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U-Bolt Kit for Mounting 5,200-lb to 7,000-lb, Round Trailer Axles - 7-1/16" Long U-Bolts

U-Bolt Kit for Mounting 5,200-lb to 7,000-lb, Round Trailer Axles - 7-1/16" Long U-Bolts

Item # APUBR-9
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Mount your round, 3" diameter axle to your trailer's leaf springs with this U-bolt kit. U-bolts, plates and nuts included. Great Prices for the best trailer suspension parts from Redline. U-Bolt Kit for Mounting 5,200-lb to 7,000-lb, Round Trailer Axles - 7-1/16" Long U-Bolts part number APUBR-9 can be ordered online at or call 1-800-940-8924 for expert service.
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  • Reviews (286)
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  • Videos (2)
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Redline Trailer Suspension Parts - APUBR-9

  • U-Bolt Kits
  • Camper
  • Car Hauler
  • Utility Trailer
  • Round Axle - 3 Inch
  • 7-1/16 Inch Long
  • 5200 lbs - 7000 lbs
  • 9/16 Inch Diameter
  • Redline

Mount your round, 3" diameter axle to your trailer's leaf springs with this U-bolt kit. U-bolts, plates and nuts included.


  • Attaches trailer axle to leaf springs
  • Includes:
    • (4) 7-1/16" Long U-bolts (176500)
    • (2) U-Bolt plates for 1-3/4" or 2" springs (117521)
    • (8) 9/16"-18 Hex nuts (916N)
  • Spring seats required for mounting axle to leaf spring sold separately


  • Axle diameter: 3"
    • Typical 5,200-lb to 7,000-lb axle
  • Spring width: 1-3/4" or 2"
  • Dimensions: see below

U-Bolt Diagram

APUBR-9 U-Bolt Kit for 5,200-lb to 7,000-lb Round Trailer Axles

Video of U-Bolt Kit for Mounting 5,200-lb to 7,000-lb, Round Trailer Axles - 7-1/16" Long U-Bolts

Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.

Video Transcript for Redline Trailer Suspension - Leaf Spring Suspension - APUBR-9 Review

Today we'll be reviewing Part Number APUBR-9. This is Red Line U-Bolt Kit for mounting 5200 lbs to 7000 lbs round trailer axles. It's going to attach the trailer axle to your leaf springs, it's going to include four 7 1/4 U-bolts, 2 U-bolt plates for 1 3/4 inch or 2 inch springs, and then it's going to include eight 9/16 inch hex nuts. Spring seats are required for mounting the axle to the leaf springs and that's all going to be sold separately. It's going to fix axle diameters of 3 inches, typically 5200 lb to 7000 lb trailer axles. The spring width that this would fit is going to be 1 3/4 inch or 2 inch and we'll just take a few moments to go over some dimensions. We take a measurement of the length of the u-bolt, again we're measuring from the bottom of the cross member, to the base of the bolt post.

It's going to give us a measurement of 7 1/4. The threaded portion on each bolt is going to measure 3 inches. It's that portion there and then the width that we have in between is going to measure right at 3 inches and that's just a measurement between the bolt posts. Taking a look at one of the plates, it's going to measure 5 1/4 by 3 3/4. We measure the distance, center on center between the holes going this direction, it's going to measure 3 3/4 of an inch and then center on center going this direction is going to give us a measurement of 2 5/8 of an inch. That's going to do it for our look at Part Number APUBR-9, this is Red Line U-Bolt Kit for mounting round trailer axles and again the bolts are going to measure 7 1/4 of an inch in length.


Customer Satisfaction Score:

Customer Reviews

U-Bolt Kit for Mounting 5,200-lb to 7,000-lb, Round Trailer Axles - 7-1/16" Long U-Bolts - APUBR-9

Average Customer Rating:  4.7 out of 5 stars   (286 Customer Reviews)

Mount your round, 3" diameter axle to your trailer's leaf springs with this U-bolt kit. U-bolts, plates and nuts included.


Ordered a lot of parts for a dump trailer rebuild in Sept. Didn't install some of the final parts until Christmas break. THEY SENT COARSE THREAD NUTS INSTEAD OF FINE. I ruined 2 u-bolts and need all 16 fine thread nuts. I'm outside 60 days so I was told I'm on my own. I've spent $5k+ on etrailer. I'll find some place else.......

Etrailer Expert

Brooke M.


Hmmm...I dont like this either. I am going to send this to a customer service team lead to see what we can do. I am sure they will have a better solution for you! Hang tight!


U-Bolts and hardware seem to be good quality. Package was delivered when promised. Very satisfied with purchase. Will be buying from E-Trailer again.

Robert T.


They are working great. No problems or issues with them.


Exact replacement for original parts, easy install


Axels are a perfect fit for my trailer and are working great.


Everything arrived quickly and as descr ibed.



Put the suspension kit on my dump trailer about a year ago and has held up very well.

Etrailer Expert

Jerred H.


@Michael Happy to hear that! Thanks for the feedback!


3 weeks late box was completely destroyed and missing bokts

Etrailer Expert

Brooke M.


Gosh that is frustrating, I am so sorry! I will make sure our customer service team reaches out to you about this.


The ladies at etrailer are awesome! Unbolts work on the new leaf springs , they know there products. I will buy from them for all my projects!
Thank you


Great product haven’t had any problems yet ands it’s been about a year


Excellent Help.


I chose this particular kit mainly for the 9/16" u-bolts. I could have easily used the 1/2" kit but it was a nice upgrade and not much difference in cost. These u-bolts and plates fit my car trailer perfectly without any modifications. Everything in product description was just what it said when I received them. Shipping was faster than I expected!


What I ordered. Got to me quickly.


I had rusted old bolts and leaf springs, these were great replacements. No issues look great work well and fast shipping.


Delivered as promised and installed as required.
No problems with service and the product.
Excellent company to do business with. Always glad to have etrailer available for go to supplies at lowest cost.


Excellent parts for the project I was working on. I installed a 1997 Chevy axle on a 1950 International box trailer. With a few “adjustments”, I made it work!


Very wonderful and knowledgeable about parts and got parts ordered and paid for and received them very quickly , very happy this place is open on sundays and will use this company again!! Again thank you !!!


As described


Ordered new leaf springs for 2020 Grand Design 303RLS. Replaced OEM 4 leaf spring with 5 leaf spring. Perfect fit.


I finished installing my new springs on my trailer today. Every thing went together without any problem.i am very pleased with your product.


Customer service went above and beyond, had a problem with a bolt missing and they shipped one to me no problems.



Working Great!


Replaced the 4 leaf leaf springs on my 5th wheel with the 5 leaf leaf springs and the mounting kit, so far it seems to have solved the problem of the springs breaking. The trailer handles better then ever on the highway and the back roads. Couldn't be happier.

Robert S.


Couldnt be happier with the mounting kit and etrailer


Got what i was looking for and got great input from Customer Assistance.


The parts arrived quickly and were an exact fit, thank you!


The products from etrailer are great quality and received on time and have been very reliable


Arrived as advertised. I would have liked to have locking washers or any kind of washer for that matter! That would be an opportunity for improvement. Otherwise very good product.


After 30 years and many miles of towing, my trailer suspension finally succumbed to the ravages of Michigan roads and the salt used on them. I replaced the original single leaf spring suspension with a new multi-leaf system from and couldn't be happier with the results. The trailer tows much nicer now and with everything new and tight my tires are wearing at a much slower pace. I have since ordered a hitch coupler rebuild kit from which installed easily and is working very well. I wouldn't hesitate to recommend to anyone.

Show More Reviews

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  • Dimensions of U-Bolt Kit for Mounting 5,200-lb to 7,000-lb # APUBR
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