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CURING THE INFAMOUS BRONCO LEAN

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If you have the dreaded “Bronco Lean”, chances are you have recently replaced the coils with newer soft coils or you have replaced your “C” bushings. This lean can be measured at the bottom edge of the front fenders, bottom edge of front reflectors or any other handy place, making sure that any body damage or bad body bushings won’t affect the numbers. Quite commonly the lean is 2” or more in the front of the Bronco. The cure to this problem follows:

You must disconnect the entire front axle assembly from the Bronco. Disconnect and remove the front coil springs, disconnect the frame to axle brake line, disconnect the front housing breather line, remove the radius arm nuts from the rear mounts. Remove the rear bushings that are on the end of the radius arms. With a set of jack stands supporting the axle (under the front hub assembly on either side works good) lower the threaded end of the radius arms down so they touch the LEVEL concrete floor. It’s important that the floor surface is a level, flat surface. With a floor jack under the “pumpkin” or gear housing of the Dana 44 or Dana 30, this makes this step very easy. Look very carefully at the ends of the radius arms. Do they BOTH touch the floor at the SAME time? If one radius arm is touching the floor and the other is not, then this is the most common cause of your Bronco leaning to one side or the other. You must have both radius arms parallel to each other. Are the C bushings installed correctly? Remove them and check the writing on the inside of the poly style bushings to verify correct installation. This step is critical. If the c bushings were installed wrong, then improper installation could be causing the lean.

To correct the lean, you must loosen the 4 bolts that hold the radius arm caps on. Choose one side to start with. By loosening the cap bolts on this side almost all the way out and then tightening them back diagonally or slightly quicker at the top or bottom (try different ways), the c bushing will seat differently You can vary the distance off the floor of the offending radius arm by 2” or more by proceeding this way. However, sometimes you cannot get the end of the radius arm that you want closer to the floor (more parallel to the other arm), only farther off the floor!! If this is the case, then you must try to get the arm back as close as parallel to the offending arm and then tighten/torque the radius arm bolts. Proceed to loosen the cap bolts on the other arm and repeat the steps you’ve already tried on the first arm. It may take 5 or 6 times on either or both before you will get the arms parallel to each other. Keep trying. It is hit or miss.

The bushings are IMO, the main culprit for front end lean when new suspensions are installed and the lean is a new condition. Of course this method or example won’t solve your problem if your springs are bad or you have other front end problems. However, many Early Bronco owners have emailed me saying that this has cured the “infamous front end lean” in their Broncos.

By Brian Cooke, Courtesy of BroncoFix.com

CURING THE INFAMOUS BRONCO LEAN Read More »

New Product Release – T-Rex Evo Radius Arms

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DUFF TUFF UNLEASHES THE NEW T‑REX EVOLUTION CASTER‑ADJUSTABLE RADIUS ARMS

Knoxville, TN – June 2025 – Duff Tuff, the leading name in advanced Bronco suspension systems, proudly introduces its latest innovation: the T‑Rex Evolution Caster‑Adjustable Stock‑Length Radius Arms. Engineered for bolted precision and designed for adventurers, these arms are redefining how off‑road enthusiasts navigate lifted Broncos and classic F‑Series 4×4s.

Designed for Precision Driving & Tire Clearance

These stock‑length arms aren’t just a refinished factory replica—they’re built with a purpose. NO CORE CHARGES EVER Featuring a built‑in caster offset, plus 4.25° of fixed caster and an additional 6.5° of fine‑tuned adjustment, they offer unparalleled steering control and handling stability. And yes, they are 100% bolt‑in—no welding or frame alterations required.

Street & Trail Ready

Ideal for drivers who split time between daily roads and rugged trails, the T‑Rex Evolution supports stock height or up to a 6″ lift (8″ for ’78–’79 models) while accommodating tire sizes up to 37″—without rubbing or cutting.

Durable Build, Sleek Finish

Manufactured in the USA, each arm arrives powder‑coated in Signature Duff Blue or Midnight Metallic Black, complete with all necessary hardware, making installation straightforward and visually striking.

Broad Compatibility

Compatible with Early Broncos (1966–’77), Big Broncos (’78–’79), and 1966–’79 F‑Series 4×4s—and works flawlessly alongside Duff’s long‑tube headers produced since 2002.

Now Available for Pre‑Order

Announced this week, the T‑Rex Evolution arms are now available for pre‑order. Reach out to James Duff directly to place your order and be one of the first to evolve your Bronco build.

Buy Now >

What Makes the T‑Rex Evolution a Game‑Changer:

• Adjustable caster cam bolts – Tailor steering precision and return‑to‑center feel independently for each wheel.

• No welding or drilling needed – Straightforward bolt‑in install saves time and preserves original frame mounts.

• Optimized for lifted Broncos – Maintains a tight turning radius even with larger tires.

• Built‑in suspension flexibility – Adds articulation and a smoother ride without harsh factory bind.

• Made in USA with style – Rugged, reliable, and premium-finished—angles meet aesthetics.

Customer Notice:

These T‑Rex Evolution arms ship with head unit bushings, head units, and hardware included. If your Bronco utilizes cast “C‑caps” or dual-shock setups, specific components like spacers or cap mounts may be required. Additional accessories, such as C-bushings, lower coil retainers, and frame bushings, are available.

Recommended Pairings:

We recommend pairing the T‑Rex Evolution arms with its MS2020 shocks, Heim steer upgrades, and premium coil systems for a complete performance overhaul.

Ready to Take the Next Step?

To pre-order the T‑Rex Evolution Caster‑Adjustable Radius Arms or schedule a fitting session, contact Duff Tuff Sales directly through DuffTuff.com or give us a call.

“Our new T‑Rex Evolution – Caster Adjustable arm is now ready for pre‑order. Give us a call today to place your order.”

New Product Release – T-Rex Evo Radius Arms Read More »

What is a Performance Package?

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1973 Bronco with 2.5″ Performance Package, no body lift & 33×12.50″ BFG KO2

Boost Your Bronco: The Power of Performance Packages

If you love taking your 1966-1977 Ford Bronco off-road or just want a smoother ride, upgrading your suspension is the way to go. At DuffTuff, we’ve created different performance packages to fit your needs—whether you’re looking for better handling, more comfort, or serious off-road capability. Let’s break down what these packages can do for you!

1.5″ Performance Package

Want a simple upgrade that makes a big difference? This Performance Package gives your Bronco a 1.5-inch lift, improving ground clearance without making the truck too tall. It’s perfect if you want better handling for everyday driving and light off-roading. Our favorite part about this package is that it’s a perfect pairing for customers who are installing a coyote powertrain or a powertrain that requires a 2″ body lift, while still allowing to keep it as low as possible. It also has great steering geometry and requires very little welding.

Purchase 1.5″ System >

Huck with a 1.5″ Performance Package and 1″ Body Lift

Above: Left – 1973 Bronco with 2.5″ Performance Package, 1″ body lift, 35×12.50″ BFG KM3 Right – 1974 Bronco with 2.5″ Dual Sport 4-Link, 1-inch body lift, 255/80R17 Toyo Open Country

2.5″ Performance Package

This package gives your Bronco a 2.5-inch lift, making it ideal for both on-road and off-road driving. It enhances stability and comfort while giving your truck a more aggressive stance. Often called the “Wife and Kids Package,” this is our most popular option for those seeking a well-rounded upgrade. It allows you to cruise confidently on a Friday night, offering a smooth ride at higher speeds provided by modern powertrains. Plus, it provides a comfortable and controlled ride for camping or overlanding with the family in national parks over the weekend. Easily fit a 35″x12.50 tire with a 1″ body lift and fender flares. Don’t want to install a body lift? This system will accommodate a 33″x12.50 tire with flares.

Buy 2.5″ Performance Package >

2.5″ Dual Sport Monster 4-Link Performance Package

Ready to take your Bronco to the next level? This 2.5-inch lift system includes all the front suspension of our leaf-sprung 2.5″ performance package while featuring a dual durometer rear 4-link suspension, which gives you smoother movement over rough terrain and more confidence for control on the street with higher horsepower applications. It’s designed for people who love serious off-roading but still want a comfortable ride on the street. This system can fit the same tire selections as our 2.5″ leaf-sprung system.

Buy 2.5″ Monster 4-Link >

Above: Suzy and Hi Ho Silver 3.5″ Performance package and 2″ body lift 35×12.50″ BFG KM3

Buy 3.5″ Performance Package >

3.5″ Performance Package

Looking for more height and better performance? This 3.5-inch lift gives your Bronco extra clearance for larger tires and tougher trails. It improves handling while keeping the ride smooth, making it a great option for adventure lovers. Clear 35″ tires with ease with a cut rear fender and flares.

5.5″ Performance Package

If you want the biggest and baddest upgrade, this Performance Package is the way to go! With a massive leaf-sprung rear 5.5-inch lift, your Bronco will be ready for extreme off-roading. Equipped with long travel shock mounts it will give you the articulation required when heading off the pavement. It provides top-notch suspension control, so you can tackle any terrain with confidence. With a 2″ body lift a 37″ tire is totally possible with flares and cutting.

James Duff Long Travel Extended Radius Arms, Early Bronco - Duff Signature Blue

Hobby w/ 5.5″ Performance Package and 1″ Body Lift featuring a 36×14.50″ Super Swamper

Above: Left – Hi Ho Silver featuring 35×12.50″ BFG KM3 w/ 3.5″ Performance Package & 2″ Body Lift Right – 1973 Bronco Featuring 35×12.50″ BFG KM3 w/ 2.5″ Performance package & 1″ Body Lift

Which Package is Right for You?

  • For everyday driving and light off-roading: Go with the 1.5″ or 2.5″ performance package.
  • For serious off-road capability with comfort: Choose the Dual Sport Monster 4-Link.
  • For higher clearance and tougher trails: The 3.5″ performance package is a solid pick.
  • For extreme off-roading: The 5.5″ is the ultimate choice.

No matter which package you choose, you’ll get top-quality parts that make your Bronco ride better, smoother, and stronger. Check out our performance packages today and give your Bronco the upgrade it deserves!

What do the performance packages come with?

All of our performance packages come standard with the correct radius arms to match your lift height—T-Rex arms for lifts up to 2.5 inches and our Long Travel Extended Radius Arms for 3.5 inches and higher.

A key feature of our performance packages is our proprietary Hellwig front sway bar system, designed for better control and stability. This includes a heavy-duty lower coil retainer that allows either bolted or quick-disconnect options, ensuring your Bronco maintains its stance without lifting the front end after installation.

Each package also comes standard with a rear sway bar. For leaf-sprung suspension systems, we include a Hellwig rear sway bar with our quick disconnect system, while our Monster 4-Link System features a sway bar setup specifically designed for its advanced suspension.

To keep your Bronco steady at speed, we include our Bump Steer Eliminator System in a Tie Rod Over-the-Knuckle configuration, eliminating the need for a tight grip on the wheel during highway driving.

To enhance traction and control, our Torque Tamer system is available as an option for the 1.5-inch and 2.5-inch lift packages and comes standard with the 3.5-inch and 5.5-inch leaf-sprung systems. This innovative device prevents the softer Deaver leaf springs from flexing excessively under high torque loads, leading to improved acceleration and smoother gear shifts. By effectively eliminating axle wrap, the Torque Tamer ensures that your Bronco maintains optimal traction, providing a more stable and controlled driving experience both on and off the road.

Finally, every performance package includes our premium MS2020 shocks, providing exceptional handling and ride comfort whether you’re cruising the highway or tackling rugged terrain. Our 1.5″ and 2.5″ leaf-sprung lift systems have an option for our classic 70/30 shocks to allow for a plush ride.

From 1966 to 1977 we are your headquarters for classic Bronco suspension systems. Not sure if you are ready for a full performance package? Do you already have some of our components and want advice on the next steps to getting your Bronco to handle correctly? Contact us today.

Book an Appointment to Purchase
Buy 1.5″ Performance Package
Buy 2.5″ Performance Package
Buy 2.5″ 4-Link Performance Package
Hi Ho Silver - Colorado
Buy 3.5″ Performance Package
Buy 5.5″ Performance Package
Made in the USA

What is a Performance Package? Read More »

Super Celebration East 2025

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Check back for more information on what to expect for this year’s Super Celebration in Townsend, TN.

We’ve enabled our option to pick up at the show on the website. You will be charged TN State sales tax (9.25%) to pick up. Please pay extra attention when choosing your option at checkout.

If you need to speak to a Bronco Life Coach for assistance in placing an order you may schedule an appointment with our Bronco Life Coach at this link.

Super Celebration East 2025 Read More »

T-Rex Arms vs. Long Arms – What you Need to Know about Bronco Radius Arms.

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It still amazes me to this day how many Early Broncos still have stock radius arms. I have been to so many Bronco events and so many Broncos are lifted with 33″ and bigger tires and STOCK arms. Heck for that matter it amazes me how many Broncos have a “lift kit” and not a suspension system. There is a difference! Ok, let me backup for a sec. What is a radius arm? Look under a 1966-79 Bronco or even a 1964 to 79 F100 4×4 pickup. Take a knee behind the front tire and look under the body. You will see a bar that connects the back of the front axle to the frame rail under the door (just past the A-pillar). There is one of these on the driver and passenger side and they hold the front axle in place (front to back) at each frame rail. The front end is held on by what many people call a 3 link setup. Two radius arms and a track bar that is responsible for controlling (eliminating) side-to-side axle movement.

Why do we care about radius arms?? If you knew what I know you would care A LOT! This is not a sales pitch, It’s just the FACTS. If driving your Bronco, being in control, and enjoying the ride are important to you then continue reading because factory radius arms cannot do that when they stop being a stock Bronco. What does the radius arm do or in the case of a factory radius arm, what does it NOT do after your Bronco suspension is lifted over 2 inches?

T-Rex Radius arms shown for Early Bronco 1.5″ to 2.5″ lifts

The factory radius arm is naturally in a bind and once you lift the suspension it is put in a bigger bind which creates a harsher ride. The other issue is the length of the arm. As the suspension height increases the arm rotates the front axle forward and pulls it back slightly. This is a big problem because you need something called CASTER to make your Bronco drive really good down the road. The factory radius arm takes away all your caster when the Bronco is lifted. Some will argue you can add caster correcting C bushings and you can even add drop brackets at the frame. However, degreed C bushings and drop brackets don’t always fix the problem and sometimes can create other problems/issues to deal with. Plus, the other great virtue of a Bronco is its incredible turning radius. Well, what do we do when we add a lift…? WE ADD BIGGER TIRES! The bigger tires combined with a tight turning radius are going to now make those tires rub the radius arms in a tight turn. The noise and feeling is AWFUL. Everybody hates it but who wants to sacrifice their tight turning radius!? I know I don’t! It is one of the many things I absolutely love about the Broncos. So what is the solution? Duff radius arms! It is a no-brainer but first, you need to know which arms are best for you.

So, first, you need to decide if Duff factory length aka T-Rex arms or Duff Extended (Long) arms fit your Bronco best. You can’t answer that question until you know what the difference is and what each arm offers. Let’s start with the factory-length Duff arm first-

The T-Rex arm. Now don’t let this little guy fool you like he did me. I thought he was pretty useless at first glance. I mean look how short he is!? But this arm comes loaded with great features and fixes a ton of problems. In fact, its only real shortcoming (I kill myself) is it cannot flex/articulate as much as its big brother the Long arm. So, if your Bronco spends 70% or more time on the street and you aren’t looking to climb over big rocks and similar-sized obstacles or go really fast in the sand or the desert, then the T-Rex arm is a great fit for you. It can still do a lot of great off-roading with the added benefits of bolt-in application so no cutting drilling or welding is required. You get that awesome tight-turning radius back with those bigger tires. It is also worth noting, that ALL Duff radius arms are designed to free up suspension travel so they offer a softer ride. Do you really want to feel an amazing ride all around on your Bronco? Combine these arms with the Duff suspension and it is a GAME CHANGER. Still not sure which arm is best for you?

Midnight Series Black - James Duff Long Travel Radius Arms | Early Bronco
Extended Long Travel Radius Arms for Early Bronco shown above.

Let’s talk about the Duff Long Arm. The Big Brother to the T-Rex arm is almost 11 inches longer than a stock-length arm. This really is the do EVERYTHING radius arm for Broncos. But be prepared, it will require cutting, grinding and welding to install them as well as 3+ inches of suspension lift, the correct shock mounts and correct length shocks. Most Broncos using Long arms are running a 35 inch tire or bigger, wheeling on difficult (red & black) trails, going fast in the desert, and enjoying the whoops and jumps on the dunes. This arm also will make the on-road ride softer so a good shock like the Duff’s MS2020 and an aftermarket Hellwig sway bar may be required for panic situations to not lose control of the Bronco.  Another benefit the long arm offers for those who like whoops and jumps is the length of the arm reduces caster change throughout your suspension travel. 

NOTE: Both the T-Rex and Long arm utilize a second set of bushings at the head of the radius arm. These bushings allow articulation without all of the stresses to be the sole job of the C-bushing. This also allows for a smoother ride as it translates less sharp suspension movements to the vehicle and prolongs the life of the C-bushing.

Long Travel Shock Hoops for Early Bronco Long Arms
Long Travel Shock Mounts for Performance Packages
MS2020 Premium Shocks for James Duff Lift Systems

Which arm do I prefer? Honestly, I love them both but prefer the T-Rex arm on Huck my 72 Bronco which currently has 33’s and a 1.5-inch long travel Performance Package. Now, on a Bronco with a 3.5-inch lift and 35″ tire or bigger, I want the long arm. Both arms work great on other Broncos and trucks like the 1978-79 Broncos and F100 & F150 4×4’s from 1964 to 79. 

Let’s not forget how awesome the long arm is for solid axle swapping any Ranger-based vehicle from 1983 to 97 and all F-150s and Broncos from 1980-96. Heck, I’ve seen the long arm swapped into vans, cars with off-road chassis, and even J**ps! 

Which one is best for you is a question you can now answer. What’s even more important is you start making your Bronco the most fun to drive while being confident behind the wheel. The Duff radius arms and so many other great products they offer can do that, so what are you waiting for!? Get on the website today and make the best decision for you and your Bronco right now and be blown away at how much better your baby drives, handles and off roads. Below are links to our various offerings for the Bronco Platforms.

T-Rex Arms vs. Long Arms – What you Need to Know about Bronco Radius Arms. Read More »

Everything you need to know about Super Celebration East 2024

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We hope that you are as excited as we are for kicking off the show season with Bronco Supercelebration East, in Townsend, TN April 17th – 20th.

We’ve enabled our option to pick up at the show on the website. You will be charged TN State sales tax (9.25%) to pick up. Please pay extra attention when choosing your option at checkout.

Things you need to know:

  • We will have limited cash and carry parts, so we suggest placing your order beforehand. 
  • The cut-off to pick up at the show is April 10th.
  • Our storefront will be closed to local pick-ups the week of the show.
  • If you are only attending the throwback weekend, we suggest picking it up at the shop by April 12th.

If you need to speak to a Bronco Life Coach for assistance in placing an order you may schedule an appointment with our Bronco Life Coach, Zac C.

Check back to this post for updates as we head closer to the show, and make sure you are subscribed to our newsletter below for updates on items coming back into stock.

Subscribe to our Newsletter

Everything you need to know about Super Celebration East 2024 Read More »

November 2023 Updates

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We are making several changes to allow us to better serve our customers.

During the spring of this year, we implemented a VOIP software that allows our valued customers a place where they can quickly text message us. (865) 390-3833

On November 2nd, we will be moving our main phone number, (865) 938-6696, to this software. This will allow our salesman to work remotely as well as allow us to hire part-time employees for our Bronco Life coach position. If you are looking to apply, you can submit a resume to https://dufftuff.com/careers

Next, in order for our sales team to better serve you, we are asking that you book an appointment with our Bronco Life Coaches (salespeople) this will allow them to make sure they are available at a mutual time you select. You can view my calendar here.

Finally, we have made some changes to our freight calculator to allow us to deliver freight directly to residential customers. We have removed the FedEx terminal option. These new rates will be reflected at checkout.

I look forward to helping our customers with their builds moving forward into 2024. -Zac C. // Strategic Manager

November 2023 Updates Read More »

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