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Front Upper & Lower A-Arms, Black: ARRMA 1/5 Kraton & Outcast

Item No. RPM81522
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5 out of 5 Customer Rating

Front Upper & Lower A-Arms, Black: ARRMA 1/5 Kraton & Outcast

Item No. RPM81522
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Product Details

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. These replacement front A-arms are designed with the backyard basher in mind and can handle some serious abuse and come back for more!
Key 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 and (1) RPM81562 For Completion Of The Front End
In The Box
  • (1) Upper A-Arm
  • (1) Lower A-Arm


RPM 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. RPM also moved the inner cross brace away from the chassis, eliminating the droop stop entirely. While this may seem counter-intuitive, the 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.

RPM 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. They 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 RPM's trademark blend of ultra durable materials, you can’t go wrong with RPM!

Version Notes:

RPM A-arms work perfectly with 8S versions of the Kraton and Outcast using ARRMA ARA330569 Spring Perches. EXB models using ARRMA ARA330740 Spring Perches may experience interference issues at both the shock mount and sway bars. RPM does not recommend the use of a-arms on these vehicles since modification of the a-arms may be necessary to eliminate bind at the shocks and sway bars.

Tech Notes:

RPM A-arms for the ARRMA Kraton 8S and Outcast 8S are sold as one upper and one lower in each kit. One left and one right 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 the materials.


  • 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 and (1) RPM81562 for completion of the front end

Product Specifications

Material Plastic
Color Black
Part Type Chassis Parts
Application 1/5 Kraton & Outcast