Made in USA
Orem, Utah
Lifetime Guarantee
Unconditional
10 Colors
In-house powder coat
Fully Adjustable
0-6" of lift
3 X-Series Options
Only Core 4x4
RockJock's narrow style weld-on Johnny Joints for fabricators and suspension system builders offer up to 40 degrees of unrestricted movement in any direction as compared to 22 degrees on a common heim joint! Johnny Joint rod ends offer cushioning that a heim joint cannot provide via high-density urethane bushings that encase the inner ball. The heat treated center balls are cross-drilled for thru-bolt lubrication and the joint internals are retained with 2 heavy duty, heat treated side washers and a snap ring. The 2 1/2 in. narrow style outer shell is weldable CNC machined DOM tubing that is fitted with a zerk fitting for greasing. This specific joint's 70mm mounting width ball with a 16mm thru bolt hole is designed to fit the axle side of the 2021 and up Bronco's rear control arms.
| Brand | RockJock |
Reviews of Core 4x4
5.0
★
★
★
★
★
132 reviews
RG
Robert Van Gorder
Apr 27, 2025
★
★
★
★
★
Amazing service. Bought a track bar through Americantrucks.com and they sent it with the wrong size bushing sleeve. Korby at Core 4x4 was quick to get me the correct size and very responsive. Will definitely be using more of their stuff.
ZA
Zen Asher
Mar 23, 2025
★
★
★
★
★
The quality and durability of the arms are the best. They are super heavy duty. And lifetime warranty is crazy
SC
Singer Heating and Cooling
Mar 25, 2018
★
★
★
★
★
These guys are great. You can get them on the phone for support. This important and is not always the case with other custom parts builders. Their control arms are bomb proof and offer plenty of options. You can get real genuine Currie Johnny joints without paying the price for Currie arms.
L
luke
Mar 24, 2021
★
★
★
★
★
Excellent quality product and service. My l lower control arms broke and within the same day core 4x4 hooked me up with tier 2 arms and with the color I wanted. My Jeep rides better and has been solid for several months so far. 10/10 would recommend their products to anyone.
JT
jacob trice
Apr 27, 2025
★
★
★
★
★
Core 4x4 has outstanding products at a fair price and unmatched customer service. When you call Korby, it's like talking with a friend. Very cool and helpul!
I ordered some custom control arms, but from the wrong product line and they were super cool about returning them and upgrading to a better "Crawl" series. Only charged the difference between the two products. They paid all the return shipping and sent the uprgaded arms super quick. It was only a couple days. Awesome!!
I couldn't be happier with the transaction👍🏼
Also, these control arms are stout and take a beating. I run heck out my Jeep in the rocks and desert. No problems whatsoever.
Thanks Core 4x4, ya'll are welcome at my campfire anytime!
Jake T.
Pleasant Hill, Or.
MV
Mr. V
Mar 24, 2021
★
★
★
★
★
Good quality parts, much stronger than stock
B
Ben
Mar 24, 2021
★
★
★
★
★
2001 Wrangler TJ- i have purchased all front/rear upper/lower control arms. Front track bar and rear track bar. Quality is excellent and extremely durable you can tell its built to last. Bent a bolt on the front track bar and called and spoke with Spence. He immediately sent me out new hardware plus some! Product is amazing but what really separates companies apart is their service and these guys are second to none. Thank you all!
AM
Adam M
Sep 24, 2025
★
★
★
★
★
First time buying from Korby @ Core 4x4 and it’s being nothing short of a great experience. I bought the non adjustable Trail kit for my 5th Gen Ram 1500 with a 2” lift. The welds look great, nice powder coat finish and quality bushing. Had some trouble fitting the grease nipples due to the powder coating but a thread tap would fix that. They fit easily and perform great. I felt the improvement straight away. No more wheel hop on hard acceleration which was my main reason for the purchase.
I was missing some smaller bushings needed for the 5th Gen and Korby’s custom service was on point, with responsive emails and mailing out the missing parts straight away. Very happy with their products and customer service. Highly recommended company👌🏽
LS
Leonard Smith
Jan 22, 2026
★
★
★
★
★
I don’t write reviews often, but Core 4x4 absolutely earned this one.
I recently ordered leaf spring mounts and realized after the fact that I messed up my order. Totally my mistake. Instead of giving me the runaround or pointing at a return policy, Core 4x4 emailed me back and forth, worked through exactly what I was doing with my build, and made sure I ended up with the correct parts.
That kind of customer service is rare these days — especially in the off-road world where a lot of companies stop caring once the order is placed.
The parts themselves are exactly what you hope for: solid, well-made, confidence-inspiring hardware that looks like it belongs under a vehicle that actually gets used. You can tell these are designed by people who understand suspension geometry and real-world abuse, not just CAD screenshots.
Mistakes happen — especially on custom or modified builds — and Core 4x4 handled mine like pros. Fast responses, clear communication, and a genuine effort to help me get it right.
If you’re on the fence: don’t be. Core 4x4 is the kind of company you want backing your build — the kind that treats customers like fellow enthusiasts, not order numbers.
JJ
JT JT
Dec 23, 2025
★
★
★
★
★
We have all shopped places where the person on the phone makes you feel like they don't have the time to talk to you the customer or answer your questions. I can tell you first hand that's not Core 4x4. They have the best customer service I have seen so far. They have taken the time to respond to all of my questions in a very prompt and professional manner, taking the time to answer each and every question I have had. Lets put it this way if Core 4x4 sells a product I am wanting for my truck I will buy it from them, I highly recommend Core 4x4.
Your Dynamic Snippet will be displayed here...
This message is displayed because youy did not provide both a filter and a template to use.
Specifications
| Brand | RockJock |