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  1. Anti-Sway Bars
  2. Roadmaster
  3. Anti-Sway Bar
  4. Rear
  5. 1-1/2 Inch Diameter
  6. Mounting Hardware Included
THIS ITEM IS NOT A FIT FOR
2018 Keystone Alpine Fifth Wheel
Roadmaster

Roadmaster Rear Anti-Sway Bar - 1-1/2" Diameter

Part Number: RM-1209-106SP
In Stock
$835.00
Retail:$928.32
You Save: $93.32
Anti-Sway Bars
Not Confirmed to Fit

2018 Keystone Alpine Fifth Wheel

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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. 1-800-940-8924 to order Roadmaster anti-sway bars part number RM-1209-106SP or order online at etrailer.com. Free expert support on all Roadmaster products. Great prices and Fastest Shipping for Roadmaster Rear Anti-Sway Bar - 1-1/2" Diameter. Anti-Sway Bars reviews from real customers.
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Roadmaster Anti-Sway Bars - RM-1209-106SP

Highlights

  • Custom Fit for Your Vehicle: Tuned to your suspension for better control and stability.
  • Reduces Sway: 1-1/2" 4140 chromoly bar cuts side-to-side motion for a steadier, level ride.
  • Improves Handling: Balances weight transfer for confident turns and quick maneuvers.
  • Handles Crosswinds: Keeps the vehicle stable against gusts, passing traffic, and shifting loads.
  • Less Driver Fatigue: Reduces steering effort so long drives feel smoother and more controlled.
  • Uses Existing Mounts: Bolts to rear axle and chassis with included heavy-gauge hardware.
Made in USA

Features to know about

Better Highway Control: 1-1/2" Rear Bar Cuts Sway and Roll

White-knuckling it when big rigs pass or a gust hits the side? This rear anti-sway bar ties the axle to the frame to balance weight transfer and stop side-to-side rocking. The 1-1/2" diameter bar adds real stiffness, so turns and quick maneuvers feel solid and predictable. You get a level ride, even on uneven pavement or in crosswinds, without fighting constant steering corrections.

Confidence in Corners: 4140 Chromoly Strength

Standard steel can flex too much under load, but this setup uses thick 4140 chromoly for serious torsional stiffness. That alloy is harder and stronger than typical 1020 steel, giving the bar nearly 30 percent better sway resistance. When weight shifts through a curve or during a lane change, the frame stays planted instead of leaning and wandering.

Long-Term Durability: Polyurethane Bushings That Don’t Give Up

Rubber bushings break down fast, especially around oil or road grime. This system swaps them for polyurethane, which holds its shape and shrugs off oil, gasoline, and ozone. Less wear means tighter support and a consistent feel trip after trip. A little lube keeps them moving freely without loosening up the connection between bar and chassis.

Close-up of Roadmaster anti-sway bar polyurethane bushings showing durable design and flexible mounting components.

Straightforward Install: Heavy-Gauge Hardware, No Drilling

Everything you need comes in the box—heavy-gauge mounting hardware, easy-to-follow instructions, and bushing lubricant. The bar bolts to the rear axle and frame using a 5" × 4" U-bolt pattern. No drilling is required, and it’s designed to work around most aftermarket suspension accessories, so you can bolt it on and hit the road.

Roadmaster rear anti-sway bar installed on rear axle, showing heavy-duty steel construction and mounting points for improved vehicle stability.

Balanced Setup: Works with Front Anti-Sway Bar for Maximum Stability

If you ever decide to upgrade both ends, this rear bar pairs perfectly with a front anti-sway bar (sold separately) for an even more planted ride. Together they keep the chassis flat and steady from front to back, cutting sway at the source and making every mile feel easier.

Specs

Dimensions

  • Bar diameter: 1-1/2"

Compatibility

  • Designed for use with: 5" x 4" U-bolt pattern

Warranty

  • Limited lifetime warranty

1209-106SP Road Master Anti-Sway Bar - Rear

Installation Details RM-1209-106SP Installation instructions

This Product Fits The Following Vehicles




Ratings & Reviews

4.8

2526 reviews
5 Stars
(2160)
4 Stars
(252)
3 Stars
(48)
2 Stars
(22)
1 Star
(44)
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by:
2013 dodge Ram Pickup
Great instructions and nice, high quality fasteners.
Fitment was great and only minor adjustments to my Air lift air bags was needed.
I have a 2013 Ram 3500 Dually with:
-Torklift 30K hitch
-5” Exhaust
-Air lift 7500XL air bags.
The lower brackets for the air bags needed to be moved slightly and I had to cut the excess bolt off on the passenger side.
Matthew profile picture

Matthew

10/7/2026

This is a complete game changer when using a truck camper Mine is an Arctic Fox 990. I would list this under a must have accessory when using a truck camper. Unloaded ride when you hit off camber bumps is slightly rougher, but hey its a Ram 3500 dually for hauling heavy stuff. Also the performance when carving twisty canyons with an empty truck is astonishing....Watch out Corvetts, here I come!

Jameson C. profile picture
Etrailer Expert

Jameson C.

10/7/2026

@Matthew great to hear! I am glad it's working well for you!
by:
Excellent high quality product made a big difference in handling with heavy Artic Fox camper
Give poor rating regarding installation instructions
Fred profile picture

Fred

8/15/2026

Excellent it works great

Jerred H. profile picture
Etrailer Expert

Jerred H.

8/16/2026

@Fred That's great to hear Fred! Thanks for coming back and sharing that feedback!
by:
RM-1109-121 Rear Sway bar for 85 Chevyvan G30 RV. Install was pretty straightforward. I would mount the brackets to the frame first and then the sway bar to the axle. It’s easier to drill the holes without the sway bar getting in the way.
Before I replaced the shocks and upgraded the from sway bar and added the rear sway bar my G30 Chevyvan Winnebago was a wallow wagon. It took 110% focus to drive. Now it drives like a regular vehicle. Smooth. No leaning over when cornering. It’s night and day.
Gwendolyn Y. profile picture
Etrailer Expert

Gwendolyn Y.

4/8/2025

No more white knuckling! That's awesome to hear, Kris. I'm glad that this bar helped so much so you can have a more relaxed drive :)

Kris profile picture

Kris

3/17/2026

I have taken a few trips with the Clatter Cabin now. It’s been enjoyable to drive. Since then I have replaced the exhaust from the engine back with 2 12 inch pipe. I was able to get the pre bent exhaust parts over the axle and clear your rear sway bar nicely. Now she purrrrs!

by:
I have carried a truck camper for 7 years with just Timbrin blocks also from Etrailer and finally made the move to Roadmaster anti sway bars front and rear. Planning a trip to the west coast from Georgia next year and wanted all the help I can get for stability on the mountain roads. Have yet to test but Im sure it will be a noticeable improvement. When my wife takes the wheel so I can have a break she would see-saw the steering wheel to balance the load and it drove me insane. Hoping for relief for both of us.
Kate F. profile picture
Etrailer Expert

Kate F.

9/24/2025

Install looks great Steven! I can't wait for you to take it out for a spin so you can see the difference for yourself, it is amazing what a upgraded sway bar does to your ride, no more white knuckles for you, or your wife. What big stops do you have planned on your trip to the West Coast?

by:
2025 Ram 2500
2025 Sprinter 2500 low roof WITH factory sway bar. Added this bar to control the terrible handling at the rear of these vans and it absolutely takes care of that. Be aware that you 100% need the retro-fit kit for this bar to be installed as the factory sway bar end links will NOT work. The retrofit kit that you need is the RM-590064-00.
by:
2007 Ford F-250 Super Duty
Great buying experience with ETrailer. Fast shipping and quality constructed part. Noticeable difference in controlling body sway. Very pleased with the bar and highly recommend Etrailer.
Ken profile picture

Ken

8/19/2025

No complaints with the handling. This is a good sway bar!

by:
After about a year with both the Roadmaster Rear Anti-Sway Bar and the TorkLift StableLoad Upper Overload Spring Upgrade on our truck camper setup, my experience has been mixed.

With the StableLoads, some of the mounting screws eventually fell out. I contacted etrailer expecting the issue to be handled under warranty, but instead of taking care of the replacement directly, I was referred to the manufacturer. Considering the age of the product and that it was purchased through etrailer, I was disappointed with how the warranty issue was handled.

As for the Roadmaster 1-1/2" rear anti-sway bar, it is a very solid and well-built product, but in our particular application I honestly haven't noticed a major difference in body roll while taking turns with the camper loaded. I have driven the truck both with and without it, and the improvement was much less noticeable than I expected.

Neither product is necessarily bad, but based on our experience, the improvement in handling hasn't been significant enough for me to strongly recommend them given the cost.
by:
2012 Ford F-350 Super Duty
I prefer to purchase direct from most manufacturers due to tech support and service. However I find myself purchasing from etrailer.com more and more due to the positive experience, expert tech chat advice, fast shipping and great prices to name just a few. It makes all the difference knowing that you are communicating with a real person and not AI. The Roadmaster 1 3/8” rear sway bar has been my most effective purchase for my truck to date. The SuperSprings SuperSway Stops are right up there in effectiveness as with the rear sway bar. The rear sway bar and SuperSprings SuperSway Stops were very easy to install and I feel like I am driving a different truck. In combination, the two purchases have made the truck and camper feel like one vehicle; no longer does it feel like a truck with something in the bed. VERY stable on turns, twists, hills and angles. I cannot recommend these products enough.
by:
2022 Ford E-Series Cutaway
Received the product in a timely manner. The shipping company used I’d give a no star rating. I received the anti-sway bar bare out of a box or wrapper with the installation part box and a cut out piece of cardboard with the shipping label on it taped to the bare bar with about five yards of packing tape. The bar was scuffed, scratched and chipped with the RoadMaster label destroyed. I realize it’s going to be installed under the front of my motorhome but as much as it costed I would like to be the one to scratch and scuff it. If I was a company installing this on a customers vehicle I’d return it. I do not believe it was shipped from etrailer in this condition.
Jenny N. profile picture
Etrailer Expert

Jenny N.

6/25/2024

What I recommend is touching it up with a rust resistant paint like Rustoleum. We will be in contact with you about the damage. Please keep an eye on your email.

Leonard profile picture

Leonard

6/22/2025

After a year and many miles I would give it a five star for sure. Made a great improvement over the stock anti-sway bar. With the rear and front RoadMaster anti-sway along with the RoadMaster steering stabilizer the E-450 33 foot class C motorhome drives like a dream. I highly recommend these three products. If not all at once then this order, 1st rear anti sway bar then 2nd front and then the steering stabilizer with the spring on it.

by:
The anti sway bar is a big improvement when the truck bed camper is on. The installation took a bit longer than expected because the frame brackets don’t fit around an aftermarket B&W gooseneck hitch. I had to fabricate new top brackets and drill out the bottom brackets to widen the bolt pattern. Keep this in mind if you have a gooseneck hitch.
by:
a quick fix it to install sway bars front and rear.
I did this and just came home from 2400 mile trip.
installed rear only before we left, then at our destination installed front.
the drive back it handles wayyy better and it sits level now.
""your results may very-use at your own risk. ""
from etrailer.com
rear = RoadMaster 1259-109.
front = RoadMaster RM-1259-105 with RM-590063-00 bracket kit.
i'm sure over time they will flex and stress and start to lien again.
But for now it looks much happier. ( and level )
and i'm very happier with performance and drivability
Seems the big bars help distribute the load to both sides,
you can drive it with one hand now.
and when a truck passes, it's very manageable.
( this could be part the tires on it )
these can be installed in about 6 hours pretty easy.
The hardest thing is drilling the 8 holes in frame. ( 4 front 4 rear. )
We had to shift 2 brake lines over via and small bracket and covers lines with old fuel like to act as wear buffer.
Dan K. profile picture

Dan K.

4/22/2026

wondaful! highly recommended.

by:
2022 Ford F-350 Super Duty
After waiting 3 weeks the swaybar kit was drop-shipped from the factory. Received and discovered the bushing inserts were the wrong size (too small) for the bolts that were sent. Contacted Roadmaster support and provided them a photo and invoice as requested. The replacement inserts were approved and shipped out. I got metric bolts to go with the inserts I received. I will save the replacements for additional replacements.
The install was fairly straight forward.
Haven't had a chance to tow the 5th-wheel yet.
by:
The products itself is good. Works well. But you would think when you spend $800 for something, the directions could be very detailed. There could be a complete video of it being installed. They don't give you specs for torquing any of the bolts and some very lousy pictures with a small amount of instruction. You can do better Roadmaster you want to charge me a lot of money for something then give me great detail on in installing it as well.
by:
This is a must have for your Motorhome. What a difference in the ride of the coach through the highway washes, the side winds and the side drift of the big rigs. This bar reduces the coach movement by as much as 80% I would say. The installation is easy for someone who is mechanically inclined and still doable for DYIer as long as you have the tools ( standard 1/2” drive tool set, low speed high torque drill for the holes in the frame and a 250 plus ftlbs torque wrench). I would highly recommend this Anti-Sway Bar.
Gwendolyn Y. profile picture
Etrailer Expert

Gwendolyn Y.

4/28/2025

High-five on the install, Curtis! Also, thanks for sharing all the pictures and showing all the angles of the sway bar. They are really helpful for anyone looking to tackle this install themselves at home!

by:
dodge Ram Pickup
I Installed the bar in my Ram promaster HR 2500 and it’s an incredible difference on twisty mountain roads. I highly recommend it.
by:
2019 Forest River Georgetown 5 Series GT5 Motorhome
you guys did great package was damage RM-1139-149

Roadmaster Rear Anti-Sway Bar - 1-5/8" Diameter the sway bar itself
by:
2026 Ford Transit Connect
Super quality product build. However it is made for ford transit dually. I have single rear tires. Worked with road master rep to select the correct sway bar for my van.. RM82EQ
by:
Grate stuff. Easy to bolt up and figure out. Drive quality improved dramatically and less sway with trailers.
Just in the kit with the grease and red lock tight the hardware washers were one size to large so I got the right ones and installed all is well.
Brooke M. profile picture
Etrailer Expert

Brooke M.

6/17/2025

So glad to hear that, Dimitrios! Thanks for including a photo, too.

by:
Easy installation ,done by myself laying on my back in the driveway only took about 1 1/2 hours to do. I have a lift but didn't use it and I think it was easier on the ground for just one person. Sway bar made a big difference in the drivability of my 2003 E350 pleasure way class B
I'll upgrade the front factory bar to the HD Roadmaster bar soon
If you have issues with the handling of your Ford pleasure way start with this sway bar
by:
After a year of usage, I couldn't be happier with the Roadmaster front and rear anti-sway bar kits. The rear kit for my W22 chassy, the mounting hardward would not fit properly. I call Roadmaster directly and they custom built the mounts, painted, and shipped within days.
Michael profile picture

Michael

3/25/2026

After a year the system is working great. It has made the driving much safer and smoother.

Gwendolyn Y. profile picture
Etrailer Expert

Gwendolyn Y.

3/25/2026

@Michael Love hearing about your yearly updates, Michael. Where are you headed to next?
by:
I have a hard side slide in camper in the back of my pickup. This is the first time I installed an Anti-Sway Bar of any kind. It took me about 6 hours to install. But it works, and it works really well. I'm glad I took the time to install it.
by:
Ford F-350 Super Duty
I love this sway bar, and love the service and overall experience with etrailer. My F350 came with factory sway bars front and rear, and I'd replaced the rear bar several years ago, and was impressed with the difference it made. So, more recently I ordered the front bar to replace the smaller factory unit, and it again made a wonderful change for the better. Our Bigfoot truck camper is tall and heavy, but our rig handles wonderfully and has essentially no sway or rock in traffic or on bumpy roads. I highly recommend this sway bar.
Gwendolyn Y. profile picture
Etrailer Expert

Gwendolyn Y.

3/7/2025

Sounds like a much smoother drive, Riley! I looked up your camper to see how tall it is and I can see exactly why its called a Bigfoot. What's been your favorite place you've traveled to so far with the camper?

Riley profile picture

Riley

3/6/2026

The two Roadmastercsway bars weve been using continue to impress and perform like they did on day one. Driving back across the country with some days having stiff criswinds continually we rode comfortably and never had handling or steering issues. I remain adamant that these are undoubtedly the best products on the market for this application and welcome any questions. For reference my truck is a 2018 F350 crew cab DRW, 6.7 diesel 4x4 long bed with Bigfoot 3000 series truck camper. Get the Roadmasters!

by:
2017 Chevrolet Express Van
Easy to install by myself in the driveway. I replaced both the front and rear anti-sway bars and the improved handling characteristics were noticeable immediately. Fantastic product!
by:
As others have said the sway bar is good but the directions could be improved. Removing the old down link on the drivers side is a bit of a challenge as you can't easily remove the old bracket until you remove the downlink. Unfortunately you can't get the bolt holding the link to the bracket without supporting the fuel tank and removing the rear strap so that you can push the tank over far enough to get the bolt out. Another issue was the old U brackets holding up the old sway bar were on 3" centers where the new bracket is on 2 3/4" centers. This looks like an insurmountable problem until you remove the star washers holding the old bolts where you can see there is a slot which allows you to use the bolts included. The old bolts were both attached to a plate which kept made the center distance between the bolts non adjustable so using the old bolts is not an option. On the passenger side the plate holding the 2 bolts was connected to the axle connection for the height sensing proportioning valve. I removed the 3 bolts holding it, took out the plate and cut off the front most bolt and reinstalled the plate. Fortunately that allowed me to use the old bolt in the plate and for the front most bolt I used one from the kit and achieved the 2 3/4" center spacing needed for the new bracket. All of this would be nice to know when you tackle this job. Fortunately I had all the tools needed to complete the job. I found it easy to install the new bar despite its weight by lifting up one end of the sway bar and loosely attaching it to the the down link. I then did the other side and once both ends were attached I put the center of the bar on my hydraulic jack and lifted it into place. This made it a fairly easy job to position and attach the U brackets to the axle despite the heavy weight of the bar. A video of this process on an older (1998 vintage) Dodge Ram 2500 would be a big help.
by:
2018 Ford F-53
Installation was 6/10 in difficulty only because of obstacles in the way of the top bolt on the passenger side end link. This was a step up to a 1 3/4" bar from the factory 1 1/2" bar. The end links were much beefier than the factory ones.
Initial test drive - I was impressed that the front roll on curvy roads was greatly decreased. This has been a significant improvement to driveability.
Brooke M. profile picture
Etrailer Expert

Brooke M.

6/18/2025

Super happy to hear that, Kevin! Thanks for including the photos, too. Would you have any tips or tricks for any future readers about how to get around the obstacle you mentioned?

Kevin B. profile picture

Kevin B.

6/21/2025

@BrookeM The air conditioner compressor, hoses, and hardlines were the obstacles. I may have saved some time and effort if if I had a right angle impact tool or maybe a wobble extension with a more compact impact gun, or even a fine tooth rachet. I was turning the upper endlink bolt one click at a time. My advice for any project, that I failed to follow this time... :(, is to dry run through the install to make sure you have what you need to do the job. You may have the right size sockets and wrenches but do they fit and effectively work in the space they need to? It's worth 10 or 15 minutes to do so and usually results in some new tools in your tool chest that you'll be thankful for on future projects.
Brooke M. profile picture
Etrailer Expert

Brooke M.

6/22/2025

@KevinB That is sound advice, for sure, Kevin! Sorry to hear about the delay but I appreciate you talking about what would have saved you some time and hopefully your tips here will help someone else out, too :)
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See what our Experts say about this Roadmaster Anti-Sway Bars

  • Anti-Sway Bar and Steering Stabilizer for a 2012 Freightliner M2
    We have different sway bar options depending on how your 2012 Freightlinter M2 is equipped. The sway bars for this vehicle will fit 2 different Class A motor home models and 3 different EV Type 1 vehicles (emergency vehicles). Starting with Class A models, if it has an 8,000 pound rear axle you would use # RM-1209-116 but it won't fit if the vehicle has the auxiliary cooling package. If the vehicle is an EV Type 1 with airliner air suspension with chains and 5 x 4 u-bolt pattern you would...
    view full answer...
  • Roadmaster Rear Ant-Sway Bar for Freightliner
    If you're looking to order four of the Roadmaster Rear Anti-Sway Bar, part # RM-1209-106SP, you just need to "4" into the Quantity box. The anti-sway bar is confirmed to fit the Freightliner FL-Series from 1991 to 2012 and the Freightliner M2 with Airliner suspension from 2003 to 2017.
    view full answer...

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