It sounds like a simple question: “Do I want heim joints or ball joints on my side-by-side’s A-arms?” Unfortunately, the answer isn’t so cut and dry. While most applications will be best served with a robust set of ball joints, there are certain reasons why you might want a heim for your set of A-arms instead.
A heim joint is a special joint also known as a spherical bearing. Basically, there’s a ball bearing with a hole cut through the middle that spins inside an outer ring. A bolt goes through the bearing and attaches to your spindle. The bearing swivels as your suspension goes up and down so that your camber stays within an acceptable range through your suspension’s full travel.
They’re very commonly used as tie rod ends but it’s important not to mix the two terms up. They’re both spherical bearings, but anything called a “tie rod end” is designed specifically for tie rods and typically not up to the more intense leverage and forces subjected to A-arms. When referring to A-arms, they’re known as heim joints in the US or rose joints if you’re in the UK.
The most common reason to put heim joints on your UTV is to get camber adjustment. Heim joints thread into the ends of compatible A-arms and use a jam nut to lock in place. That allows you to thread it in or out however much you want to change your degree of camber.
If you’re running a custom suspension kit and some new shocks that give you ridiculously long travel, you might be well served by heim joints. That’s because heim joints used with appropriate misalignment spacers can swivel much further without the risk of breaking. The bearing is very unlikely to pull out even at extreme angles.
Heim joints aren’t compatible with just any old A-arms. They need A-arms that are specifically designed for them. Once you decide to go with heims, you’re stuck with them. You might end up limiting yourself to just a few different joint options instead of the dozens of choices you get with ball joints.
We mentioned that they can swivel much further than a standard ball joint without any issues, but that’s the only point they get for strength. They’re much weaker than ball joints in every other way. Slam your wheel into a stump? A ball joint can handle it. Hit that jump a little too hot? A ball joint will survive hits like this that would destroy a heim. Heims are strong, but they’re not as strong.
Heim joints don’t often come with rubber boots to protect them. And even if they do, they’re prone to wear and damage from dust, water, and mud. If you want to keep using them, you have to clean them frequently and keep them lubed up with some WD-40. Grease will just hold onto more dirt.
Ball joints are pretty much ubiquitous on modern side-by-sides. They use a stud that has a ball at one end. That ball sits in a steel housing filled with grease and is protected with a rubber boot. They’re pressed into A-arms and secured with a clip. The stud can be threaded so that it attaches to your spindle with a nut, or it can attach using a pinch bolt.
Ball joints are stronger than heim Joints in almost every way. Even oversized heim joints can’t keep up with a good ball joint. When it comes to strength, you have a lot more options with ball joints as well. There are OEM replacements that will get the job done and upgraded ball joints that can handle just about anything. Either way, it takes a lot more shear force (that means slamming into rocks and trees a lot harder) to break a ball joint than it does to break a heim joint.
Ball joints are very protected from the elements. They have strong boots just like the CV joints on your axles. These boots keep water, mud, and dirt out. The result is a joint that doesn’t wear prematurely. Some, like our heavy-duty and super-duty ball joints, are designed to be serviceable. They can be disassembled, cleaned, repacked with grease, and adjusted so that they feel new year after year. If you plan on riding anywhere where things can get dirty, a ball joint is the right choice for you.
If your machine came with ball joints (which it almost certainly did), you’ll have an easier time finding and replacing a busted ball joint than you will a heim joint. And you’ll have tons of aftermarket options to choose from too.
This only affects a small percentage of riders, but if you have a suspension setup that allows for an enormous amount of travel, a couple of things could occur. At best, your ball joints could limit your travel and at worst, they could break while you’re riding. Most of the time this won’t be an issue, and all-inclusive lift kits are designed to make the best use of the parts you have.
The stud of a ball joint can pull out of the housing easier than the bearing on a heim joint. That doesn’t mean this type of failure is likely or even common, it’s just possible. It ties into the limited rotation too. If your suspension overextends, you could pull the stud out of the housing as it tries to rotate. At that point, you’ve probably already blown a shock and folded up an A-arm anyway.
Generally speaking, ball joints are a little more expensive than heim joints. A high-end heim will probably cost you half of what a high-end ball joint would. But in this case, you’re getting what you pay for in terms of longevity and strength.
It’s true, you can’t use a ball joint to adjust your camber. But there are plenty of A-arms out there that do give you full camber adjustment that still use ball joints. So, while ball joints don’t add a camber adjustment feature, they also don’t exclude you from adding that feature with different A-arms.
The choice is obvious for us—we love ball joints! UTVs are too rowdy and dirty for a heim joint to replace the job of a ball joint. Heims are good for lots of stuff, but they’re just not ideal for the off-road life.
So before you replace your suspension and go for an all spherical bearing build, take a look at your ball joint options. The dependability of the good ol’ ball joint is hard to beat.