One of the best improvements you can make to a Ford TTB (Twin Traction Beam) suspension is to replace the stock radius arms with extended (longer) radius arms. Some people buy extended radius arms from suspension companies, and some have built their own. What do they do, and why do people want longer radius arms?

Radius Arm Defined

The axle beam is secured to the trucks frame / crossmember with a bushing that allows the beam to move up and down and positions it laterally. The radius arm controls the axle beams motion in the longitudinal (fore-aft) direction. The radius arm is connected to the axle beam under the spring and connects to the frame with bayonet-style bushings.

Below is a picture of a Skyjacker extended radius arm (red) above a stock Ford Ranger radius arm.

Wheel Travel

The biggest reason for adding longer radius arms is to increase wheel travel. A longer radius arm will increase the amount of travel the suspension can achieve. This is because the extended arm will reduce the angle at which the suspension moves, allowing the suspension components to articulate more smoothly over a greater range. Essentially, the longer arm gives the suspension more leverage, which can help the front axle achieve a greater range of motion.

The specific increase in travel depends on how much the radius arm changes the geometry of the suspension, but generally, a longer arm provides more downward (and upward) wheel movement, increasing both droop (downward travel) and compression (upward travel) without increasing the amount of force needed to move the suspension.

When you’re off-roading, it’s really important to keep your tires on the ground. They don’t do you any good spinning in the air. I’ve encountered this problem on the 2019+ Ranger. I’ve had a wheel in the air and lost forward movement and had to back up knowing that my 1996 Ford Ranger would have continued forward with any problems because the front suspension with extended radius arms flexes enough to keep the tires on the ground. In the photo below you can see how the suspension is cycling to keep a tire on the ground.

This is another photo taken in the early 2000’s. The photo is small, but you can see how much wheel travel the suspension has allowing the tires to maintain contact with the ground. Looking straight at the truck, the front and rear suspension look like they’re making an ‘X’:

Pinion Angle

The longer arm can help reduce drastic changes in pinion angle during suspension movement, which can improve driveline angles and reduce vibrations, especially when lifted.

Caster

The other advantage of longer radius arms is that the larger radius causes the wheels to have less caster change. Caster angle refers to the location of your vehicle’s upper ball joint compared to the lower ball joint. If your upper ball joint or strut mount is located more toward your vehicle’s rear than the lower ball joint, your vehicle has a positive caster. Positive Caster provides better straight-line tracking which means you won’t have to turn the wheel as often to correct for divots and bumps in the road. Positive caster improves your vehicle’s responsiveness when rounding corners and improves your vehicle’s stability when traveling at higher speeds.

As you may have guessed, negative caster is the exact opposite of positive caster. When the upper ball joint is more towards the vehicle’s front than the lower ball joint, the vehicle has a negative caster which causes reduced stability and poor handling.

Ride Quality

I’ve seen it said online before that extended radius arms improve ride quality. Because the suspension can travel more smoothly, the ride may feel more compliant, especially in off-road conditions. While the longer radius arm does alter the leverage effect on the spring, it doesn’t reduce the effective spring rate by any significant amount.

Can I use The Radius Arms From An F-150/Bronco Dana 44 TTB?

Believe it or not, the beam section where the radius arm mounts are taller on the Ranger’s Dana 35 TTB than the F-150’s Dana 44 TTB, so you can’t mount Dana 44 TTB radius arms on the Ford Ranger, but you can use a Ford Ranger Dana 35 TTB radius arm on a Dana 44 TTB. The good news is that if you do have extended radius arms and move up to a Dana 44 TTB, you can still use your Dana 35 TTB radius arms.

Since the radius arm attachment on the Dana 44 TTB is about 1/8″ smaller, a washer or shim will need to be used under the top radius arm ear (The bolts are the same). The radius arm is also canted inward about 10 degrees or so. An angled shim can be made out of a coil spacer. This will ensure the coil spring doesn’t rub on the truck’s frame.

Aftermarket Extended Radius Arms

There have been a few companies that have offered extended radius arms for the Ford Ranger. Some no longer offer the arms, but you may still find them out there somewhere.

Companies That Still Offers Them

Skyjacker

Skyjacker has been the biggest provider of extended radius arms out there. Skyjacker actually changed their design from a steel tube design to a steel plate design. Here’s how Skyjacker describes their radius arms:

“Extended Radius Arms give you 30 percent better wheel articulation, improve your turning radius, gives better tire clearance, and less frame fatigue than caused by radius arm drop brackets. The bottom line is, in order to get maximum performance out of your lift, extended radius arms are a must. Kit includes mounting hardware, bushings and instructions.”

Below is a picture of the old-style Skyjacker radius arm (red) above the blue James Duff extended radius arm.

James Duff

James Duff is the other manufacturer of Ford Ranger extended radius arms that have been very popular. According to James Duff:

“When testing our vehicles equipped with Stage 1 Suspensions, we found that the stock radius arms were holding back our travel. Our solution: Extended Length Radius Arms. We’ve made our Radius Arms 15″ longer than stock, improving the front-end geometry after a suspension lift. This reduces the caster change on bumpy surfaces, making your vehicle more stable on rough terrain, increasing your suspension performance, travel and strength. This means that more bumps and holes in the road are absorbed by the suspension and aren’t felt as much in the cab. The drop brackets are adjustable for proper caster, depending on your lift.”

Prior to 2003, James Duff had been selling a different style radius arm. The 2003 and newer radius arm is a much stronger design. James Duff described those first radius arms as:

“Better turning radius, better ground clearance and improved handling all in one product! Fabricated with 1/4″ plate and 2″ O.D. heavy wall tubing, not reworked stock stamped pieces. Built in offset to clear larger tires on stock 4-1/2″ backspace wheels. At the frame, a massive 1″ bore high quality Rod End. Includes blue powdercoated arms, rod ends, bushings, heavy-duty replacement transmission crossmember and all necessary mounting hardware. All new parts, No core required.”

Autofab

Autofab has been making long wheel travel kits for the Ford Ranger For a very long time. I haven’t seen them list their radius arms as a separate item, but if you want a suspension with a ton of wheel travel, the Autofab kit will definitely provide it. The downside is that the kit is pretty costly. Autofab also has brackets to mount a Dana 44 TTB in your Ranger if you want to upgrade to a larger TTB.

Solo Motorsports

Solo Motorsports makes a beefy extended radius arm and will sell them separate from their long-travel kit, but the price may shock you. According to Solo Motorsports:

“We built our Radius Arms for maximum strength, durability, and articulation. This is achieved by using 1 3/4” x .120 DOM seamless tubing, 1/4″ 1020CR steel plating, and massive 1 1/4” heim joints. The horizontal tubes on these Radius Arms run on different planes to create a triangulation. Thus, adding a resistance to bending compared to other Radius Arms. Our Radius Arms allow the front wheels travel on a larger arc. Meaning that you will notice a smoother ride when going over the rough terrain.

Expect 12” of wheel travel in 4WD with our Dana 35 Mid-Travel Suspension Kit and up to 19” of usable wheel travel with our 4″ or 6″ over Long-Travel Suspension Kit, depending on tire size and other factors.

The factory frame hole is utilized for the Pivot Box placement and no welding is required during installation.”

Solo Motorsports also offers long-travel kits to put a Dana 44 TTB in your Ranger.

Companies That No Longer Offer Them

I want you to know what other companies sold extended radius arms for the Ford Ranger because you might come across a set of them either in a savage yard or from someone selling a set.

Rancho Suspension

Rancho was one of the first companies I knew of to sell a Ford Ranger suspension kit with extended radius arms. I don’t know when or why they stopped selling suspension lifts for the Ford Ranger, but I know by the end of the 1990’s they no longer offered them. I have heard that these arms break where the steel tube meets the flat steel plate area, but I’ve never seen it. I’ve also heard that the bracket that mounts the radius arm to the frame is the weak link and would suggest adding a gusset to give it more support.

Superlift

Superlift hasn’t made suspension components for the 1983-1997 Ford Ranger 4×4 for many years, but when they did, they sold a lot of kits. There’s a good possibility that you might come across their extended radius arms used. Here’s their description of their replacement radius arms along with a picture of one of their suspension kits including their radius arms.

“The Superunner replacement radius arms, available for both full and mid-size TTB Fords, offer caster correction plus additional benefits. The arms, considerably longer than stock, increase the amount of usable bind-free extension travel. This makes it easier for the tires to travel independently and stay in contact with the road or trail surface. The longer arms also reduce the degree of caster change the vehicle experiences as the suspension goes through its travel cycle. A longer arc of travel improves vehicle wheel rate as well. These factors combine to improve overall drivability and ride quality. You’ll experience a noticeable difference both on and off-road.”

Tuff Country

Tough Country offered a suspension lift for the 1983-1997 Ford Ranger 4×4. Their ‘Performance Lift Kits’ came with their tubular extended radius arms. I’m not really familiar with their kits and don’t know anyone that used one, but I welcome the input if you have any. Here’s how Tuff Country described their radius arms:

“Tuff Country EZ-Ride extended radius arms are designed for the off-road enthusiast. Extended radius arms provide better articulation, more ground clearance, and a sharper turning radius. These Tuff Country EZ-Ride arms are 15 in. longer than stock for more wheel travel and are angled inward to allow for better tire clearance. Rear mounting brackets use a pivoting axis mount to improve articulation.”

Making Your Own Extended Radius Arms (Overview)

The most common way of making your own extended radius arms is to cut the end of the stock arms off, add a section of 2-inch x 1/4-inch thick square tubing, insert the piece you cut off into the end of the tubing, and weld it all together. You should plug weld the stock radius arm to the square tubing and plug weld the section that had been cut off, and not just weld it around the end.

You should also box in the back side of the arm with 1/4-inch steel plate.

As far as how much longer to make them, typically you lengthen them 12-inches if you want to keep your radius arm mounts and transmission cross member separate, and 15-inches if you want to incorporate the mounts into a new transmission cross member.

The other factor to consider is camber. Probably the best way to set your caster would be to set the axle so the main part of the rad arm is horizontal (as it would be stock), then tack-weld the tube into the back of the arm at whatever angle is needed to reach the frame bracket properly. This should give you a caster angle of approximately 4-5°.

I’ve seen people use 2-inch x 1/4-inch round tube as well.

And then I’ve seen people get really serious and build them with 1-1/4 inch x 3/8″ DOM tube with a 2.63 Ballistic Joint on the end. I like how this arm has the gusset added to it. This not only helps secure the tube and radius arm together, but also gives it even more strength to keep it from bending.

If you want to run a joint of the end of your radius arm, Ballistic Fabrication offers tube adapters that you cab weld into the end of your tube and then screw the joint into.