HOW-TO: Upgrade your RZR suspension for cheap

As the extreme-performance UTV revolution brings us ever-faster 1000s and beyond, not everyone can afford to upgrade to the latest and greatest UTVs every year. As enthusiasts clamor for the latest 1000s, used RZR XP 900s flood the marketplace, and there are several ways to upgrade those 900s, like an aftermarket big-bore engine and long-travel suspension kits, so they’ll run with 1000s. The thing is, the more you spend trying to keep up with the Joneses, the longer it’ll take to save up for a 1000. Aftermarket shocks are another route, but there are several shock companies that can modify your XP 900 shocks to work like OEM XP1K units. Shock Therapy out of Wittman, Arizona, is one such company. Justin Smith claimed he could modify our RZR XP 900’s Fox Podium X shocks to work more like the XP1K. If the OEM XP1K shocks are a 10 and the worn-out XP 900 shocks are a 1, Shock Therapy’s valving upgrade raises the 1 to a 5, and their dual-rate Eibach spring kit raises the 5 to a 9 or 10. For $1400, less than the cost of one pair of aftermarket shocks, an XP 900 owner could rebuild all four OEM shocks and get a ride like the XP1K until they can upgrade to a 1000. Intrigued, we had to check it out.


Shock Therapy has been rebuilding and re-valving Trophy Truck, buggy and sand rail shocks for many years, and the company holds five patents and licensing agreements with shock manufacturers. Since more and more desert-racing teams use UTVs for prerunning and more, Smith and Sons started doing more and more UTV shocks over the years, and the XP 900 upgrade kits are by far the most popular. Shock Therapy rebuilds and re-valves Fox, Walker Evans, Elka and King shocks, and they’ve done 70 Wildcats as well.


Where Race Tech replaces the stock pistons with gold valves, Shock Therapy drills out the OEM pistons, shafts and adjusters for more flow, then deburrs before completely rebuilding each Fox shock with allnew piston, shaft, adjuster and reservoir seals, plus new reservoir end caps with Schrader valves. The new Stage 1 Ride Improvement System (RIS) compression and rebound valve stacks completely reworked damping to work with the new dual-rate springs. At $650 for four rebuilt and re-valved shocks, Shock Therapy’s XP 900 Stage 1 RIS valving includes labor, so it’s less expensive than Race Tech’s gold valve kits.


With the rebuilt shocks better than new, the next stage scraps the OEM progressive springs for Eibach DualRate Springs (DRS). Shock Therapy has a patent on its three-piece XP 900 aluminum crossover rings, and the OEM preload and crossover rings are pre-measured on the shock bodies for ride height and crossover to the higher-rate spring. The crossover rings also have large orange O-rings to eliminate any clicking sounds when the initial spring collar bottoms on the crossover. Last, the secondary spring is installed, and the OEM spring retainers complete the rebuild and upgrade to true dual-rate springs for $750. The $1345 Stage 2 total is a great deal, compared to $4000– $5000 for aftermarket shocks, and Shock Therapy has a stiffer, adjustable torsion bar for $550, but we didn’t opt for it. Also, because Walker Evans Racing shocks use 3-inch springs, the WER Stage 2 RIS/DRS is $1600.


Our spare pair of Fox Podiums were completely blown out before Shock Therapy made them better than new, so we did laps on ST’s test track to get a baseline. Then we installed the Shock Therapy Fox Podiums and did some more laps. The difference in ride quality was astounding and much smoother on the Arizona cross-grain terrain. As we adjusted to the new ride and hit G-outs and washouts harder, we went in three clicks to prevent bottoming the front end. Shock Therapy lived up to its claims and does great work at an awesome price. To transform your UTV’s ride and increase trail speeds, call Shock Therapy at (623) 217-4959 or check them out at

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