Shock Guide - From The Track To The TrailPosted in How To on February 1, 2008 Comment (0)
New stuff pops up on the trails every year during Moab's Easter Jeep Safari. From winches to crawler boxes, if it's new and exciting, it's bound to be in Moab on the trails the week before Easter. During EJS '07, Donahoe Racing's Class 3 FJ Cruiser garnered plenty of stares in Moab. The FJ, fresh off of a class win in the SCORE Baja 250, crawled just as well as it hauled. We watched as the FJ, in full race trim, competently conquered the creepy-crawly sections in Low range and flew over the faster sections in 4-Hi. What made the FJ work so well in so many different situations on the trail? It wasn't the beautifully crafted 4130 chrome-moly rollcage. It was the finely tuned long-travel suspension.
"Racing improves the breed" is a clich, but it's based in reality. Pounding over rough terrain at warp speed tends to bring out the best, and the worst, in suspension design. Products that hold up get developed and brought to market. Stuff that doesn't cut it gets dismissed.
This time, we'll delve into shock types, shock mounting strategies, and shock protection. Shock protection? Yes - in the form of bumpstops and limit straps.
If you happen to see Donahoe's FJ Cruiser on the trail, rest assured that the driver didn't take a wrong turn and stray from the racecourse. It may have been bred for high-speed desert competition, but on the trail it's still right in its element.
This particular Bilstein 9100 Series coilover is destined for Project TrailRunner, a long-travel 4x4 Ford Ranger built for high-speed desert use. 9100 coilovers are more robust than their younger-brother 7100 shocks. The 2.65-inch-diameter body holds a generous volume of oil for greater fade resistance. Smaller, lighter trail rigs are usually fine with smaller-diameter shocks such as Bilstein's 9100 Series 2-inch-diameter coilovers. What about air shocks? Experience has shown that air shocks should be reserved for super-light trail rigs and pint-size competition buggies. 4 WHEEL DRIVE & SPORT UTILITY Editor-in-Chief Phil Howell initially used a set of air shocks on a project TJ. The TJ's weight required a lot of air pressure to support the vehicle. The high air pressures translated into shocks that topped out (hit their full extension) merely pulling away from a stoplight - obnoxious. The air shocks were shelved in favor of coilovers, with much better results.