It may look like an American Trophy Truck, but Hawke’s Bay racer Shayne Huxtable’s all-new unlimited class racer is all his own work.
Smartly finished in blue and black over white, and wearing fibreglass race bodywork in a Chevy style, #826 made its championship debut in early 2020 and won its class on debut.
Just a month later, the world turned inside out as Covid 19 also made its debut. So with the 2020 national championship cancelled after the opening round, Huxtable became the northern class 8 champion.
As lockdown rolled out, Huxtable turned his attention to what he had learned in that first event. From the outset, the truck has been a showcase for Huxtable’s engineering talents and those of his mate Tony Rickard. But the quiet of lockdown enabled the pair to work on fuel tank size and location, suspension tuning, a new front crash bar after the previous one tore itself to bits on the rear of a competitor’s car. Much of the bracketry for components are made by Huxtable, then spirited away to Rickard’s business, East Coast Powdercoaters, for finishing in gloss black.
Huxtable is not new to the sport. An accomplished and capable engineer, he has been around performance cars and off-road racing for almost a quarter century. He has built or rejigged a procession of unlimited off-road race cars and trucks over the years, creating ever-faster race vehicles as he went.
A soul-destroying fire at his workshop completely destroyed his previous truck and brought about an enforced break from the sport. But for Huxtable, as for so many who have raced at the top, there is no vaccine for the motorsport ‘bug’.
“Basically we’d had a few great ‘boys weekends’ away to off-road races and had a lot of time to talk through what we’d do if we built another one. And then it just got too much and we got into it.”
This time #826 follows the design of the big Trophy Trucks that race desert events in the USA. These things are the enormously fast and massively strong two-seater trucks that feature in the big Baja and Mint 400 endurance races. They are based on a tube chassis or spaceframe, and have enormous suspension travel. The engines are naturally aspirated V8 or V10 units making 560 kW (750 or more BHP) – and more importantly, huge torque. V8s producing 1000 Nm are commonplace.
Like most US off-road racing truck classes, full detailed plans to build the trucks are available on the internet. That made it simple enough to adopt and resize the plans to suit New Zealand, where the tracks are narrower and are either forest or farm based.
The truck was built over two years, working evenings and weekends and occasionally on slow afternoons at the workshop. The truck’s immensely strong spaceframe chassis was created by Huxtable in-house and is made of steel from Bissalloy in Australia.
“There weren’t many business days where the work allowed us to sneak in some build time, but we managed. We have built a Trophy Truck scaled down for New Zealand racing conditions, 300 mm narrower than the American trucks and 300 mm lower so it handles better. Now I’m thinking about a stadium set-up that is even lower so we can really push it on shorter courses. Then we’ll just crank it back up for rougher stuff,” said Huxtable.
The engine, Huxtable says, is “just some [Chev] LS stuff that was laying around the workshop”. But with a camshaft from Franklin Cams designed to maximise low-midrange torque, the 5.7-litre ‘hybrid’ LS engine has enough bottom end to make the truck jump off the rolling road dyno as the cam opens up.
“We didn’t really get good output figures from the dyno sessions, in fact the guy running the thing had never seen a torque profile quite like ours, so I just tell people that the power and torque are ‘enough’ – but we’re working on more power right now.”
The result is a unique, tough and sophisticated race vehicle that turns heads wherever it races. Both men are perfectionists and the truck build reflects this. Huxtable says the ‘finished’ truck will likely never actually be finished – already the body panels are being changed out, brackets modified, small tweaks made.
Next step down the drivetrain is a full-race ‘manualised’ Turbo 400 auto set up to Huxtable’s preferred specification. Where others opt for a ‘high-stall’ race setup, the truck runs low-stall, pairing the shift points with the engine’s torque profile. He has fitted big transmission coolers, knowing the enemy of any auto is heat.
“That makes it easy to get off the line and the trans itself is designed to handle 1000 BHP [745 kW] so it’s okay for now!”
The custom-built rear end is full race spec and runs a 5.8:1 Strange 10-inch diff head with 40-spline axles. The diff casing is – of course – powder coated. A four-wheel drive style ARB airlocker is engaged from the gearshift and gives better ‘bite’ to drive the truck out of tight corners. It is fed from an onboard air compressor and has been set up to engage under hard acceleration. Having an open diff allows him to also run wheel brakes then hit the ‘lock’ button when coming out of corners.
The suspension is based around Fox 2.5-inch coil-over main shock units with separate King five-bypass dampers. There are Yodaracing limit straps from Bryan Chang in Christchurch to give a soft ‘ending’ to the truck’s 20-inch front and 24-inch rear wheel travel.
Brakes are a mix of Wilwood rear calipers and strong Toyota Land Cruiser four pot fronts, though another change coming is to switch to Land Cruiser four pots all round. Race pads for these are readily available, as are parts and rebuild kits when needed.
Raceline beadlock alloy wheels are sourced through Huxtable’s cousin Glenn at US Procurements and the truck uses Goodride or Kumho tyres, switching out to hand-cut ‘prickle’ tyres in muddy short-course events.
Capping off the spec are ‘pumper’ helmets for both occupants to keep dust out of their faces along with a race radio setup. Minimal tools are carried: a screwdriver and a Crescent spanner.
“Mate, if anything happens that I can’t fix with these tools I’m happier doing it after the race. We’re there to race hard but above all to have fun.”
