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  1. Anti-Sway Bars
  2. Roadmaster
  3. Anti-Sway Bar
  4. Rear
  5. Steel w Polyurethane Bushing
  6. 1-1/2 Inch Diameter
Roadmaster Rear Anti-Sway Bar

Roadmaster Rear Anti-Sway Bar

Item # RM-1139-147
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Anti-Sway Bars

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Minimize sway and driver fatigue by improving the stability and driveability of your vehicle. The bar on this sturdy, effective anti-sway system mounts to the rear axle and to the frame to balance weight transfer and reduce body roll. 1-833-496-1390 to order Roadmaster anti-sway bars part number RM-1139-147 or order online at Free expert support on all Roadmaster products. Guaranteed Lowest Price and Fastest Shipping for Roadmaster Rear Anti-Sway Bar. Anti-Sway Bars reviews from real customers.
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Roadmaster Anti-Sway Bars - RM-1139-147

  • Anti-Sway Bar
  • Roadmaster
  • Rear
  • Steel w Polyurethane Bushing
  • 1-1/2 Inch Diameter

Minimize sway and driver fatigue by improving the stability and driveability of your vehicle. The bar on this sturdy, effective anti-sway system mounts to the rear axle and to the frame to balance weight transfer and reduce body roll.


  • Minimizes side-to-side movement to improve overall stability of your vehicle
    • Lets you execute turns and quick maneuvers with confidence
    • Allows for a level ride, even on irregular surfaces
    • Reduces driver fatigue - minimizes effort required to keep your vehicle in line
  • Diminishes effects of crosswinds, passing motorists and shifting cargo
  • Designed to fit your vehicle and work in conjunction with its suspension system
    • Attaches to rear axle and to chassis - uses weight of axle to brace frame as it shifts in turns
    • Engineered to avoid interference with most popular aftermarket add-ons and accessories
  • Made with polyurethane bushings instead of the standard rubber variety for a longer-lasting system
    • Polyurethane is durable and resistant to damage caused by oil, gasoline and ozone
    • Less wear means less give in the system and better support
  • Constructed of thick 4140 chromoly steel for superior strength
  • Includes heavy-gauge mounting hardware, easy-to-follow instructions and bushing lubricant
  • Works with front anti-sway bar (sold separately) for absolute stability - available on certain applications only
  • Made in the USA


  • Bar diameter: 1-1/2"
  • Limited Lifetime Warranty

Roadmaster Anti-Sway Bar Installed

Benefits of an Anti-Sway System

The Roadmaster anti-sway bar does for side-to-side movement what a good pair of shocks does for up-and-down motion. You will notice a marked improvement in your vehicle's stability as the bar works to balance weight transfer and reduce body roll. The anti-sway bar acts as a link between your vehicle's frame and its rear axle, using the axle as a brace to more effectively balance the shifting weight of your vehicle as you maneuver it. Lubricated bushings allow just enough pivot and rotation to compensate for the pressure placed on one side of your vehicle when it goes into sudden maneuvers, hits crosswinds or encounters shifting weights.

Roadmaster Anti-Sway Polyurethane Bushings

Superior Construction

The Roadmaster anti-sway bar is made of 4140 chromoly, a chromium and molybdenum steel alloy. This type of steel is considerably harder and stronger than the standard 1020 steel that is typically used in anti-sway applications. In addition, the larger diameter of the bar increases its torsional roll stiffness. The result is a bar that is not only stronger than the competition, but also nearly 30 percent better at resisting sway. The polyurethane bushings and grommets used at the attachment points are durable yet flexible, ensuring that the system is neither so rigid nor so malleable that it becomes ineffective.

1139-147 Road Master Anti-Sway Bar - Rear

Installation Details RM-1139-147 Installation instructions

This Product Fits The Following Vehicles

Customer Reviews

Roadmaster Rear Anti-Sway Bar - RM-1139-147

Average Customer Rating:  4.8 out of 5 stars   (1238 Customer Reviews)

Minimize sway and driver fatigue by improving the stability and driveability of your vehicle. The bar on this sturdy, effective anti-sway system mounts to the rear axle and to the frame to balance weight transfer and reduce body roll.


I recently purchased a 2011 Itasca Cambria 28 with only 10,500 miles. Our first trip made it clear that I needed to stiffen the chassis. Unfortunately Roadmaster Anti-sway bars are backordered, and though you should put those on first, I just installed the Steering Dampener. Easy installation though you need to be careful about seating the bushings. The videos are much better than the printed instructions. Already see a big difference in how much tighter the steering is. Can't wait for the bars to arrive. Disappointed to have to wait 4 weeks.

One year later, we have put over 22,000 miles on our rig, and added new tires. The ride is so amazingly better than without the steering stabilizer, and especially the anti sway bars. These additions are absolutely worth the time and money. I would strongly recommend them. You won’t regret it.
Jose - 12/13/2021

2022 Ford E-Series Cutaway

i bought the front and rear anti-sway bars from you, they look really tough om my class c motorhome. I all so bought your sumo springs. with all of this my ride should be great. I also bought a steering stabilizer but from someone else it is a safe-t-plus i can drive down the road no hands on wheel. thank you for all the videos on your wed site and you tube. they where fairly easy to install had to crawl around on the ground under motorhome like videos showed a bit tight some places. But well worth it, thank you


We’ve had a few trips since we got the front and rear anti sway bars installed on our 32’ motorhome. My son in law does all the driving and he very strongly recommends these. He’s stated that they have made the driving less fatiguing.

2010 Ford F-350, 450, and 550 Cab and Chassis

This review is for the front anti-sway bar I received - the rear is on backorder. Easy to install. Can't believe how much of a difference having just the front anti-sway bar makes! I was a little skeptical of the claims. It is substantially larger than the OEM anti-sway bar. I like that Roadmaster includes the grease for the bushings and the red loctite.

Looking forward to installing the rear anti-sway bar once it arrives, plus the steering stabilizer.


Ordered front and back and steering stabilizer, the anti- sway bars were delivered and I had them installed, the steering stabilizer still has not arrived ordered in March.


Bottom line - Yes its worth it.
on 2018 THOR/Axis 25.5

Night and Day driving.
Local shop in Maryland installed for me.
(I had already packed my tools/jacks for moving south).
Their mechanic was impressed with the size over the OEM.

On a related note, got the rear set up as well and running Sumo Springs.

This should be an OEM item, not an add on. Now to upgrade the shocks.
Lowell H - 02/27/2022

2022 Ford E-Series Cutaway

If you have a C-Class Motorhome you need these. I installed the front and rear sway bars along with the summon springs. I did not feel safe and thought that it was dangerous driving with the stock ford e350. It was night and day difference. I wouldn't have thought of letting my wife drive. Now I would and even crawl up in the bunk and take a nap. etralier had everything I needed and shipped in a timely fashion.


Product arrived quickly as usual with etrailer. The etrailer video was more handy than the accompanying instructions from Roadmaster. etrailer provided videos for both the early E450 and the later chassis installations. While essentially the same, there was a small difference of enlarging an existing hole on the early frame in my case a 2006 and having to measure to locate the hole on the later. It would be nice if Roadmaster included a parts diagram to help with assembly instead of small not clear pictures. I thought the parts package was short two half inch washers, I supplied them from my stock. The fittings on the Roadmaster bar are much heavier than the stock components. Installation is on a 2007 Coach House, motorhome. Took it for a test drive, big difference in handling.


Helped with sway, the e350 camper chassis needs a lot of work to get it to drive properly.
Sway bar helped, but still was not happy with how it drove.
Traded for a e450, which drives better.

The e350 would benefit with a Roadmaster Reflex Steering Stabilizer item # RM-RBK24-RSSC
Roadmaster Reflex Steering Stabilizer with Mounting Brackets for Class A and C Motor Homes
because it mounts between the chassis and the steering mechanism which produces a tight connection that reduces wander. A front anti-sway bar like item # RM-1139-176
Roadmaster Front Anti-Sway Bar
can be used with the rear in some cases such as this and handling the ride will be even better.
-- Etrailer Expert Sierra K - 05/04/2022


The anti sway bar significantly improved vehicle performance


The stock sway bars on the Ford E450 cutaway are trash. After replacing both the front and rear sway bars the RV handles like a dream.


This is a high-quality product! Well-engineered, high quality produced parts and performed as advertised and made a big difference in the handling.


This product has performed exceptionally. We experienced extreme winds without significant lane-changing effects on Wyoming highways and very little side to side drift when passed by large trucks. I installed the front sway bar without too much effort but the rear bar was a bit more difficult to install so I had a local Mechanic do the work. I’m very pleased with my purchase.


Easy review!!
I bought both front and
rear sway bars and the front stabilizer shock and it made driving my Coachman Class C so much easier to drive. Just these upgrades alone are worth the investment. Me and my elder dad installed it with ease.


Easy install, huge difference in handli ng.


Not sure if it has really improved the ride or not. Not confident it was installed correctly. (etrailer did not install it)

The point of this item is to minimize sway and driver fatigue by improving stability, so you should notice some change with it installed. Here is a video of an install that should be similar to your 2017 Thor Quantum Motorhome:
-- Etrailer Expert Sierra K - 01/12/2022


The Rear Anti-Sway Bar Kit for my Thor Four Winds (31') on a Ford E-450 chassis came with everything needed to do the install. The kit consists of high quality replacement parts and hardware along with installation instructions. The sway bar was easily installed. The on the road difference between the Ford sway bar and the Roadmaster was apparent immediately during the test drive. It greatly reduced that body roll experienced during cornering and improved the vehicle handling.


Upgrade almost complete on my E450 Quantum LF31. Not hard to install the items. Only have the rear sway bar next month and upgrade will be complete. I also have air bags on the back which helped with the weigh transfer on the unit.


Was easy to install and stabilized the RV significantly.


Love the improvement!

2022 Thor Four Winds Motorhome

I just had them installed and what a difference! No more rocking or swaying.


Well worth the money.


Product works as advertised. Virtually eliminated sway.
Driving the RV is now a pleasure.
etrailer always delivers and has knowledgeable people ready to help with advice .

After a year seems like longer I am still delighted with the improvement the bars made on the handling of the motor home. If in doubt spend the money. I don’t think you will regret it.
Randle - 04/12/2021

2022 Jayco Redhawk Motorhome

Was helped in a timely fashion and received my items quickly as well. Sales people were great to deal with and they have a great music selection while on hold...NO Elevator music


Sway bars on my Thor Axis 24.1 made it handle better. We tow a 20 foot race car trailer. Very stable. Connecticut to Road America, Elkhart Lake, Wisconsin - 19 hours.

Good product - improved stability for regular driving and in winds too.
Frank A - 12/11/2020

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