Rock Spider

We should have seen this one coming. It could have been coincidence, but when Goodyear released its 40-inch MT/R at SEMA last year it gave the new competition tire the code name "Rock Spider." One look at Walker Evans' new S-10 truck and we're pretty sure where the name came from.

But it's not just the tires that make this truck unique. What sets this rig apart is its world-class fabrication and state-of-the-art technology that's been developed by Walker Evans Racing over the last 25 years and 64 off-road race trucks. Add in the radically new independent suspension design and technical support from some of the biggest names in the off-road world and this 4x4 is like nothing we've ever seen.

We had been hearing all kinds of rumors about this truck. And after persistent nagging by staffer Fred Williams we were invited down to Walker's shop in Riverside, California, for an exclusive first look at what we think will be a trend-setting rockcrawler. Designed and built by crewchief Randy Anderson and piloted by Walker Evans at this year's rockcrawling events, this new but familiar looking S-10 should be the one to watch. We'll have to wait till the first competition to see how it works, but we know that if we were competing against Walker, we'd be worried!

The Skeleton
Built entirely of chromoly tube that's been formed and TIG-welded together, Walker's latest S-10 uses a conventional two-seater, front engine, four-wheel-drive truck layout. The chassis appears very similar to Walker's last S-10 and uses the same suspension and pivot mount locations. The thinking is that this truck should climb at least as well as the previous solid-axle truck. It's hard to tell by this photo, but the engine, transmission, and transfer case were angled a few degrees to make room for the American Axle & Manufacturing driveshafts.

Independent Thinking
Many of you don't think independent suspension is meant for rockcrawling and are telling yourself right now that, "this will never hold up." Walker Evans Racing, in a joint venture with Dynatrac, is hoping to prove you wrong. This suspension design is based on Dynatrac Dana 60 centersections that are narrowed, bolted to the chassis, and fitted with 5.38 gears and Detroit Lockers front and rear. Unlike other competitors who are experimenting with A-arm-based independent suspensions, Walker Evans Racing and Dynatrac are using a hybrid swing-axle design that eliminates the reduced ground clearance and tire scrub that A-arm suspensions cause as they cycle.

The Missing Link
Until now no one had CV halfshafts that were strong enough to hold up to competition rockcrawling use. To solve this problem Dynatrac developed these new components based on 3-inch plunging shafts and 6-inch-diameter, fixed, ball-type CV-joints. The shaft itself is over 2 inches in diameter in the middle and necks down to 1.5 inches and 35 splines where it enters the differential. For comparison purposes the Delphi-made halfshafts GM uses in its 1-ton trucks are 1.4- inch, 33-spline, and the biggest H1 Hummer shafts are 1.375-inch, 32-spline.

Directional Control
For all the advantages the new suspension has it causes a few problems in the steering department. Walker's truck is currently set up to use two hydraulic rams, each one mounted to the steering knuckle from the control arm. The steering stress has to be isolated in the control arm or the hydraulic rams would try to straighten the curved arms. For now the two rams are plumbed to work together, but independent control of each ram could be possible. For those of you who didn't notice, the fabricated steering knuckles accept GM eight-lug IFS unitized bearing hubs like Walker used on his PRO-4 CORR trucks.

Powertrain
Walker's last S-10 used a Vortec 4.3L V-6 and a 4L80E four-speed automatic that was supplied by GM Powertrain's Hydramatic division for extreme-duty testing in his rockcrawler. To maintain a competitive fighting weight, this new truck runs an Ecotec 2.2L four-cylinder engine (rated at 140 hp and 151 lb-ft) mated to a two-speed Powerglide transmission that's been adapted to a 3.8:1 Atlas II transfer case. To avoid fluid leaks no matter what angle the truck is at, all drivetrain vent lines are plumbed into the tube chassis and breathe through a single filter mounted to the top of the cage.

First Obstacle
The truck was built in just over a month (kind of makes you feel slow, huh?) in the back corner of the Walker Evans Racing shop in Riverside, California, where it was kept out of sight of other competitors and off-road magazines. We were on hand to witness its first shakedown run and almost lost our minds when crewchief Randy Anderson had his guys jack the rear of the truck up to slip it around his office wall. There's almost 30 inches of ground clearance under the rear diff before the wheels came off the ground! We asked Jim McGean from Dynatrac if the halfshafts would bind under those conditions and he told us, "No, they will work at angles in excess of 40 degrees."

If you plan on competing against Walker Evans this year you better know what you are up against. Consider this your cheat sheet.