And upgrades for even more performance


As our UTVs evolve with ever-more horsepower and performance, putting all that power to the ground becomes increasingly important. Wherever we go covering the UTV scene, we see a lot of machines that aren’t meeting their performance potential because they’re not set up properly. We went to Shock Therapy to see what they’re developing for the all-new RZR Pro Rs and Turbo Rs, the latest and greatest extreme-performance UTVs. We also picked their brains for the five things to do to any new UTV to get the most performance possible. Shock Therapy has also developed products to properly set up the steering, handling and suspension with performance upgrades.

For instance, only the new Pro R and Turbo R have true dual-rate springs with adjustable crossovers; all other Polaris UTVs have main shock springs and small “tender” or top-out springs. The OEM RZR springs start to sag within 300–400 miles, and Kawasaki KRX 1000 springs start to settle at around 700 miles. Every manufacturer tests in different ways, but all have to meet government test standards. Every production UTV must pass the “J-test,” where you drive said UTV on pavement at 25 mph and crank the steering wheel to full lock. If any tire comes off the ground, the UTV fails the test. It doesn’t make any sense to subject off-road machines to let’s-try-to-flip-it-on-pavement standards. ST has from day one had videos of J-tests with stock and ST-modified machines on their website.

Here’s the five things ST does with every new UTV that comes on the market.

ST techs use floor jacks, impact guns and Amazon spring compressors to adjust preload for installing ST’s DRS spring kits. A soft mallet and punch are used to loosen the preload locking rings.


Front and rear ride height are the important first steps in setting up any new UTV. Shock Therapy measures at the inner radius rod and lower A-arm mount. If you go from a 30- to 32-inch tire, add an inch to the recommended ride height.



When shock springs begin to sag, you lose proper ride height. The same goes when you start adding accessories and passengers. Each manufacturer lists ride height in the owner’s manual, and ST measures front and rear ride height at the lower/inner A-am and radius-rod mounts. Maverick X3 ride heights are 14.5 inches for 64-inch ds models and 15.5 inches for X rs and Max X ds models. The X rs Max ride height is 15.0 inches. Increase spring preload by lowering preload rings on the shock bodies to achieve proper ride height on both ends.

ST Dual-Rate Spring (DRS) kits have longer secondary (top) springs, and the website has an extensive list of parameters, such as passenger weight(s), what accessories are on the UTV, tire size, terrain, driving style, speed, etc. They come up with recommended spring rates for each customer’s DRS kit and have starting points for spring preload rings and crossovers. Each shock comes off and has both rings preset, then the DRS springs are installed. With shocks back on the UTV, an ST technician drives forward and back a few times to settle the car before checking ride heights. Amazon has spring compressors for $100 that make adjusting preload rings on the car much easier.

Once you have your front and rear ride height dialed, take a picture of the front and rear suspension arms at proper ride height for future ride-height checks. ST already has DRS spring kits for both the Walker Evans and Fox Live Valve versions of Pro and Turbo Rs for $999.95.

X3 Mavericks before 2021 have a problem with the outer toe-rod mounts loosening and destroying hubs. ST’s Toe Link Support kit strengthens the mount with this CNC-machined spacer and prevents hub damage.



Now that you have the proper ride height, it’s time to check front toe and adjust as necessary. ST sets front toe at 1/4-inch toe-in, and they have made toe plates for making more accurate measurements. First, they center the steering wheel and strap it down. Then they adjust both tie-rods equally to achieve 1/4-inch toe in, meaning the measurement at the front of the tires or plates is a 1/4-inch shorter than the measurement at the back of the tires or plates. Once that is achieved, ST measures each tie-rod to make sure they’re of equal length.

Especially with knobby tires, it’s important to use toe plates to check front or rear toe. Jason Weller checks rear toe here after changing rear shock springs and setting ride height; it’s that important for tracking.



Next, ST removes the front shocks and sets the jack to proper front ride height before checking toe again. With the jack, the technician raises the front end to full droop and measures toe, then lowers it to bottom the suspension and takes another toe measurement. The change in toe is bump-steer, and Ernie’s Pro R4 had 3/4 of an inch of bump-steer. ST is working on Bump Steer Delete (BSD) pins for the Pro/Turbo Rs and already has BSD pin kits for other RZRs, KRXs, Generals (all $119.95) and Can-Am X3s ($124.95), which are double-shear. They’re also working on BSD kits for Talons. Basically, BSD kits raise the outer tie-rod mounts to reduce or eliminate bump-steer, which causes the machine to fight the driver and even prematurely wear components as the suspension cycles.

ST has also developed Ultimate end-to-end tie-rods for extreme-performance UTVs. Adding to the BSD pins, the Ultimate end-to-end tie-rods have 5/8-inch outer rod ends and 7075 billet-aluminum tie-rods that are hard-anodized for strength and durability. A proprietary, heavy-duty inner joint strengthens the Ultimate tie-rods, and they’re made of 4340 high-carbon steel and are 20-percent larger than OEM, eliminating a factory weak spot. They fit all RZRs (except Rs), Generals, and the KRX 1000 for $299.95.

ST’s radius rods have left- and right-hand-threaded 3/4-inch rod ends, so you simply loosen the lock nuts and turn the barrel on the car to adjust toe (lower) and camber (top). OEM RZR radius rods aren’t adjustable.



Rear toe is also important, and all trailing-arm setups have adjustable rear toe via the radius rods. As with the front, you want 1/4-inch toe-in for optimum handling. Again, the tire-to-tire measurements should be 1/4-inch shorter on the front measurement than the rear measurement.

Pre-2021 Maverick X3s have single-shear outer mounts for the center radius rods, which control toe, and they tend to loosen and wallow out the rear hubs. When that happens, you get rear-wheel steering and loss of control, and you also get to buy new hubs. ST has X3 Toe-Link Support (TLS) kits to strengthen the area with larger 12mm bolts and CNC-machined spacers to create a double-shear outer mount. They have TLS kits for 12mm stock ball ends, and 5/8-inch and 3/4-inch rod ends for $99.95. That’s a lot cheaper than buying one or two rear X3 hubs.

Also, Polaris RZRs have rear radius rods with pressed-in rod ends, so they’re non-adjustable. Aftermarket radius rods let you adjust rear toe and camber. ST’s radius rod kits have 3/4-inch Teflon-lined rod ends, stainless steel spacers, and 1.250-inch 4130 chromoly tubes with left and right threads for easy adjustment. They start at $549.95 for the RS1. Again, make sure the rod pairs are exactly the same length.

Pro and Turbo Rs have toe links that run through the trailing arms with a fixed inner frame pivot and an eggshell-concentric spacer to adjust rear toe. ST feels this is a weak link that can loosen and cause rear-wheel steering, so they’re working on a stronger setup like the X3 TLS kit. Also, you can set rear camber with the upper radius rods; ST eyeballs rear camber to match the front at ride height.

ST has RIS valving dialed for the Pro and Turbo R Fox Live Valve and WER shocks, and the limit straps prevent topping out, especially with larger tires. ST is also working on a front torsion bar, adjustable aluminum side arms and aluminum T-bar links (not shown).



With ride heights, front toe, bump-steer delete, spring rates, rear toe and camber set, your UTV should steer, handle and soak up bumps as it was designed to. If the tires aren’t on the ground, you can’t achieve maximum acceleration, turning or braking. ST’s Ride Improvement System shock mods can and will give your UTV a better ride with more control. They modify shock pistons, compression and rebound valve stacks, damping adjusters, and even the Internal ByPass (IBP) ports on X3s and KRXeS IBP shocks. RIS kits are $599.60 (Talons) to $939.60 (X3s) should you want the best ride quality right off the bat.

ST limit strap kits have upper mounts that clamp to the shocks and two clevises that thread into the mounts. Straps mount to each clevis and the longer, lower shock-mount bolt with the spacer.


Once your suspension is dialed in, protect your suspension, axle CVs, and shocks with travel-limiting straps, especially if you’re racing or duning. When catching air, your shocks extend fully and top out with a clunk. Axle CV angles are extreme at full droop, too. Installing limit straps and adjusting them to prevent topping out eliminates clunking and reduces stress on axles and suspension components. Shock Therapy has limit strap kits for most UTVs and the new Pro and Turbo Rs front Fox Live Valve shocks for $269.95 a pair. They have billet-aluminum, laser-engraved upper strap mounts that clamp to the shocks; quad-layered straps; Grade 8 hardware; stainless-steel spacers; adjustable clevis; and tethers to keep the straps out of harm’s way when shocks compress.

ST has limit strap kits for all RZRs, Mavericks, Wildcat XXs, Talons, and Yamaha RMAXs and YXZs for $269.95 a pair. Most RS1 racers strap the rear shocks. RZRs with WER shocks are more prone to full-extension problems than RZRs with Fox shocks.

See UTV Action’s full test on the RZR Pro R here:  2022 POLARIS RZR PRO R ULTIMATE – UTV Action Magazine


Shock Therapy

23011 N. 16th Lane

Phoenix, AZ 85027

(623) 217-4959

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