RPM Front Left Upper + Lower A-Arms Arrma Kraton/Outcast 8S
Brand: RPM
Part No: RPM81522
Backorder: Expected 18th June 2026
Request Stock NotificationEngineered for backyard bashing, the RPM Front Left Upper + Lower A-Arms (RPM81522) deliver a robust suspension upgrade with suggested compatibility for the ARRMA Kraton 8S and Outcast 8S. Their reinforced beam architectures curb unwanted flex while helping absorb the hits that come with hard landings and crashes.
The front lower A-arm uses a triple-beam layout, each beam measuring approximately 15.8mm tall by 9.5mm wide (5/8" x 3/8"). The inner cross brace is positioned away from the chassis and the droop stop is eliminated to help reduce the risk of chassis bending on extreme impacts. The front upper A-arm adopts a dual-beam design (about 12.7mm x 9.5mm / 1/2" x 3/8"), removes the tube over the hinge pin to lower moulding stress, and strengthens the leading-edge hinge pin support. Fingernail slots provide access to the aluminium support ring at the pivot ball (ring not included). Made in the USA. Lighter than stock by 4.5g per upper/lower pair.
Features
- Lighter than stock by 4.5 grams per upper/lower A-arm pair
- Suggested compatibility: replaces the front left upper A-arm from stock ARRMA ARA330561
- Suggested compatibility: replaces the front left lower A-arm from stock ARRMA ARA330589
- One vehicle will require 1 x RPM81522 (left) and 1 x RPM81562 (right) to complete the front end
Tech Notes
Each RPM81522 kit includes one front left upper and one front left lower A-arm. Suggested compatibility references: ARRMA Kraton 8S and Outcast 8S; replacement for ARRMA upper ARA330561 and lower ARA330589.
Installation Notes
Like the stock parts, the pivot ball holes are supplied without threads. If threading is difficult with the pivot ball, RPM recommends carefully tapping only 3–4 threads (tap not included). Do not tap further, as additional threads may negate the material’s thread-locking capability.
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The ARRMA Kraton 8S & Outcast 8S are 26 lbs. (12kg.) of high-flying, dirt shredding, jump-killing fun! If your A-arms aren’t up to the abuse these massive monsters can dish out, look no further than RPM. Our replacement front A-arms are designed with the backyard basher in mind and can handle some serious abuse and come back for more.
Our front lower A-arms have a triple beam style construction designed to spread impact energy across all three beams. Each beam’s cross-section is a whopping 5/8” (15.8mm) tall x 3/8” (9.5mm) wide. These massive beams reduce unwanted flex during normal suspension movement, yet allow impact-absorption during those not-so-perfect landings and crashes. We also moved the inner cross brace away from the chassis, eliminating the droop stop entirely. While this may seem counter-intuitive, our test truck’s chassis was bent at the droop stops, clearly illustrating that extreme impacts were too much for the chassis plate to handle. After all, there’s not much worse than a bent chassis.
Our front upper A-arms use a dual beam construction where each beam is a massive 1/2″(12.7mm) tall x 3/8” (9.5mm) wide. We eliminated the tube shape over the hinge pin to eliminate built-in molding stresses while beefing up the leading edge hinge pin support to add some much needed strength and durability.
Both upper and lower A-arms are molded with fingernail slots that allow easy access to remove the aluminum support ring (not included) at the pivot ball. Made in the USA from our trademark blend of ultra durable materials, you can’t go wrong with RPM!
Tech Notes: RPM A-arms for the ARRMA Kraton 8S & Outcast 8S are sold as one upper and one lower in each kit. One left (RPM81522) & one right (RPM81562) will be needed to complete the front end of one vehicle. RPM A-arms replace the upper A-arms from stock ARRMA ARA330561 and the lower A-arms from stock ARA330589.
Installation Notes:: Like stock A-arms, RPM Kraton 8S versions are sold without threads. If the pivot ball hole is difficult to thread using the pivot ball, RPM recommends thread tapping (tap not included) the hole for 3 – 4 threads, but do not tap any further. Additional cut threads will negate the thread-locking capability of our materials.
Features- Lighter than stock by 4.5 grams per upper / lower a-arm pair
- Replaces the front left upper A-arm from stock ARRMA ARA330561
- Replaces the front left lower A-arm from stock ARRMA ARA330589
- One vehicle will require 1 – RPM81522 & 1 – RPM81562 for completion of the front end
Key Info:
- Brand: RPM
- Part No: RPM81522
- Barcode: 672415815229
- Fitment: Option Part
Additional Categories:
Standard Shipping
£3.95 to most of the UK
Express Shipping
£6.95 to most of the UK
Worldwide Shipping
Available at checkout
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