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The Roadmaster Rear Anti-Sway Bar uses a thick 1-1/2" diameter 4140 chromoly steel bar that ties the rear axle to the chassis to balance weight transfer in corners. The high-strength chromoly alloy resists flexing far better than standard 1020 steel, cutting body roll and rear-end sway when cornering or changing lanes. The result is a more planted, predictable feel with noticeably less lean and side-to-side motion.
Crosswinds and passing semis no longer have to demand constant steering correction. By anchoring the rear axle to the frame, this bar steadies the chassis so it stays level even when road or wind loads shift suddenly. The improvement in stability means you can hold a straight track with less effort and feel more in control on long highway stretches or uneven surfaces.
Instead of soft rubber, this system uses polyurethane bushings that stand up to oil, gas, and ozone. They hold their shape under heavy loads, so the bar’s response stays consistent over time. Less flex in the bushings means better support and a more direct connection between chassis and axle for every mile down the road.
Installation is straightforward with no drilling required. The kit comes complete with heavy-gauge mounting hardware, bushing lubricant, and clear instructions. It retains the factory sway bar and bolts directly to the axle and frame, making it easy to add serious stability without permanent modifications.
Engineered for years of service, the 1-1/2" chromoly construction and fixed end-link design combine to create a system that resists wear and keeps handling tight. It’s backed by a limited lifetime warranty for added peace of mind.
Customer Satisfaction Score:
74% were satisfied with this product
26% of customers were not satisfied
Ratings & Reviews
Very happy with this product. Greatly reduced the side to side sway of my 40 foot made it much easier to drive and improved handling. Installation was done by me and was not difficult at all, anyone with good basic mechanical skills can handle the install.
I received and installed the rear anti-sway bar ahead of schedule. No problem with the install. I also installed the front replacement anti-sway bar. I have not driven the coach to see what difference it makes but replacing the small front anti-sway bar and adding the rear anti-sway bar has to improve the handling.
Ordered Sumo springs and steering stabilizer for our 2018 FR3. The service was outstanding. And the shipping was expediant. Couldn’t have been a more agreeable experience other than paying for it. Lots of laughs.
I live in the same town as the Road Master factory, so I stopped by to see what I needed for my 2006 HR motorhome.
Then I went home to order from E-Trailer to save almost $400 below the factory prices on the two sway bars. Yes I'm very happy with E-Trailer!
The addition of this auxiliary rear sway bar noticeably improved the handling of our Newmar Baystar. It was well worth the investment.
Installed the Roadmaster anti-sway bar on my 2017 Thor Miramar 34.1 today. The installation was relatively simple. What a difference! The pitching and leaning of my coach was dramatically improved. Money well spent!
This is in response to installing my anti-sway bar. While checking out the procedure for installing my Road Master anti-sway bar, I found out why I needed one, the original anti-sway bar "U" clamp was broken rendering the original sway bar useless. After repairing the original sway bar, myself and my neighbor which is a mechanic began installing the new anti-sway bar. First of all, you will definitely need an IMPACT WRENCH to remove the four bolts on the frame to install the mounting brackets. These bolts were put on with an impact wrench and put there to stay. After installing the mounting brackets everything else went smooth. Two people will be needed to install the large sway bar due to the weight of the bar. Now I have two sway bars, the original equipment and the Road Master. As far as how the equipment will work I will let you know as I will be leaving the 19th September for a month-long trip through AL, MS, LA, Texas, New Mexico, AZ, Okla, MO, AR, then back to FL.
Promptly shipped. Correct item. etrailer did good.
Road Master however packaged the parts for the sway bar poorly. In particular, they put a little cup of the grease for the bushings in a bag along with large bolts/nuts/washers without a lid. The grease got everywhere. This is not an etrailer issue obviously, but this is the 2nd time in 2 weeks I saw Road Master mess up on their packaging (the 1st time, the entire box with the sway bar mounting hardware was missing). Road Master needs to have better outgoing Quality Control.
I just spent several hours trying to install RM1139-145 only to find that I have again ordered the wrong item. Now I can not return the item this time because I do not have the original carton the item came in. The box went out with the trash before I got to start the install procedure.
Oh well, just several hundred dollars wasted.... We will just eat light and cancel a few camping trips for a couple months...
We will survive without the Anti-Sway Bars while the camper is parked in the driveway.
Rear sway bar made a big difference in body lean and roll. Motorhome is much more stable.. I also added Sumo springs on all corners. I put sway bar on first and it made a big difference.
Well worth the money. I installed aftermarket front and rear ant-sway bars on my FR32. Great support from emailed as well in the selection process. They actually answer the phone and take the time to walk you through the process. The reason I am taking the time to write this review is directly because of their 1 year follow up email. Kudos etrailer!
Great product. Fairly easy to install. Instant results in the driving quality of the coach.
Once again e-Trailer exceeds our expectations! Their customer support is top notch! Kyle was very helpful with our order and followed up with an email to also advise us our delivery was made today along with helpful videos.
We can’t wait to get front & rear sway bars installed on our Class A Motorhome!
The anti sway bar helped a lot, but my Fleetwood could use a little more help. Probably needs the front end too. I installed the model made for coaches a year or two newer and it went on much easier than the unit requiring frame drilling and coil spring recounting. I ordered both to cover myself, didn't open the kit for older chassis and sent it back - for full credit, except for shipping, which is fair. Trailer met each promise - product, dates, and return of the unused unit. 5 stars for service 3 stars for eliminating the sway. ETrailer provided EXCELLENT videos for installation, and did everything they said they would! My wife is happy and I'm her hero. That's always worth 5 stars!
very happy with the product and with Etrailer. Anyone who owns one of these motorhomes realizes it's a step by step process to get it have decent ride characteristics, and adding sway bars and trac bars and steering stabilizers are all part of it in a step by step process. Every little bit helps!
Greg S.
4/13/2022
Its all good, its still like driving a saltine box down the road, but it has definite improvement over stock configuration of the f53
I spoke with Jameson, he understood my issues and recommended 2 stabilizer bars. They were delived on a tight time-frame. These ba4s made all the difference in the handling of my Newmar Baystar Sport. THANK YOU FOR YOUR EXPERTISE!!
Heather A.
4/10/2025
Awe, I am glad Jameson was able to get you what you needed Brenda. I posted this review in our team chat for him to see. Where are you taking the Newmar next? That's one heck of a motorhome.
Delivery was fast and great.Paula S is a very excellent person to have working for your business She was very helpful in helping me out getting the right parts and fun to talk to. Thanks again for your help.
I have a 2015, 32 foot RV and this auxiliary sway bar completely changed the way my class A RV drove. The first suspension upgrade I made was a steering stabilizer, which helped a little bit but I was still wandering all over the road. After installing this I can confidently say this should have been my first upgrade. The rear end is now planted, when passing or being passed, and this has made driving long distances a breeze. I know it’s not cheap, but it is totally worth it.
Very well constructed fit and finish are top of the line. I have not tried this yet because I need a 21mm crows foot wrench for my torque wrench(200 ft-lb) for the cross tube bolts.
I am hoping that it will minimize fishtailing from our tow car, as well as controlling sway.
I put both sway brs on today with help from my friend. They went just
as the paper work said, except for the front. You only replaced two of the bolts holding on the bushing brackets. We just reused two of them. Everything seemed to work great on our test drive. I just took
a picture of the front sway bar because the rock guard was in the way of a decent pic. Everthing went great.
Winnebago vista. This was easy to install. The additional sway control in the rear is the most noticeable of the three improvements I did. They weren't the lowest price I could find. But they did have all three items. The shipping was quick. The installation videos were very helpful. I used my leveling jacks to assist in installing the frame brackets.
I thank Cathy T great help she gave me.
I installed the front and back anti sway bars on my 2016 George Town Motorhome. It has the ford f-53 chassis and a Dana 150 rear end. I use road master RM-1139-145 on the rear and
RM-1139-140 on the front. Thanks to Cathy T she set me up with the right parts.
I don't have any more body roll and the 18 wheelers bearly push me over now. If not at all. I also have the road master reflex steering stabilizer Rm-BK9-RSSA.
This part was absolutely the right pick. I researched a lot of anti-sway products and this one came out on top due to its simple installation (thanks to the etrailer video), price and support from etrailer. It went on just like the video showed, though I had to use an impact wrench for the chassis bolts, the etrailer guy who used a wrench must be a beast. Definitely a DIY project even for novice mechanics. I test drove it and it was hands down the biggest improvement in ride even though I had put on new shocks and have air bags. etrailer is my go-to for nearly everything I do to my RV.
I think the anti-sway bar is the most noticeable. When I'm turning out of my driveway where there is a dip as I go over the curb-cut, for example, the sway seems limited moreso than before. As for the steering stabilizer, I think the RV seems a little harder to turn at a slow speed, but I don't notice a lot of difference in it's "springing back to straight" as I'm going down the highway. Some of that may be due to the crown of the road. I'm anxious to try it on the interstate to see if it is better there.
Well, I drove on a smooth, level Interstate with a tailwind, and it handled like a dream.
Bottom line, the biggest difference in driving is the wind and the road surface. These components probably help a little, but I'm not sure it was worth the cost. I'd like to think the RV handles a little better, but I'm not sure that isn't because I want it to after spending the $$$ for these upgrades.
While not the transcendent experience some of the other users had, this did make a noticeable difference. My star rating represents a product doing exactly what it was supposed / advertised to do.
I was told the rear anti sway-bar would eliminate 65% of the movement. And that is an accurate description of the improvement. It was most noticeable on uneven roads and highway ramps. When the coach would have rolled 3-4 times, it's now 1 time. And, on long sustained curves the degree of roll is less.
I paid to have it installed. After looking at it installed, it would have been easy to do on my own.
I recommend the anti sway-bar for anyone looking to reduce body roll.
Condition: Installed
Notes: Item has been previously test fit and has minor cosmetic install marks.
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Randy P.
12/7/2022
Whow! What a great product! Makes driving our class a Motorhome so much more enjoyable,