Norco finally revealed everything that's going on with their radical downhill bike - the Norco Aurum HSP. Here's everything you need to know.
Norco's new Aurum HSP must be one of the worst kept secrets in the bike industry - even more so than SRAM Eagle Etap. Norco athletes have been seen ripping on their development bike for a couple of seasons, but only now have the Canadian company been ready to release it.
The bike hasn't been under wraps, infact it was raced for a full World Cup season, fine tuning the design. Norco worked directly with Norco Factory Racing to deliver the fastest downhill bike Norco has ever made.
Many of Norco's key attributes are on the Aurum HSP. The frame is full carbon for the best stiffness to weight ratio - and some added benefits of vibration damping. It saves 250g over the previous Aurum carbon DH frame. There's no alloy option - this is for pure race performance.
Norco use their Gravity Tune geometry. This means that regardless of the frame size, you've got a bike that fits the rider. This involves a rear centre that lengthens as you go up in frame sizes, and is shorter on smaller sizes. Norco do this with all their mountain bikes, from the Revolver hardtails up to the Range Carbon. Tubing is size-scaled too. Smaller bike? Thinner tubes. Bigger bike? Thicker tubes. This is done to maintain the same ride feel, no matter the frame size.
Norco have created the Aurum HSP in two wheel sizes - with 29" for M-XL and 27.5" for S-XL. Interestingly, the 29er uses 148x12 spacing out back while the 27.5" uses 142x12. Norco say this allows for the optimal chainline with SRAM 7sp drivetrains.
The suspension design is essentially a high single pivot, and at it's top point the rear centre is at it's shortest. So when you're unweighting to change direction, the bike should be the most nimble. Compress the suspension and the wheel travels on a rearward axle path. Partly so it doesn't stall on square edged hits but it also means on big hits the stability increases.
How about that idler pulley? The aim is to isolate the chain from the suspension design, to reduce pedal kick back.