Polaris RZR XP 900 ball joints fail at the snap ring, not the joint itself. That thin clip is the only thing holding a factory joint in the A-arm, and after a decade of hard miles it deforms or shears under landings and the extra leverage of bigger tires. Keller ball joints remove it entirely — the two-piece housing threads into the arm like a nut and bolt. Hardened 4340 chromoly, greaseable, adjustable and rebuildable.
Todd Keller's original threaded design, covering the XP 900 and XP 4 900. On this machine the same joint serves both positions, so you simply choose how many you need.
Key Features
- Two-piece threaded housing eliminates the OEM snap ring
- 4340 hardened chromoly steel housings and studs
- Adjustable and greaseable for correct stud articulation over years of service
- Rebuildable — a worn joint is serviced, not replaced
- One joint fits both upper and lower positions on this platform
- Limited lifetime warranty against manufacturing defects
- Made in USA
Built To Solve: RZR XP 900 Ball Joint Pull-Out and Snap Ring Failure
- Snap ring shearing and letting the joint separate from the A-arm
- Clunking or knocking from the front end over rough ground and whoops
- Play in the wheel when rocked top-to-bottom on a jack
- Worn-out original joints on a machine that is now well over a decade old
- Torn boots admitting water and grit so the joint wears from the inside
- Replacing the same joint often enough that it has become routine maintenance
Best For: High-Hour RZR XP 900 Front End Rebuilds
- XP 900 and XP 4 900 owners refreshing tired original suspension
- Riders running larger tires or added lift on an older platform
- Desert and dune riders loading the front end hard on landings
- Owners who have already replaced a factory joint more than once
- Anyone rebuilding a front end who wants a serviceable joint rather than another disposable one
Because these machines are long out of production, most buyers here are doing a full front-end refresh rather than chasing a single failure.
Specifications
- Material: 4340 hardened chromoly steel, stud and housing
- Design: two-piece threaded housing, no snap ring
- Serviceability: adjustable, greaseable and rebuildable
- A-arm modification: not required
- Positions: one joint serves both upper and lower on this platform
- Warranty: limited lifetime against manufacturing defects, original purchaser
- Manufacturer Part Number: BJK-P-RG#AA (one joint), BJK-P-RG-K-2#AA (two joints), BJK-P-RG-K-4#AA (four joints)
Fitment
- Polaris RZR XP 900: 2011-2014
- Polaris RZR XP 4 900: 2012-2014
Note that the four-seat XP 4 900 enters the fitment a year later than the two-seat car. Fitment is not guaranteed on applications not listed above.
FAQ
Why do RZR XP 900 ball joints pull out of the A-arm?
The factory joint is retained by a snap ring seated in a groove. Landings and the extra leverage of bigger tires can deform or shear that ring, and once it goes the joint has nothing holding it. Keller joints thread into the A-arm instead, so there is no clip to fail.
Do I need different joints for the upper and lower positions?
No. On the XP 900 the same Keller joint serves both positions, which is why this product is sold by quantity rather than by upper and lower. Choose one, two, or a set of four for a complete front end.
Do these fit the four-seat XP 4 900?
Yes, from 2012 onward. The two-seat XP 900 is covered from 2011, so the four-seat car starts a year later.
Are these worth fitting to a machine this old?
That is the usual reason people buy them. A Keller joint is rebuildable, so on a machine you intend to keep running it is the last set of joints you should need to buy rather than another round of the part that keeps failing.
Do Keller ball joints require A-arm modification?
Standard Keller joints do not — they thread into the factory arm as supplied. The Mega version uses an oversized housing and does require machined A-arms, which is the main reason to pick one over the other.
Can these be rebuilt instead of replaced?
Yes. They grease and adjust, and the Keller ball joint rebuild kit for Polaris services them with a new cup, boot and pin when the internals eventually wear.
Why Keller
Todd Keller designed the two-piece threaded ball joint to fix the one part of a stock front end that keeps failing, and SuperATV now builds and backs the line. The design has barely changed because it does not need to: thread the housing in like a nut and bolt, use a chromoly stud, and make the whole assembly serviceable so a worn joint gets rebuilt rather than binned.
Complete Your RZR XP 900 Front End Rebuild
Before ordering, decide whether you are replacing a single failure or refreshing all four corners — the set of four covers a complete front end, which is what most XP 900 owners need at this point in the machine's life. If the boots are torn but the joints are sound, the Keller boot replacement kit is the cheaper fix. If the joints are worn but the housings are good, the Keller rebuild kit for Polaris services them. Tie rods and A-arm bushings are worth inspecting while everything is apart.
Installation Video
Official SuperATV installation walkthrough with Todd Keller: How To Install Keller Ball Joints
