Shock Therapy has been tuning trophy truck and buggy shocks for decades and been improving UTV shocks since the Rhino days. They’re all over every new UTV to hit the market, and ST has several products for the new Polaris RZR Turbo Pro XP and XP 4—from true dual-rate spring (DRS) kits to Fox Podium RC2 shock sets for base Pro XPs. We got a chance to check out a customer’s Pro XP 4 with Shock Therapy’s latest RZR Pro XP suspension upgrades, DRS and the new adjustable bar clamp (ABC) for the OEM rear sway bar.

ST’s DRS kit eliminates the collapsed upper shock springs and replaces the lower springs with rates tuned for the weight of your Pro XP or XP 4 with accessories like a winch, spare tire and carrier, ice chest, rock sliders, doors, roof/rack, wheel and tire size, and much more. ST also accounts for driver and passenger weight, terrain and driving style to customize the DRS kit, which includes eight springs, four silent cross-over rings and two front collars. ST’s new ABC is especially relevant for Pro XP owners, as it’s a major pain to change out the OEM sway bar with the new bodywork. ABCs allow tuning the stock bar by adding four new mounts for the links.

Polaris still resists cross-overs and true dual-rate springs because customers complain about the clicking when the top springs collapse. ST’s DRS with silent cross-overs eliminates clicking while greatly improving ride quality and performance. ABCs add even more control and ride tuning. Turbo S and X3 ABCs are coming soon.


The DRS kit uses springs made in the USA for ST and has a lifetime warranty against sagging. DRS kits increase ground clearance, ride height and bottoming resistance with longer secondary springs front and rear. Silent cross-over rings have grooves for O-rings that eliminate the metal-to-metal clank when secondary springs fully compress.

ST’s ABCs are precision two-piece clamps that bolt into the OEM sway-bar link holes, turning a non-adjustable bar into one with five adjustment options. Each ABC also has seven Allen-head clamp bolts for a solid grip on the bar, and adjustable ST sway-bar links attach to each trailing arm.


DRS springs are high-silicon steel to resist sagging, and the cross-over rings are two-piece for an easy install on Walker Evans needle shocks. On Pro XPs with Fox shocks, cross-overs are two pieces that thread on with the shocks springs and collars removed. Both styles are billet aluminum, and the included O-rings are impervious to UV rays, temperature and humidity. ABC clamps are also billet aluminum with black hard-anodizing and polished for mounting the billet-aluminum links. ST links are hard-anodized black with CO2 laser highlights and ST logo engraving. Link ends are 5/8-inch instead of 1/2-inch, plus they’re Teflon-lined for smoothness and durability.


Any RZR Turbo Pro XP owner will appreciate the improvements in handling and ride quality the ST DRS kit and ABC provide.


We tested the ST Pro XP 4 at the Boulders, a whooped-out OHV area in Arizona’s Sonoran Desert long used for testing trophy trucks. The ST Pro XP 4 stayed much flatter over the big whoops with reduced bucking, and the ride over chatter-chop was also much smoother. Best of all, the XP 4 was much more resistant to bottoming on big G-outs with the true dual-rate springs. Rates were much better than stock and compensated for the extra weight of the XP 4 roof, light bar, doors, door bags, seats, tires and wheels. ST’s ABCs gave us the option of tuning the sway bar for more squat under hard acceleration or less body roll in hard cornering.


Indeed, ride quality and handling are greatly improved with ST’s DRS system, and speed through whoops was increased. Ride height and ground clearance are also improved for rock crawlers and desert racers. Our only complaint was that the stock WER needle shocks topped out in front over big rollers, but we have driven other ST XP 4s with their ride improvement system (RIS) valving. RIS further improves ride quality and bottoming resistance, along with top-out control. We’d highly recommend all three: DRS, RIS ($799.40), and ABC.

CONTACT: www.shocktherapyst.com, (623) 217-4959

RATING: ★★★★★

PRICE: $799.40, DRS; $299, ABC; $449, ABC w/ ST links

See UTV Action’s report on the 2022 Polaris RZR Pro XP here: 2022 POLARIS RZR PRO XP | UTV Action Magazine

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