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Rock Crawling - Fourth Year RCAA, First Year Modified Stock

Posted November 1, 2003

Opening The Season With A New Vehicle Class

As rockcrawlers continue to fine-tune their vehicles for competition, the results look less like trail rigs and more like buggies. In fact, the vehicles in the Super Modified Class not only don't look like trail Jeeps, but to be competitive, a considerable amount of money and time must be invested in them. So, when the Goodyear/Skyjacker Rock Crawling Championship opened its 2003 series in Reno, Nevada, this year, a new vehicle class appeared. Dubbed the Stock Modified Class, this new, entry-level class attracted 13 competitors. The Stock Modified Class limits tire size to 35 inches, vehicles must have OE grilles, no changes in stock axle width are allowed, and the wheelbase can only be modified by a maximum of 3 inches, with no manual controls. Spectators are entertained by extreme machines, but they can more easily identify with the Stock Modified Class.

The Stock Modified Class has been running in regional events, but 2003 marks the first time it has been open at an RCAA National Event. Beginning in 2003, RCAA, CALROCS, RCRC, and NARRCA organizations began using the same vehicle class rules for all three classes of rockcrawling: Super Modified, Pro Stock, and Modified Stock. By standardizing the rules, competitors can build vehicles for a specific class and compete in events in more than one series. The Super Modified Class is the extreme class. It's considered to be the open class; no minimum cab width, single or dual seats are OK, rear steering is allowed, and fenders are not required. This is where tube frames and replaceable body panels are considered usual. The Super Modified Class does have one rule: maximum tire size is 40 inches tall. Between the Super Stock Class and the Modified Stock Class is the Pro Stock Class. In Pro Stock, the vehicles must be equipped with a two-seat cab, and that cab must be at least 48 inches wide, otherwise these two classes are similar in every respect.

At the Goodyear/Skyjacker Rock Crawling events, the Modified Stock Class is mixed in with the Super Modified vehicles, and they run the same obstacles. Occasionally, an alternate route is marked to bypass a risky body damage area or a severe undercut ledge where 35-inch tires are not tall enough to pull the vehicle over without serious damage. To minimize confusion, the extra-credit routes that existed last year for the Super Modified Class have been eliminated.

What does it take to build an entry-level vehicle for Modified Stock? Select a lightweight vehicle that would require the minimum amount of modification and has an abundance of aftermarket upgrades available. The early '80s CJ would be at the top of that list. Modify the suspension to support 35-inch tires, install lockers in both axles, modify the transfer case for a front-wheel-drive-only option, and install a lock-up mechanism for the rear brakes (cutting brake). With a twin-stick mounted on the factory Model 300 transfer case, a front-wheel-drive-only option can be achieved. Install a 4:1 kit in the transfer case to provide Low gears without the expense of changing differential gears. Install lockers and upgrade all the axles in the stock differentials. Although points are deducted for using a winch, one is required. These modifications can be done for less than $4,000 plus labor.

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