This is the strongest ball joint Keller makes for the RZR XP Turbo S, and it will not fit a stock A-arm. The Mega uses a substantially larger housing and stud than the standard Keller joint — so much larger that the A-arm has to be machined to accept it. That is the trade: more material in the part that keeps failing, in exchange for a modification you cannot undo.
Read this before ordering: Mega ball joints require modification of your A-arms. If your arms are stock and you do not intend to have them machined, the standard Keller Turbo S joint threads straight in and is the correct part for you.
Key Features
- Oversized housing and stud — significantly more material than the standard Keller joint
- Two-piece threaded design, no OEM snap ring
- 4340 hardened chromoly steel housings and studs
- Adjustable, greaseable and rebuildable
- One joint serves both upper and lower positions on this platform
- Requires machined A-arms — not a bolt-in upgrade
- Limited lifetime warranty against manufacturing defects
- Made in USA
Built To Solve: Repeat Ball Joint Failure On A Turbo S
- Standard-size joints that keep failing on a car already running 32-inch tires from the factory
- 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
- Long-travel builds that outgrow a stock-size joint
- Riders who have already fitted heavy-duty joints and broken those too
Best For: Built Turbo S Cars With Modified A-Arms
- Turbo S and Turbo S 4 owners already running aftermarket or machined arms
- Dune and desert riders landing a heavy car hard and often
- Long-travel builds loading the front end beyond stock-joint capacity
- Tuned cars making more power than the chassis left the factory with
- Anyone having A-arms machined anyway and wanting the strongest joint available while it is apart
If your A-arms are stock, order the standard Keller Turbo S ball joints instead — same design principle, no machining required.
Specifications
- Material: 4340 hardened chromoly steel, stud and housing
- Design: two-piece threaded housing, no snap ring
- Housing: oversized Mega, larger than the standard Keller joint
- Serviceability: adjustable, greaseable and rebuildable
- A-arm modification: REQUIRED
- Positions: one joint serves both upper and lower on this platform
- Warranty: limited lifetime against manufacturing defects, original purchaser
- Manufacturer Part Number: BJKM-P-MTSPR (one joint), BJKM-P-MTSPR-K-2 (two joints), BJKM-P-MTSPR-K-4 (four joints)
Fitment
- Polaris RZR XP Turbo S: 2018-2021
- Polaris RZR XP 4 Turbo S: 2019-2021
NOTE: Mega ball joints require modification of your A-arms. Note that the four-seat Turbo S enters the fitment a year later than the two-seat car. Fitment is not guaranteed on applications not listed above.
FAQ
What actually has to be modified on the A-arm?
The Mega housing is larger than the bore a factory arm provides, so the arm has to be machined to accept it. This is permanent — an arm cut for a Mega will not go back to a standard joint. Have it done by a shop that has cut arms for these before.
Should I buy the Mega or the standard Keller joint?
If your A-arms are stock and staying stock, buy the standard — it threads in as supplied and solves the snap-ring failure just as completely. The Mega is for cars already running machined or aftermarket arms, or builds where the standard joint has failed under load.
Do I need different joints for the upper and lower positions?
No. On the Turbo S the same Mega joint serves both positions, so choose one, two, or a set of four for a complete front end.
Do these fit the four-seat Turbo S?
Yes, from 2019 onward. The two-seat car is covered from 2018.
Can these be rebuilt?
Yes. They grease and adjust, and the Keller ball joint rebuild kit for Polaris carries a Mega-specific option — make sure you order the Mega service parts, not the standard ones.
Is the Mega worth it on a stock Turbo S?
Usually not. On a stock or lightly modified car the standard Keller joint already removes the failure point, and it does not cost you a set of machined arms. The Mega earns its place on cars that have outgrown the standard part.
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 Mega is what happens when that design is taken as far as the geometry allows: the same threaded housing and chromoly stud, scaled up past the point a factory A-arm can accept.
Before You Order
Confirm your A-arms are machined for Mega housings, or that you are having that done. If they are stock, the standard Keller Turbo S joint is the right part. If the boots are torn but the joints are sound, the Keller boot replacement kit covers the Mega. If the joints are worn but the housings are good, the Mega option in the Keller rebuild kit for Polaris services them.
Installation Video
Official SuperATV installation walkthrough with Todd Keller: How To Install Keller Ball Joints
