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Mount-n-Lock SafetyStruts Standard RV Bumper Support Brackets - 4" to 4-1/2"

Mount-n-Lock SafetyStruts Standard RV Bumper Support Brackets - 4" to 4-1/2"

Item # MO22FR
Our Price: $74.95
You Save: 13%
Accessories and Parts
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Shipping Weight: 3 lbs
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Beef up your RV bumper and boost your weight capacity to 400 lbs so that you can safely haul your generator and other heavy cargo. Brackets mount to 6" or taller I-beams and S-beams and 4" or taller tube frames to reinforce your bumper. 1-833-496-1390 to order Mount-n-Lock accessories and parts part number MO22FR or order online at Free expert support on all Mount-n-Lock products. Guaranteed Lowest Price and Fastest Shipping for Mount-n-Lock SafetyStruts Standard RV Bumper Support Brackets - 4" to 4-1/2". Accessories and Parts reviews from real customers.
  • All Info
  • Reviews (99)
  • Q & A (0)
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  • Why etrailer?

Mount-n-Lock Accessories and Parts - MO22FR

  • RV Cargo Carrier
  • RV Bumpers
  • Bumper Parts
  • Mount-n-Lock

Beef up your RV bumper and boost your weight capacity to 400 lbs so that you can safely haul your generator and other heavy cargo. Brackets mount to 6" or taller I-beams and S-beams and 4" or taller tube frames to reinforce your bumper.


  • SafetyStruts reinforce your RV bumper so that you can carry generators and other heavy cargo
    • Increases weight capacity to 400 lbs
    • Helps prevent bumper detachment from your RV's frame
  • Brackets mount to welded or bolted I-beam, S-beam, and single channel frames 6" or taller, and tube frames 4" or taller
  • Optional spacer bars can be removed to fit around larger bumpers up to 4-1/2" wide
    • Gives you more space on your frame for proper mounting
  • Power-coated, galvanized steel construction resists rust and corrosion
  • Easy, self-drilling installation - nut driver and hardware included
  • Made in the USA


  • Application: 4" to 4-1/2" RV bumpers
  • Overall dimensions: 7-1/2" wide x 5" tall x 5/16" thick
  • Weight capacity: 400 lbs when evenly distributed
  • Quantity: 2 brackets
  • Limited lifetime warranty

Note: Bumper weight capacities vary by manufacturer. Please be sure to verify the weight capacity of your bumper with the manufacturer prior to loading.

Spacer Bars

Spacer Bars

These all-steel brackets also have optional spacer bars that are in place to allow a nice, snug fit around your standard 4" RV bumper. They can be removed so that the brackets fit around larger bumpers between 4-5/16" and 4-1/2" wide, or if your bumper is bolted to the frame and the bolts interfere with the spacer bar.

Spacer bars Used-Unused

If your RV's frame has less than 3" of mounting space, the spacer bars are the perfect solution to create that extra space to properly mount your SafetyStruts. Simply remove the spacer bar, flip it around, re-locate it to the outer part of your bumper, and secure in place with the included nuts and bolts.

1SSNHD Mount-n-Lock SafetyStruts RV Bumper Brackets - Standard Fit - 4" to 4-1/2"

Installation Details MO22FR Installation instructions

California residents: click here

Customer Satisfaction Score:

Customer Reviews

Mount-n-Lock SafetyStruts Standard RV Bumper Support Brackets - 4" to 4-1/2" - MO22FR

Average Customer Rating:  4.7 out of 5 stars   (99 Customer Reviews)

Beef up your RV bumper and boost your weight capacity to 400 lbs so that you can safely haul your generator and other heavy cargo. Brackets mount to 6" or taller I-beams and S-beams and 4" or taller tube frames to reinforce your bumper.


Perfect for my use. I added a bumper hitch to the back of my trailer for my dirtbike carrier.


Relatively easy to install, after trimming a bit of the I beam out of the way. Flush fit with self drilling screws (drill pilot hole first) should be very secure. Before and after pix for reference. Ready to load cargo tray and camp!


Bought this for added support on my trailer bumpe. Installed spair tire carrier and bike rack. Have gone 4000 + miles so far and had n issues


High quality easy to assemble, I think it's great thank you very much.


They were easy to install. The system appears to work. In addition to the spare tire and bicycle rack, I added a generator box. Everything is holding so far.


They were easy to install and gave us confidence of having a little extra weight capacity on our rear bumper. We carry 2 electric bikes on the back. Great job !!


Easy to install,very good instructions. We haven't had any problems and don't expect any.


They help securely hold Predator 3500 generator on the bumper of my travel trailer.


They fit well, however I would be more comfortable if the removable spacer was closer to the back square of the bumper


These brackets are solid and easy to in stall.


Added insurance for trailer bumper. Only use it for light weight items like camp chairs etc. yet the bouncing car carrier on bumps can greatly increase stress of the bumper


Heavy duty (not wimpy) mount for our RV bumper. Using it for our bike rack. Super sturdy.
Shipping was very timely.


It came fast and worked perfectly.


Took 18 days from order placement to delivery for this "in-stock" item. Got nice customer service people with no solutions other than they were sorry for the delay.


Great fit, easy install.


Great sturdy easy to attach product


Very easy to install. Looks good and will see how it works. My bumper is a tube frame welder to an I beam.


Haven’t installed them yet but I need shims and the ones provided are nowhere near what I need.

You mentioned that you will need shims and the shims that come with the struts will not work for you. I wanted to see if you could explain in more detail what you meant.
-- Etrailer Expert Jenny N - 03/09/2022


Appears to work as designed. Difficulty of install about 3 out of 10.


Works great. I carry my inflatable boat and generator on it.


Haven't installed it yet - but I'm going to get a 2" piece of channel 72" long and put clamp that on the lower edge of the 4" tube and then clamp the supports to it and mount the supports. A little extra support can't hurt.


Great product! Highly recommended.


easy to install, may want to use a bit extension to install the self drilling bolts as to get the correct angle.


etrailer delivery was fast and I was kept informed throughout the shipment process. I will tell you that Customer Service was excellent in doing a price match for me against a competing site that carried the same product.

Here's what you need to know about the install. Forget the self tapping screws and use a 3/4" high speed drill bit. Make sure to keep the bit oiled during drilling. Also you will need a minimum of 1 clamp to hold the brace in place.

I would have rated the product a 5 star, but on my rig there is a L-brace also welded to the bumper. The washers included that are supposed to be shims are not thick enough to fit the bracket firmly against the frame. I had to use some additional washers I already had.

But I have no doubt this will hold the extra spare tire I have added to my travel trailer.


You always provide great service, quick order processing, and a great inventory of stuff to choose from.

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