When you ask questions in the automotive world, you’ll discover that everyone has an opinion on everything.
One topic that receives some extra debate involves whether 4-links or radius arms are better as a suspension system. When you drive a solid-axle truck or SUV, leaf springs control its movement while suspending the vehicle. A coil spring cannot perform the same way.
That’s where the 4-links or radius arms debate states. They locate the axle, allowing it to move appropriately while driving. Both are stock options on several brands, with Jeep and Land Rover often chosen as the best examples.
Drivers can even upgrade both options, although the genetics and benefits of each choice won’t change with the extra dimensions.
Is there a clear winner between these two choices?
4-Links or Radius Arms: What’s Better?
Two primary suspension setups are available for vehicles with solid axles to use. You can select from the four-link system with Jeeps or the radius arm setup that Land Rovers typically use. Both options are excellent for off-road use, although the 4-link system is theoretically better.
Some people are opposed to the idea of using a link-style suspension. It often has to do with a more extended arm. When the pivot point is further away from the axle, the less pinion angle you get with travel.
That also means the front-to-back movement decreases. How can you go about the process of making the arm longer?
Since the average person doesn’t have the tools, skills, or knowledge to build a custom suspension, the best choice is to use extended length control arms that push the axle forward. This installation re-centers the wheels underneath the fender to prevent the tires from rubbing the cab.
You also have choices that can push your suspension system to the next level. When you have a radius arm design, a drop bracket creates the ideal geometry for up to a foot of travel in some vehicles.
If you invest in a hybrid system that offers more articulation, you’ll have more control in most situations.
Compromising on your suspension is the last thing you want to do. Since both options come stock, it’s sometimes better to shop for vehicles based on your usage instead of trying to update everything after the fact.
What Are Radius Arms?
Radius arms are devices that clamp to the axle’s housing. They attach to a single point on the chassis. Most of the products in this category are constructed from stamped steel, located on each side of the solid axle to ensure forward traction continues.
One of the best early options for the radius arms design was the first Ford Bronco.
By using two arms in the primary design setup, the axle housing cannot rotate or bind while under power. Although the front end unloads when force gets applied to create lift, you’ll see more of it with this design. That causes a traction problem when climbing a significant incline.
It’s also possible for the articulation to let the axle roll, creating additional issues for drivers to manage.
If you expect to be in your vehicle under extreme conditions, the radius arms option is not the best choice.
On the flip side of that equation is the fact that radius arms are fixed. Once they get installed, you’re ready to go. That makes them simple to make, install, and operate. They take up minimal space underneath your rig, which means pressing issues are rare with the oil pan or exhaust.
That’s where radius arms can have a significant advantage for some vehicles.
What Are 4-Links?
A 4-link setup attaches to the axle at two different points while also maintaining a connection to the chassis. The bottom portion locates the axle for its back-and-forth movement, while the upper links prevent it from free rotation.
Two different styles are available for the 4-links design. It can be triangulated or parallel.
If you have a parallel 4-link, the tubes attach with four forward links. They run parallel to each other toward a mounting point, with a Panhard bar mounted to the housing to handle the lateral movement.
When the triangulated setup gets installed, only half of the links attach to the axle tubes. The others run to the top-center of the housing, running directly forward to mount on the chassis. The center links run toward the outer links to create the shape designated by this option’s name.
The 4-link usually incorporates an adjustable sequence so that you can do whatever is necessary to modify your vehicle. That includes changing your pinion angles.
This advantage over the radius arms includes articulation and handling for off- or on-road applications. The triangulated choice provides the most benefits, but it is also the most complicated (and therefore expensive) to install.
Although the 4-link design comes with several benefits, it can also experience binding problems under extreme conditions. You’ll find the links running into the exhaust system frequently – and the occasional oil pan. The issue is manageable, but you’ll need to think proactively about ensuring you aren’t damaging the vehicle.
Tools Needed to Work on Your Vehicle’s Suspension
If you want to tackle some of the work on your suspension at home, it makes sense to have the tools available to get the job done.
Although you can purchase a basic wrench set almost anywhere, cheap tools often break or wear out prematurely. That’s why investing in a well-crafted set is worthwhile.
Once you have one of these tool sets at home in your garage, you can tackle almost any routine task while performing the suspension adjustments you want to achieve.
1. GEARWRENCH 300-piece Master Mechanics Tool Set
When you invest in this tool set, you’ll receive a full polish SAE with metric sizing. It comes with 84-tooth chrome teardrop ratchets with over four inches of swing arc for better movement.
It also delivers a 12-point set of long pattern combinations in both size options. When you have the GEARWRENCH 300-piece Master Mechanics Tool Set at home, you’ll be able to accomplish a lot in a short amount of time.
2. GEDORE 1007 Mechanic’s Tool Set
When you work as a mechanic, you need an entire set of hand tools to handle issues with your suspension. Instead of relying only on wrenches and sockets, you’ll find a whole collection of tools to have in your garage with the GEDORE 1007 Mechanic’s Tool Set.
It’s made in Germany by a company with more than a century of experience forging high-quality tools. It comes with hex keys, hammers, pliers, and spanners (and much more!) to handle almost any task that comes your way.
3. Milwaukee M18 FUEL Auto Kit
Although hand tools are helpful in many automotive situations, the different nuts and bolts on your vehicle can be difficult to remove under human efforts alone. If you have powerful tools available to handle the work, you can breeze through your suspension updates and regularly scheduled maintenance.
That’s what the Milwaukee M18 FUEL Auto Kit delivers with its dual impact wrenches. You’ll receive a 1/2-inch and 3/8-inch that offer a combined 1,600 foot-pounds of torque. It’s the most compact tool in the industry today that delivers these results.
4. Grey Pneumatic 29-Piece Deep Fractional Master Socket Set
When you have a tough nut or bolt to work on with your suspension, a heavy-duty socket is a tool you need to have lying around.
Once you start ratcheting the weight of this tool on the stuck component, it’ll start working its way free in no time at all.
With the Grey Pneumatic 29-Piece Deep Fractional Master Socket Set, you’ll receive a package weight of 84 pounds for only 29 sockets, indicating how strong this Taiwan-based product is for your automotive work.
Which Is Better: 4-Links vs. Radius Arms?
Although some people have ill feelings toward any stock equipment, the 4-links option is superior for those who need off-road applications. That doesn’t mean it’s the right choice for you. If you only go off-roading occasionally and have more of a commuter, the radius arms design could be more effective.
I don’t say this often, but I feel like the manufacturer chooses the 4-links or radius arms design for specific reasons.
If it didn’t work, the OEMs wouldn’t use that option. If you want several aftermarket options, the radius arms choice makes a lot of sense. Several products from Superlift, Rancho, or BDS can offer the advantages of a lifted suspension system with this kit.
Unless you plan on doing some serious wheeling and off-roading, the radius arms setup is more affordable and delivers a positive result.
If you need handling improvements, the 4-links system is worth the upgrade. It’ll provide better handling characteristics on the highway, which means you’ll see a massive performance improvement when you’re on the trail.
Even a standard street vehicle benefits from upgrading to a 4-link system from the stock leaf springs that often get used.
If I had to choose one, I’d select the 4-link system. It tends to be a superior design that handles everything the radius arms can manage while offering more advantages.
Although you need to watch the exhaust and other drawbacks, you can crawl rocks without hesitation when you invest in that upgrade.