Short answer: If your leaf-sprung diesel hops, clunks or shudders when you launch hard or pull away with a heavy trailer, you're probably dealing with axle wrap. Traction bars tie the rear axle to the frame so the leaf springs can't twist into an "S" under torque. That keeps the axle planted and takes stress off your driveline.
What Is Axle Wrap?
On a leaf-spring rear end, the leaf springs locate the axle. When you put a lot of torque through the rear axle, the axle wants to rotate. That twists the leaf springs into an "S" shape, which is axle wrap. When the springs let go, they snap back, and that cycle is what you feel as wheel hop.
The more torque you make and the more grip your tires have, the worse it gets. A tuned diesel, a heavy trailer or bigger tires can all turn a stock truck that behaved fine into one that hops.
Signs Your Truck Has Axle Wrap
- Wheel hop or a violent shudder on hard launches
- A clunk or bang from the rear when you get on it or let off
- Rear-end shake when pulling away with a heavy trailer
- Driveline vibration under heavy throttle
- Repeated wear on U-joints, driveshaft parts or spring hardware
Why It Matters on a Diesel
Diesels make a lot of low-end torque, and most of the trucks we work on are towing, tuned, lifted, or all three. Every hop sends a shock through the U-joints, driveshaft, pinion, springs and mounts. Getting rid of the wrap protects those parts and gives you smoother, more predictable traction.
How Traction Bars Fix It
Traction bars, sometimes called ladder bars, run from a bracket on the frame to a mount on the rear axle. Once the axle is tied to the frame, it can't rotate under torque, so the springs stay flat and do their real job: carrying weight and soaking up bumps.
Quick note on rear coil springs
Traction bars are a fix for leaf-spring rear ends. If your truck has rear coil springs, which many newer Ram 2500s do, the axle is held by control arms and axle wrap shows up differently. Give us a call before you buy anything and we'll point you the right way.
FASS Fabrication Traction Bars: Built In-House
FASS Fabrication traction bars were designed by our lead fabricator, Spencer Ekstam. They took more than a year of design, prototyping and testing.
- Frame side: a 2.5" forged rod end with a polyurethane-supported spherical ball. It's quieter and lasts longer than a Heim joint.
- Axle side: a two-piece poly bushing with sleeve for durability and less maintenance.
- Construction: laser-cut and CNC-bent from 1/4" mild steel, then welded with a mix of robotic and manual welding.
- Design: a square adapter and bar with 10 weld seams/plug welds, for much more weld engagement than traditional round-tube adapters.
- Finish: overlays on the frame brackets and bars come standard. Custom powder colors are available, and we'll contact you after purchase to confirm your color.
Current FASS Fabrication fitments
| Truck | Product |
|---|---|
| 2011–2022 Ford F-250 / F-350 | FASS Fabrication Traction Bars – Ford |
| 2003–2012 Ram 2500 / 3500 | FASS Fabrication Traction Bars – Ram |
Have a different truck? We also carry traction bar kits from BDS, PMF, Fabtech, Kryptonite, McGaughy's and more. Check your exact year and model on the product page or call us to confirm fitment.
Who Should Run Traction Bars?
- Tuned or high-horsepower diesels that hop on launch
- Trucks that tow heavy and feel the rear shudder pulling away
- Lifted trucks on bigger, grippier tires
- Anyone tired of replacing U-joints and driveline parts
Installing Traction Bars at FASS Motorsports
Our shop in Washington, MO installs traction bars, lift and leveling kits, and the rest of what we sell. When you book, we'll:
- Confirm your year, cab, bed length and rear suspension so the right kit gets ordered
- Look at your current setup: lift, tires, tune and how you use the truck
- Install the brackets and bars, then check clearance through suspension travel
- Walk you through what we did when you pick up
Planning a lift too? Doing the traction bars at the same visit saves you a second trip. See our installation services.
FAQ
What's the difference between axle wrap and wheel hop?
Axle wrap is the leaf springs twisting under torque. Wheel hop is what you feel when they repeatedly wind up and snap back.
Do traction bars make the ride rougher?
A well-designed kit shouldn't make a big difference in normal driving. Ours use a poly-supported spherical rod end on the frame side and poly bushings on the axle side, which keeps them quieter and smoother than a hard Heim setup.
Will traction bars fit my lifted truck?
Fitment depends on the kit, your lift and your truck. Check the product's fitment notes or call us before you order.
Do I need traction bars on a coil-spring truck?
Traction bars are for leaf-spring rear ends. If your truck has rear coils, talk to us about the right parts for your setup.
Shop Traction Bars or Book Your Install
Shop traction bars or book an install at FASS Motorsports in Washington, MO.
- Phone: 636-429-7020
- Email: info@fassmotorsports.com
- Hours: Monday–Friday, 8 AM–6 PM Central
Thank you for shopping with FASS Motorsports | In God We Trust.
