Part 3: Why Start With Wheels and Seats?
I know what you're thinking: "Why is Fred showing us the wheels and seats of his Fun Buggy Project before he even has the chassis built?" Many folks consider these things final parts of the build, butboth are very influential to how your 4x4 works, and if you're building a buggy then they are an important part of how you design the chassis.
The seats of any vehicle are often overlooked and ignored since we would rather spend the money on suspension, tires, and drivetrain, but the fact is on any given trail run, having a comfortable, safe place to sit can be the difference between an enjoyable day in the dirt and craving a hard rock or log next to the campfire. There is also the serious consideration of safety. A seat you sit down in for lateral support, but which also has some sort of suspension for rough landings, can keep you behind the wheel and is less abusive to your body and back. Trust me, I've seen folks carried off on stretchers after severe rolls where their seats didn't protect their tailbones and spinal injuries resulted. I've been running a set of Mastercraft seats in my Chevy Army Truck, and believe them to be one of the best upgrades done to that truck, so I decided to repeat that choice for this project.
Wheels are often considered for either price or style, but more important to consider is their performance. Again I took my experience with running Walker Evans Race Lock bead locks on the Ultimate Avalanche and Super Duty and decided that these wheels have given near flawless results. But this time I wanted to take it further than just ordering up a set-I wanted something specific for the axle I built. So I visited the shop in Riverside, California, with my Dana 60 axles in tow and discussed what would work best and why.
Randy Anderson from Walker Evans Racing helped me consider some of the issues often ignored when getting new wheels. When the wheel turns on the steering axle it pivots around the kingpin or ball joints. My Dana 60s run kingpins so I will be referring to them ("Fun Buggy, Part 1" Aug. '05). If you imagine a line running from the under kingpin, through the steering U-joint, and out the bottom of the lower kingpin this is known as the steering pivot axis. My kingpin axles have a steering axis 8.7 degrees off of vertical. For optimum ease of steering you want that line to tough the ground at the center of your tire's contact patch. As you start moving that pivot point away from the center of the contact patch, you get scrub where a tire literally slides over the surface it is touching, and the distance from where the steering axis touches the ground to the center of the contact patch is known as the scrub radius. With a larger scrub radius you are not only putting more leverage on the steering components and forcing them to work harder, but also allowing more bumpsteer from obstacles as well as trying to force the tire on the inside of the turn to actually rotate backwards. When turning with a large scrub radius you also lose a certain amount of traction. Anderson noted that losing traction from a tire in one direction causes you to lose traction in every direction for that corner, which is a major concern on tight technical rock obstacles where you don't want to lose your line.
The Walker Evans Racing (W.E.R.) bead locks have a range of backspacing from 3 1/2 to 5 inches, and we determined that with 40-inch tires and 5 inches of backspacing we would have 4 1/2 inches of scrub radius, which is better than what most older straight-axle trucks came with from the factory. Plus this would still keep the hub of the axle inside the wheel's bead so it won't get caught on rocks and trail obstacles. Another concern is steering clearance so we measured back from the wheel mounting surface and found that with 17x8 1/2-inch wheels we would be fine with 5 inches and not get into the high-steer arms or tie rod or drag-link ends.
The W.E.R. wheels are made of pressure-cast aluminum and can be ordered with different backspacing and wheel bolt patterns. Our Dynatrac Dana 60s have 9/16-18 lugs with an 8-on-6.5 bolt pattern, and needed a 4 15/16-inch center hole. A program with these dimensions was quickly entered into the CNC mill's computer. W.E.R. has programs for just about every 4x4 lug pattern from Jeep 5-on-4.5 or Volkswagon buggy 5-on-205mm all the way up to Unimog 6-on-205mm.
Two issues that drive me crazy is having to use a special socket when changing a wheel, and having to use those long chrome lug nuts, so I discussed my options with Anderson and he happened to have these lug nuts from a Dodge truck with the proper 9/16-18 thread pitch I needed. Luckily, since I was going with 5 inches of backspacing, these lug nuts would sit flush with the front face of the wheel, have enough thread engagement, and still boast 1/2-inch of wheel between the 60-degree tapered surface of the nuts and the wheel mounting surface.
W.E.R. offers both Race Locks, which are for off-road use only, and its new Race Looks faux bead locks. I would like to thank all those folks running fake bead locks, even though some "extreme" wheelers may call you posers. I think it's great because now if I ever need to run my real locks on the street and happened to get pulled over I could just tell any local authorities who may consider them illegal that they are fake. On the W.E.R. Race Locks, steel threaded inserts are Loctited into the rim where the outer rings will be bolted on with Grade 8 bolts. Also note the step-down on the outside of the rim, which supports the tire better than some bead locks that simply clamp the tire and have the tire's bead riding on the bead-lock bolts.
With all the machining done, I decided to have the wheels sent out and powdercoated. Most folks like shiny polished aluminum or chrome rims, but I wanted a more industrial agro look for the Fun Buggy. With B&B Powder Coat right down the street from Walker Evans it was a short process to get a coat of gloss black applied (center). Powdercoating is different from painting in that the wheel is first masked off, and then a layer of colored powder is sprayed on and then baked in until a flexible hard surface is formed. The W.E.R. wheels can be powdercoated almost any color you can imagine, or you can get outer rings anodized as in the photo. I chose powdercoating since I knew the rings would become scratched and bashed in the rock and Bill Chrisman from B&B said that they could be recoated up to four times without needing to be completely stripped. In addition to the 17x8 1/2-inch wheels with wide rims, you can also order 15x8s for Jeeps and 17x7- or 15x6 1/2-inch wheels for desert or dune buggies with either wide or narrow 6061 T-6 aluminum bead-lock rings and choice of cast, polished, or powdercoated finish.
I'm not scared of spending hours on a hard metal seat, and have even done so for years while working the fields on the farm behind the wheel of an old Farmall tractor. But I'm also not going to lie and say it was fun. Since this is Fun Buggy, I figured being comfortable was an important step towards having fun for hours on the trail, so I went with some suspension-style seats from MasterCraft. From this cut-away view you can see how they start with a framework made of mandrel-bent and MIG-welded 3/4-inch mild-steel tubing. Then it is covered in a tight-fitting nylon-coated textile mesh that acts as the suspension, plus an optional lumbar support is available. Next the seats are cushioned with polyurethane foam of different thicknesses and density to get the desired shape.
I decided on the Sportsman model since it's what I have in my other truck, has a slight recline, and gives good lateral support without feeling too confined. I ordered a slider for the driver seat and lumbar adjustment, but color choices had me stumped. I liked the white vinyl MasterCraft put on its speedboat seats, but it didn't really go with my stealth industrial look. I also considered orange and black, but reconsidered when I realized it could become the Halloweenie buggy. Finally I decided on this mil-spec drab green color after seeing it on a friend's military truck. The Cordura fabric is resistant to dirt and designed to resist tearing from years of butt abuse, plus it should easily work within my design aesthetic.