NORCO AURUM HSP C2 650B
£4,250 Is its performance as high as its pivot?
Designed as a purebred downhill race machine, the Aurum HSP was tested and developed by the Norco factory team on the Downhill World Cup circuit. It uses a high single pivot (HSP) with linkage-actuated shock, making it a very di erent beast from previous four-bar Aurums. But does that result in better performance on the track?
The frame
The 200mm-travel Aurum HSP is only available with a full-carbon frame, which has some smart design features. To keep sti ness and ride feel the same across all four sizes, Norco use ‘size scaled tubing’ – larger frames aren’t just longer, but also get bigger-diameter tubes with a slightly di erent carbon lay-up. The rear centre (e ective chainstay length) increases by 10mm with each jump up in frame size too, from 400mm (XS/S) to 430mm (L/XL), to keep weight distribution as similar as possible. You can fine-tune the front centre (distance from the bottom bracket to the front wheel axle) and the reach to suit you, using the provided adjustable headset cups (0, +4mm, +8mm).
That high pivot gives the bike a rearward axle path, to help maintain speed in the rough. There’s a chain idler to minimise the pedal kickback that’s common with this type of design and ensure the suspension stays as active as possible.
The kit
This is the cheaper of the two 650b-wheeled Aurum HSPs (there are two 29ers too). While there’s nothing on the spec list that’ll blow your socks o , it’ll all stand up to a good thrashing. The C2 is decked out in SRAM parts, from the GX DH drivetrain and Code R brakes to the RockShox BoXXer RC fork and Super Deluxe coil shock. Race Face provide the cockpit, and the bike rolls on WTB rims shod with Maxxis Minion tyres that do their best to keep you glued to the ground.
The ride
The Aurum HSP is a bumpswallowing machine. That rearward axle path helps it absorb anything the back wheel comes into contact with and, paired with the Super Deluxe coil shock, means it provides a supple and ground-hugging ride down the hill. The fork has to work hard to match the plushness of the rear end though, which is something we found the RC version of the BoXXer struggled to do. It’s the most basic model in the range, which uses RockShox’s simpler ‘Charger’ damper. We’d recommend upgrading to the more sophisticated ‘Charger 2’ cartridge. The rest of the components all worked well.
While the Norco’s geometry provides a stable ride, it does so without hindering its agility. We were impressed by how well planted our L/XL bike felt, while remaining manoeuvrable enough to keep the ride engaging. Even though the back end stayed stuck to the ground, it was easy to change direction.
We never noticed the rearward axle path disrupting our balance or riding position. One thing that is obvious is the chain drag of the idler, which makes pedalling more of a chore, though this is a price worth paying for the Aurum HSP’s bumpeating ability. This bike is happiest when charging full tilt into trouble, and you need a big hill to get the most out of it. LUKE MARSHALL www.evanscycles.com