New Zealand gearbox bike builder Zerode has been making a rare but successful DH bike for several years and now it’s rolled out a more versatile, enduro trail machine, the Zerode Taniwha.
Structurally and mechanically it’s a very different beast to the alloy framed, twin chained, super-high-pivot-point big bike, but it shares the significant advantages and disadvantages of its Pinion heart.
Developed by two ex-Porsche engineers and keen mountain bikers, the Pinion P1:12 gearbox is an impressive piece of engineering. Inside the CNC machined case are two parallel primary and secondary shafts carrying the steel drive cogs. All the cogs are meshing all the time, but which two pairs are doing the driving is controlled by a sliding spindle that carries the engagement pawls.
While Pinion also builds 18- and 9-speed boxes, in this case there are enough options to provide 12 gears, each evenly spaced at 17.7 percent apart to give a total range of 600 percent. With the 30t chainring and drive sprocket used here that gives a top gear roughly on par with a SRAM 32x10t set-up, but a cliff climbing bottom ratio that’s literally slower than walking pace.
Apart from the cap that covers the cable clamping mechanism, the casing is completely sealed with special anti-tamper bolts so you can’t get inside ‘for a look’ and screw it up. All you need to do is change the 60ml of oil every 10,000km (it’s a simple tip out, tip back in job) and Pinion will back it up with a three-year warranty.
Other than the sturdy chain tensioner arm that tucks in behind the chainring out of the way there’s nothing external to catch on trailside rocks, get a stick wedged in to or somehow self destroy with bad shifting/adjustment. Instead there’s a dead straight chain line, which can use any chain you want such as the heavy duty 8-speed piece on my sample.
Zerode also offers the forged cranks here or lighter but more expensive CNC machined arms in a range of lengths. While it’s a 142mm rather than 148mm Boost back end, the back wheel can be built symmetrical for strength rather than being offset (dished) to allow cassette spacing.
The lack of cassette and rear mech weight at the end of the swingarm, plus a chain position that always runs through the main pivot also make a massive difference to suspension performance, which might be enough to help you overlook the downsides of the gearbox.
Even allowing a generous 150g for the crank axle, Pinion’s claimed 2,350g is 1,385g heavier than SRAM’s XO1 Eagle 12-speed transmission, which is the nearest gear range equivalent.
While the neat carbon fibre Zerode frame weighs just 2,700g (6lb) without the Pinion, the complete bike (without pedals) is a monolithic 15.32kg (33.7lb)! Turns out that’s not actually as big a deal as it sounds though, as the weight is as low and centred as possible. In fact it hops, pops and pumps like a good ’un.
There’s no escaping the fact the gears grind more the harder you load them. On the flat they’re an ignorable murmur and shifting is similarly slick and easy. You can even change gears while stationary. Start torquing hard, however, and there’s a real grind and rumble through your feet and knees. Stand up and attack a short rise and you’d think the tyre was rubbing on the frame or something was stuck in the chain.
Trying to isolate the efficiency loss of just the gearbox is hard, but compared to a bike ballasted to the same weight with a year-old SRAM 11-speed transmission, the Zerode obviously saps more effort on steeper climbs or power plays. The double cable gear shift is equally uncooperative under high loads, effectively locking out unless you hiccup the pedalling to grab an easier gear, which can kill speed and momentum badly.
Some of the ratio combinations introduce a serious lag and clunk before power pick-up too and trigger style gear changing, while braking is impossible with the twist shifter.
My gearbox was brand new though and Pinion assures me that shifting ease and gear grind will reduce as the various cams and cogs wear slightly and sharp edges become rounded. Ive had this confirmed by other independent testers I know too, but we’ll be revisiting the bike in a few months to check ourselves.
What we do know is that the Zerode is truly outstanding with gravity rather than gears providing the speed. With a 65-degree head angle and 445mm reach on a size large it’s slack but short-ish.
The UK build includes a Burgtec 800mm carbon bar, a 50mm stem and an optional £400 upgrade Fox 36 RC2 fork that feel spot-on through the wired and glued motocross style mushroom grips. What happens when you tip all that into a corner is remarkable though as the low centred gearbox weight literally adds several degrees of lean once you’ve got the confidence to grab them.
The gear-free rear end is outrageously sensitive too. I’ve never had a Fox Factory Float X shock feel better and it delivers the kind of seamless ground tracking and hyper rich HD traction feel you normally only get through a pro-tuned coil shock.
There’s no chain interaction either so you can stamp on the power through rocks without getting jacked up and launched over the bars and I never dropped the chain.
As I've said, the centred weight also makes it very 3D mobile for its actual weight and with no rear mech to worry about you can shave rocks, trees, gaps, etc a lot closer without ending your run. The carbon frame is impressively stiff too, with internal cable routing completing an almost silent ride outside of the power grind and occasional clunk as the cranks catch up.
In other words it’s got the giddy agility to chop and hip down the trail like a 4X bike, but it’ll silently flatten suicidal boulder fields, suck up serious drops and hook the most ragged, blown-out berms like a full-on DH bike.
My sample was doing this on a relatively pedestrian Maxxis Minion DHF and 25mm WTB rim wheelset too, so there’s potential to create something even more jaw dropping.
This article was originally published in What Mountain Bike magazine.