Polaris RZR 800 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 on a machine this age 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 RZR 800, RZR S 800 and RZR 4 800. On these machines 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
- Covers the RZR 800, RZR S 800 and RZR 4 800
- Limited lifetime warranty against manufacturing defects
- Made in USA
Built To Solve: RZR 800 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
- Original joints that have simply reached the end of their life on a fifteen-year-old machine
- 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: RZR 800 and RZR S 800 Front End Rebuilds
- RZR 800, RZR S 800 and RZR 4 800 owners refreshing tired original suspension
- Riders keeping an older machine in service rather than replacing it
- Trail and desert riders loading the front end hard on landings
- Owners running larger tires than the machine left the factory with
- Anyone 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#AG (one joint), BJK-P-RG-K-2#AG (two joints), BJK-P-RG-K-4#AG (four joints)
Fitment
- Polaris RZR 800: 2008-2014
- Polaris RZR S 800: 2009-2014
- Polaris RZR 4 800: 2010-2014
All three 800-class cars are covered, though each enters the range in a different year. Fitment is not guaranteed on applications not listed above.
FAQ
Why do RZR 800 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 these fit the RZR S 800 and the four-seat RZR 4 800?
Yes. The RZR 800 is covered from 2008, the RZR S 800 from 2009 and the RZR 4 800 from 2010, all through 2014.
Do I need different joints for the upper and lower positions?
No. On the 800 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.
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 800 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 800 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
