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

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

Item # MO34VR
Our Price: $84.95
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Beef up your RV bumper and boost your weight capacity to 400 lbs to safely haul your generator and other heavy cargo. Universal design mounts to most RV frames to reinforce your bumper and prevent metal fatigue that causes your bumper to detach. 1-800-940-8924 to order Mount-n-Lock accessories and parts part number MO34VR or order online at Free expert support on all Mount-n-Lock products. Great prices and Fastest Shipping for Mount-n-Lock SafetyStruts Universal RV Bumper Support Brackets - 4" to 4-1/2". Accessories and Parts reviews from real customers.
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Mount-n-Lock Accessories and Parts - MO34VR

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

Beef up your RV bumper and boost your weight capacity to 400 lbs to safely haul your generator and other heavy cargo. Universal design mounts to most RV frames to reinforce your bumper and prevent metal fatigue that causes your bumper to detach.


  • 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
    • Included standoff spacers are required for welded or bolted I-beam frames shorter than 6" or any size double channel frames
  • 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
  • Installation requires some drilling - drill bits and mounting 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.

Universal Application

Universal Application-Standoff Spacers

The included standoff spacers give you the flexibility to mount your SafetyStruts to most RV frames, making it nearly universal. This heavy-duty extension hardware is required for welded or bolted I-beam frames less than 6" tall and any size double channel frames where flanges stick out past your mounting surface. They also combat bolted-frame designs where bolts may obstruct your mounting surface. The standoff spacers won't be necessary if you have a welded or bolted I-beam, S-beam, or single channel frame 6" or taller without flanges, or a tube frame 4" or taller.

SafetyStruts w-w-o Space bar

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.

1SNUHD Mount-n-Lock SafetyStruts RV Bumper Brackets - Universal Fit - 4" to 4-1/2"

Installation Details MO34VR Installation instructions

Customer Satisfaction Score:

Customer Reviews

Mount-n-Lock SafetyStruts Universal RV Bumper Support Brackets - 4" to 4-1/2" - MO34VR

Average Customer Rating:  4.7 out of 5 stars   (177 Customer Reviews)

Beef up your RV bumper and boost your weight capacity to 400 lbs to safely haul your generator and other heavy cargo. Universal design mounts to most RV frames to reinforce your bumper and prevent metal fatigue that causes your bumper to detach.


Well made, the kit includes the proper drill bits you need. Not really sure how much these add to capacity and I managed to crush the bumper a bit with a bolt on hitch and a Thule 5 bike carrier. Live and Learn !!


Put theses on because I have a bumper mounted hitch to haul a cargo carrier. I think they definitely will help out in the long run


after installing the brackets, I wasn't worrying the bumper and bikes wouldn't be with me when arriving at campground


JUST what I needed. It helps the bumper supporting a generator and rack that we haul with our 5th wheel.


Purchased Item #MO34VR support struts. The kit comes with everything you need to install no matter your frame configuration, including 2 drill bits. That product did work out nicely and is a HUGE peace of mind product, totally worth the work and the price. I have a 24' Jayco Jayflight SLX with a 4" square bumper. After drilling through the frame I can assure you you'll need the struts if you're utilizing the GennyGo tray to carry a generator. Yes the bumper joints are welded solid but the metal is not nearly as thick as it may appear. Thinking "this is gonna take all day", a few seconds after starting the drill on the frame, I was through the other side. Buy the struts if you have a comparable rig. I know now why they make this product.


we have hauled 2 heavy ebikes on a bumper bike rack on travel trailer bumper
FL to CO
This product gives me piece of mind

It was kinda tough to drill through frame of rv but install was straight forward


Shipped fast...very good quality...very easy to install both items...pleased with purchase...will continue to deal with etrailer


Will see how these work long term. A bit of work drilling into the frame but I think they will hold the tray and generator without stress


Purchased my second bumper support bracket and I’m very pleased with my choice. I appreciate the product and fast delivery from E Trailer


Don't waste your time or money on this. Now my bumper welds are cracked. If you want to carry more than spare tire on rear of camper bumper install a hitch on frame.

Etrailer Expert

David B.


This is not a common thing to happen, can you elaborate on the size of the bumper and age of the unit?


I like the product, however the kit arrived with 2 missing locking nuts that were needed to tighten the bracket to the bumper.

Etrailer Expert

Brooke M.


Thanks for letting us know about this. I have already sent your information to our customer service team and they will be reaching out to you soon.


Quality and theory of the product is great but on my application it didn't work very good. I think for most applications it probably would work as intended.


Just opened the bumper support bracket. Seems to be heavy duty and looks like it’s going to do what I’m looking for. Thank you E Trailer for outstanding product.


Being just only 1 yr old it has rusted an awful lot already. The paint should have been done better. Maybe better QC


I installed these because I was concerned about the stress that would placed on the trailer bumper from the spare tire rack and new Kayak verti rack. Installation was easy and since we have driven over 3000 miles across interstate 40 (alot of bad highway) and the bumper showed no signs of stress cracking at the welds. It was a simple addition that required no welding and the bolts that hold the bracket never loosened. I highly recommend this product, it gives you peace of mind and prevents your gear from snapping off down the road.


I have not had an opportunity to install the safety struts yet. It looks like it's doable with the parts provided.


Thank you so much for your help


Still need to install. Like having extra support for 4” square bumper that cargo carrier attaches to.


Not the easiest to install but it just had to do with the design of my Sunseeker, in most cases it looks a lot easier. Can’t really knock it for that, it’s job was to reinforce bumper. I put a rack with two 40 lb propane tanks on mine so I needed something I knew would not fail, lest I find myself in prison for being negligent and blood on my hands . Worked like a charm, too bad I didn’t think of earlier as it allowed me to carry ample propane for full timing in colder climates. Rock solid is the important part, they work exactly as described.


Good fit, easy to install product as de scribed


Easy install and great design!


Added the extra support we needed to our 5th wheel bumper to be able to haul our e-bikes.


Etrailer is an awesome business. They get right on your order and keep you updated. The brackets seem to be of good quality and well packed. They literally come with everything, even drill bits. I would recommend!


You're my go to fory rv and trailer needs thanks.


Parts were in stockband cheaper than on Amazon.

Show More Reviews

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