Bodywork
Chromemoly - light and getting lighter...Bar-Work
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Here's a couple of pics of the 4130 tube (aka.chromemoly) used in the Rodeo's frame (well technically the first pic is not really part of the frame, but it's close enough). Majority of the tube is 38mm with some smaller diameters being used for hanging panels and miscellaneous bracing. The second image shows where the frame passes over the differential, incorporating a nitrogen-damped hydraulic bump-stop (A). Also shown, Dzus (supposedly pronounced 'zeus') quarter-turn fastener mounting plate ('B'), and the front of the rear sway bar (also 4130) at 'C'. The majority of the panels are thin aluminium plate. Each panel is custom made to fit a specific location on the car and usually contains integral Dzus fasteners. Thicker aluminium 'bash plates' are mounted under the car with bolts. In all, there are over 65 panels required to assemble the body. This does not include any of the fibreglass panels, of which there are another 7; plus a plastic grill and tin roof (both of which are stock Holden Rodeo parts!). |
Suspension Components
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Shown is the front-left lower A-arm and steering
knuckle. Both items are made from a combination of 4130 tube and
custom box sections. Note that there are no drainage holes in the
lower shock mount areas, which means these are particularly prone to filling
with water/mud. This is a bit sad, because the shock roseballs sit
in this water/mud and that's really the last thing you want. Of course being made of bare chromemoly, the car has a couple of drawbacks: 1. Any welding needs to be done with a TIG (Tungsten Inert Gas - Tungsten referring to the electrode on the welder work piece). 2. Being bare metal requires that the frame is completely stripped and rubbed-down with scourers after each and every race, together with a generous helping of an anti-rust agent like Penetrene. Note: if you hear anyone whinging about rubbing back chromemoly (i.e. this guy), just ignore him; it's bad, but it's not that bad. |
Roll-cage Certification
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Space-frame vehicles require CAMS certification of
the rollcage structure and engineering. This is a one-off process to
provide CAMS with some surety that the cage has a good chance of
withstanding a heavy collision. The usual test is to place a specified
weight on specific locations on the cage and measure deflection. It's somewhat ironic to think that it's deflection/distortion of the frame that will allow the occupants to survive a very heavy collision. So the main cage should be rigid, whilst the surrounding frame should be designed to 'give' on impact. |
Paint
Having scrubbed down the vehicle after a few races in 2006, we decided that a coat of paint was in order. The product we finally settled on is called POR 15, and combines an anti-rust agent with a tough finish (hopefully tough enough to withstand some of the punishment offroad racing delivers). Prep work includes a thorough scrub of the frame, a further scrub with a degreaser called Marine Clean, etch-priming with Metal Ready, and then application of the POR 15 with a low-pressure spray gun (pictured here). Not a bad finish (see below).
