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Truck Shock Guide - Shock Test

Posted in How To on November 1, 1999
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Photographers: Craig Perronne
p24486large+1948 jeep flatfender+front view
For the braking test, we used a smooth hard packed dirt road. We accelerated to 30 mph and then locked up the brakes. The compression was measured by a Zip-tie on the shaft of the shock. We used the same stretch of dirt road for the acceleration test. With the Jeep in two-wheel drive we started out in second gear. The tires spun a little in most cases so the amount of lift would probably be increased if measured on pavement. For the braking test, we used a smooth hard packed dirt road. We accelerated to 30 mph and then locked up the brakes. The compression was measured by a Zip-tie on the shaft of the shock. We used the same stretch of dirt road for the acceleration test. With the Jeep in two-wheel drive we started out in second gear. The tires spun a little in most cases so the amount of lift would probably be increased if measured on pavement.
Our rocky section wasn’t particularly difficult. But it had enough large rocks to get an idea how well each shock would absorb the bumps of rockcrawling. The patch was located on a hill, so bumps and jars were accentuated by weight transfer. Our rocky section wasn’t particularly difficult. But it had enough large rocks to get an idea how well each shock would absorb the bumps of rockcrawling. The patch was located on a hill, so bumps and jars were accentuated by weight transfer.
The adjustment knob on the bottom of the RS 9000 could be damaged if hit by a rock. However, in most applications the shock can be installed with the knob protected. If it is damaged, it can be easily replaced. The shocks can be adjusted differently front and rear to compensate for weight differences or suspension stiffness. Rancho also offers two in-cab systems that allow you to adjust the shocks without climbing under your truck. The adjustment knob on the bottom of the RS 9000 could be damaged if hit by a rock. However, in most applications the shock can be installed with the knob protected. If it is damaged, it can be easily replaced. The shocks can be adjusted differently front and rear to compensate for weight differences or suspension stiffness. Rancho also offers two in-cab systems that allow you to adjust the shocks without climbing under your truck.

With all the shocks on the market today, it's difficult to pick what will work best on your four-wheeler. There are several manufacturers, various types of technology, and plenty of hype.

We contacted Rancho to get the three shocks that the company produces. It offers cellular gas shocks (RS 5000), manually-adjustable shocks (RS 9000), and the new self-adjusting shocks (RS X). All three of these shocks present distinct advantages.

To test them, we used a ’48 flatfender with a very modified spring-over suspension system. You might think it isn’t a good example of the typical four-by, and you’re right. However, its poor on-road-handling characteristics will give us more defined results than a stock or even a moderately lifted vehicle. It sways horribly in corners, partially due to the lack of sway bars. It dives when braking, and the front lifts under acceleration. It does, however, ride comfortably while going slow as well as at high speeds. All of this will be taken into account when putting each shock through its paces. Since the RS 9000 is actually five shocks in one (five different settings), we tested it on the most extreme settings (1 and 5). This covers the range of possibilities with the manually adjustable shock.

Sources

Rancho Suspensions
Lake Forest, IL

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