. A disc-specific rear end keeps things tidy and Crud Catcher mudguard bosses are a nice touch too. However, the welding is a little rough in places which betrays the low price.
Our sample bike came with an 06 spec fork, but the 120mm travel Suntour unit worked fine so the 07 version should do too. Lockout damping also helps stop bounce on long climbs, although rebound control tended to be slightly random. The rear shock is a 120mm Manitou Metel coil unit, which doesn't have lockout but has decent rebound damping to stop the bike bouncing all over the place. It does add weight compared to air shocks though.
Raleigh distribute Quad brakes, so we're not surprised to see them on the Diamondbacks they also manage. What did surprise us is the consistent control and reliable power from these cheap but more than cheerful hydraulic discs.
Truvativ Firex GXP cranks are also a surprise, not in terms of their proven and impressive performance but that they're here on a £620 bike when we've seen worse kit on bikes twice the price.
Shimano Deore takes care of gear shifting. The chunky treaded and well rounded Moto Raptor tyres get an extra boost from the usefully wide 28mm Mountain Pro rims, setting up a very surefooted performance whatever trail surface we were riding. Watch the QRs on the Quando hubs though - the cam action has no real lock so can still loosen even if done up super tight.
FSA cockpit kit is another tick in the 'impressive for the price' box, and its dimensions are spot on too. Even the unbranded seatpost is a neat design, with a hollowed-out head clamp. WTB's Speed V saddle is a well established classic, with a universally liked profile.
The XSL looks a stretched-out bike and the ride position is easily the longest here, with plenty of breathing space that cross-country riders (and tall bodied folk) will appreciate. The relatively slack head angle also makes for a steady, unfussy ride that naturally likes to head straight on rather than need constant correction.
The 73-degree seat angle keeps enough weight on the front wheel to stop it sliding out, and the stiff, oversized stem is short enough to make quick corrections if you need to.
Even with most of the preload wound on to the fork, it's a soft and responsive unit that sucks up rough trail sections comfortably. The rear shock is also very softly sprung, which means you'll use most of the travel over even relatively tame sections. Again, this is great for traction and cruising comfort, but as soon as you start flying sets of steps rather than just rolling gently down them, you'll find the limits of both ends very quickly. The soft springing is less of an issue under power though because the swingarm pulls down into the ground as you pedal, giving a connected and firm pedal feel through the top class cranks.
The cockpit and cranks are about the only stiff parts of this bike though, both frame and fork exhibit very obvious flex in all directions. The thin top tube and tall but skinny swingarm are the obvious visual twisting points when you put stress through the frame, but it feels pretty limp and noodley all over. We even managed to rub the chain on the tyre and get it to change gear when we hammered it uphill.