The not-so-minor details
Norco Aurum 2012 frame
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Note about weight
Figure given is for the complete bike.
Dialled geometry. Excellent suspension performance. Superb attention to detail.
Cable rub. Low head tube.
When Norco released the Aurum DH, the downhill world released a collective ‘heck yeah’. Finally, here was an all new downhill bike from Norco, a bike that truly broke the mould, and it looked bloody good too.
A few months ago we chose the Aurum as our test vehicle for Shimano’s new Saint groupset – we had the bare frame and fork shipped over to Canada, where it was dressed up in brand new Saint finery. We could have selected just about any frame on the market, so why did we choose the Aurum?
Firstly, the Canadian connection. If you’re going to be riding in Canada, why not ride a bike that’s built for the conditions? Secondly, this bike read like a dream on paper – great geometry numbers and a host of frame innovations that signal a new era for Norco.
So did the Aurum live up to our expectations on the high speed roots, jumps and berms of Whistler? Yes it did. We’ve continued to ride the Aurum back here in Oz too (though not nearly as much as we’d like to!) and while it’s a probably more bike than our local downhill tracks require, it’s always delivered.
Here are the performance highlights and lowlights. NB. This is a review of the Aurum frame only.
Great shape: Norco have nailed the Aurum’s geometry in our opinion. It all starts well up front, with a 63.5 degree head angle. This isn’t as slack as some of the new breed (many of which run a 63 degree head angle), but it’s a sensible figure – any slacker and your average rider is going to battle to keep the front wheel gripping in flatter turns. The bottom bracket height of 355mm is bang on, placing you in the bike, rather than on it.
Low up front: While for shorter riders like our tester, the Aurum’s front end height was perfect, we’ve heard some taller riders wish the bike had a longer head tube. At 110mm, the head tube height is low, and the head tube is the same across all frame sizes. For taller riders, this results in feeling like they’re too far over the front of the bike when it gets steep. To compensate, taller riders will need either high-rise bars or a stack of spacers under the upper fork crown. Norco should consider a 130mm head tube length on larger sizes.
Gravity Tune: This is where it starts to get really interesting. Norco recognised a problem with the way downhill bikes are sized and potential issues around weight distribution that stem from this. With most bikes, the top tube length increases in larger sizes, but the chain stay length remains the same. This decentralises the rider’s weight. Norco’s solution is to use different bottom bracket / main pivot forgings for the different sizes, the effect of which is to lengthen or shorten the chain stay measurement.
Obviously we can’t comment on how this effects the ride in practical terms as we only tested the bike in a medium size. Still, it’s an interesting concept!
Attention to detail is fantastic: Norco’s attention to detail really shines, with excellent fine detail finishing, and slick implementation of many cool frame features. The simple integrated fork bump stops are one highlight, as is the integrated seat post clamp.
Stainless steel pivot hardware caps it all off. We’re especially appreciative of the quality here, as previous Norcos have been renowned for using ugly, agricultural pivot hardware.
We’re big fans of the Syntace X-12 rear axle system. It doesn’t protrude beyond the dropouts at all, so there are no dramas with clearance, and it all does up with just the one 5mm Allen key. You do need to make sure it’s done up tight though, ours rattled loose under heavy braking on two instances until we gave it a good runch nice and firmly. In the same area you’ll also find one of the neatest derailleur hangers in the business. It’s secured with a lightweight alloy bolt, designed to snap rather than bend the derailleur hanger or derailleur. Best thing is, there’s a spare derailleur hanger bolt actually screwed into the down tube.
Great suspension kinematics: The Aurum’s rear suspension is superb, and would be even better with a Fox shock. Norco concentrated on giving the bike a more rearward axle path than in years past, helping it become less hung up on square-edge hits that try to rob you of momentum. 200mm of travel is plenty, especially when the suspension rate is nice and progressive.
Pedalling performance is good too, even thought we opted to run very little compression damping on the Rockshox Vivid R2C rear shock in order to maintain responsiveness over Whistler’s infamous braking bumps. The shocks offers both beginning and end stroke rebound control too, and we kept fairly
Our 300lbs spring was perhaps a shade too stiff for our weight. A 250-275lbs would have been ideal, but we’d rather run things a little firm and have something in reserve for hard compressions than wallow in the mid-stroke.
We did find the Rockshox Vivid seeping a little more oil than expected. A bit of seepage is fine from a new shock, but this was prolonged over a period of days. It hasn’t made a noticeable difference to damping performance as of yet.
Cable routing needs work: We experienced more cable rub than we’d like on the Aurum, especially around the linkage plates and seat tube. The solution, we found, was to cross the rear brake line and gear cable over. This means that rather than rubbing on the frame, as the suspension compresses, the lines bow out away from the seat tube. It’s an easy fix. For 2013 Norco have apparently revised the cable routing, so hopefully it’s a non-issue.
All up, the Aurum deserves to be considered in the top tier of downhill bikes, alongside the likes of Trek, Giant and Specialized. Getting the Aurum frame only as we have here isn’t generally an option, but there are four different price points to select from in the 2013 range. In our opinion the Aurum 2 is the pick of the bunch; at a shade under $4000 it runs a full Shimano Zee groupset, BoXXer RC fork and a Fox rear shock. With the same genetics as our test bike, it’ll be a winner. [/private]