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  6. 7 Inch Long
U-Bolt Kit for Mounting 5,200-lb to 7,000-lb, Round Trailer Axles - 7" Long U-Bolts

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

Item # APUBR-8
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Trailer Leaf Spring Suspension
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Redline Axle Mounting Hardware - APUBR-8
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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. Lowest Prices for the best trailer leaf spring suspension from Redline. U-Bolt Kit for Mounting 5,200-lb to 7,000-lb, Round Trailer Axles - 7" Long U-Bolts part number APUBR-8 can be ordered online at etrailer.com or call 1-833-496-1390 for expert service.
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Redline Trailer Leaf Spring Suspension - APUBR-8

  • U-Bolt Kits
  • Axle Mounting Hardware
  • Round Axle - 3 Inch
  • 7 Inch Long
  • 5200 lbs - 7000 lbs
  • 1/2 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.


Features:

  • Attaches trailer axle to leaf springs
  • Includes:
    • (4) 7" Long U-bolts (1755892)
    • (2) U-Bolt plates for 1-3/4" or 2" springs (117521)
    • (8) 1/2"-20 Hex nuts (12N)
  • Spring seats required for mounting axle to leaf spring sold separately


Specs:

  • Axle diameter: 3"
    • Typical 5,200-lb to 7,000-lb axle
  • Spring width: 1-3/4" or 2"
  • Thread dimensions: 2" long x 1/2"-20
  • Dimensions: see below


U-Bolt Diagram



APUBR-8 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" 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-8 Review

Today we're going to be reviewing part number APUBR-8. This is Redline's U-Bolt Kit for mounting 5,200-pound to 7,000-pound round trailer axles. It's going to attach the trailer to the leaf springs. It's going to include four 7-inch-long U-bolts. We get that measurement by measuring from the bottom of the cross member to the bottom of the U-bolt post. The threaded portion is going to measure 1 and 7/8ths of an inch.

Each bolt is going to give us a diameter of a half-inch. The distance that we have between the two posts is going to measure 3 inches. Each U-bolt is going to be identical, so they're all going to offer the same measurements. It's also going to come with two U-bolt plates for 1 and 3/4-inch or 2-inch springs. The overall dimensions of one of these plates is going to measure 5 and 3/8ths of an inch by 3 and 3/4 and again, both of those plates are going to be identical, and then it's going to come with the eight half-inch hex nuts that are needed to secure everything. Spring seats are required for mounting the axle to the leaf spring and those are going to be sold separately. This is designed to fit axle diameters of 3 inches, which is going to be your typical 5,200-pound to 7,000-pound trailer axle, with a spring width of 1 and 3/4-inch or 2-inch. That's going to do it for today's review of part number APUBR-8.

This is Redline's U-Bolt Kit for mounting 5,200-pound to 7,000-pound round trailer axles. .


Customer Reviews

U-Bolt Kit for Mounting 5,200-lb to 7,000-lb, Round Trailer Axles - 7" Long U-Bolts - APUBR-8

Average Customer Rating:  4.8 out of 5 stars   (238 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.

by:

These seem to be working ok but do not appear to be designed for use with the HD upgraded Moryde greaseable shackle kit that I purchased with them . You can see in the photos that they rub and bind


Comments
I do have two recommendations for you. The first would be to make sure that the bolts are not over tightened. The locknuts should only be tight enough to limit as much movement as possible without binding anything up. The second recommendation is that Lippert makes that can be used with the Equa-Flex system. It is part # LC64FR
Lippert Tandem Axle Equa-Flex AP Kit - Wet Bolts - 3-1/8" Long Shackles
$151.39
. The shackle straps are less thick at 0.212 thickness however they are longer at 3 and one quarter inches.
-- Etrailer Expert Jenny N - 04/22/2022


by:

I think you screwed up. I did not receive the U bolt kit, I received Part # CT-3000-RK, Repair kit for 2" straight coupler which I did not order. I reported this upon delivery of the wrong part.


Comments
We recently sent you a new u bolt kit and were wondering if you had any feedback about the product for other shoppers? We look forward to hearing from you.
-- Etrailer Expert Jenny N - 07/21/2022


by:

I used these on my M101A2 military trailer after doing axle swap. They work perfect.




by:

Excellent product, I used it to beef up the suspension on my welding trailer. It has proven to be a great quality product. Even though local stores carry this kit, I trust a company with the word trailer in its name, and for good reason. I recommend your website to all of my welding students, so if you're ever in the mood to send parts for me to install, test, and review. Please keep me in mind. I'm currently searching for a good 10" electric brake assembly to replace my existing set, and I'm sure I will be reaching out to etrailer for their expertise.




by:

Wow! I have ordered from etrailer for years. Great products. I ordered this on a Tuesday and received it Thursday and shipping was Free!
Painting them now to match trailer and installing them tomorrow. All within a week. Like I said, Wow!




by:

these u bolts and brackets arrived quickly, installed flawlessly, and seemed to be heavy duty.
i couldn't be happier.




by:

I pull a toy-hauler 5th wheel trailer between Alaska and the lower 48 through Canada twice a year. Much of the road is rough and caused me to break a leaf spring every trip. Since installing a shock absorber system and upgrading from 5-leaf to 6-leaf springs, I have so far eliminated suspension damages on the route.




by:

The u-bolts fit and worked perfectly. I didn’t use the included tie plates, my travel trailer has shock absorbers that attach to the tie plates, I reused the originals. I torqued them to 70 ft. lbs. per Dexter axle specifications. I did clean and paint them before installing. I upgraded my 5400 lb. 4-leaf springs to 6000 lb. 5-leaf springs, which required longer u-bolts.




by:

Easy install , some torque specs with the axle bolts would be nice to have with order. It was easy to find info on Google. Overall good quality product




by:

Not much to say about this item because it’s only a u-bolt kit, but everything went great. The item came on time




by:

Have not installed them yet but they look very good. Heavy duty as expected. One u-bolt is a bit twisted fresh out of the box but it should be easy to correct using a vise. Only one of the 8 I bought was this way. Must have slipped past quality control at the factory. It will not affect its integrity or usage.


Comments
The kit is working great. No problems with it. Many thousands of miles since the install.
Dave L - 08/28/2021


by:

Very good price, works great on my harbor freight folding trailer I modified last year, it upgrades with my 1720axle and 5lug 530c load tires from the 1195axle with 4lug 480b load tires giving me more weight capacity now to strengthen the trailer tongue . Thank you very much




by: 06/23/2022

Great product easy to install and real sturdy




by:

Easy ordering. Correct parts. Fit well




by:

Works as advertised.




by:

Great service and delivery,thank you i look foward to doing more business




by:

Kit was complete, used the old bolts and saving this one for a spare.




by:

These U-Bolts were a perfect fit for my application. After replacing the entire suspension (springs, equalizers, shackles, U-bolts) everything is working perfectly.




by:

Quality product. Works perfectly on my 1968 Plymouth leaf springs.




by:

Needs to have at least another 1.5” of threads


Comments
I do have another set of u bolts to offer. They are part # MR66ZR
MORryde U-Bolts for 5,200-lb to 7,000-lb Round Trailer Axles - Qty 4
$103.41
. The u bolts are 7.75 inches tall and have approximately 3 inches of thread.
-- Etrailer Expert Jenny N - 02/07/2022


by:

Just installed them a few minutes ago. Great product. I liked the extra ribs in the bottom mounting plates. It seemed to add a great deal of strength. I thought the shipping was a little steep but all in all a good experience. Thank you.




by:

Excellent people to work with.
I received
what I ordered, and in two business days.

Only problem, was I ordered the wrong size leaf springs and U-bolts.
But, returned them, no problems. Full refund, minus return shipping.
Also, re-ordered. Hopefully, the correct size, this time. (I was three hours away from my trailer the first time I ordered)


Comments
Second time was a charm! Good product. Fit perfectly. Thank you!
Robert H - 10/17/2018


by:

It's always a pleasure doing with business etrailer, great service and prices thanks


Comments
Working great, no problems at all
Raymond H - 03/13/2020


by:

All parts fit and assembly was straightforward. Instructions were adequate, and the only issue was removing the old Shackle Bolts. The instructions do not caution the installer to not over-tighten the shackle bolts. I had to call to confirm that they should not bind the shackles.




by:

Perfect fit and of good quality, happy with my purchase and wouldn't hesitate to use you again.



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Show More Reviews

See what our Experts say about this Redline Trailer Leaf Spring Suspension



  • Should the Tie-Plate Bend When Tightening Axle U-Bolts
    The recommended torque for a 1/2" diameter u-bolt like the U-Bolt Kit for Mounting 5,200-lb to 7,000-lb, Round Trailer Axles part # APUBR-8 is between 45 and 70 ft lbs. If you are having issues with the tie-plates distorting at 65 ft lbs then I recommend going with a torque setting on the lower end of the above scale. If the tie-plate becomes distorted too much this can weaken the metal but only slight distortion should not be too much of an issue.
    view full answer...
  • Can 3,500 lb Axle be Upgraded to 5,200 lb Axle
    I don't see any issues with running a heftier 5,200 lb trailer axle with leaf springs rated for 3,500 lbs as long as you're mindful of any changes that might need to take place like a longer U-Bolt Kit like part # APUBR-8 and larger tires/wheels as the hubs that fit the larger axle capacity have a 6 on 5-1/2" bolt pattern while your current setup likely has a 5 on 4-1/2" bolt pattern. This also means you'll need to make sure you still have 4" of height clearance from your tires to the...
    view full answer...
  • Kit Needed to Move Trailer Leaf Springs Back Under Axle
    If the leaf springs for your trailer are currently installed so that they are sitting on top of the axle, you can just use a standard U-Bolt Kit to move the leaf springs back under the axle. For a 2-3/8 inch, 3,500 pound axle, you will need the Redline U-Bolt Kit # APUBR-1 and for 3 inch axles with 5,200-7,000 pound capacities, you will use # APUBR-8. I have also attached a helpful installation video for you to check out.
    view full answer...
  • Choosing a U-bolt Kit for Trailer with 1-3/4 Inch Wide Leaf Springs
    When choosing a U-bolt kit for you trailer, you want to choose the correct kit based on the size of your trailer's axle. The width of the leaf springs isn't the main factor. The U-bolt kits you referenced will not both work on the same trailer axle. The # APUBR-8 kit can accommodate both 1-3/4 inch and 2 inch wide springs, but it is designed for use on 3 inch diameter round trailer axles that have capacities between 5,200 pounds - 7,000 pounds. The # APUBR-1 kit will accommodate 1-3/4...
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  • Recommended Slipper Spring And U-Bolt Kit For Trailer With 7,000 Lb Axle
    We have just what you are looking for. The slipper springs we offer for a 7,000 lb axle are part # SP-232275. This is a 5-leaf spring that measures 26-5/8 inches long and 2 inches wide. It is always recommended to replace both sides of the trailer suspension at the same time to make sure they wear evenly and support the trailer evenly as well. You can check out the attached photo with the dimensions noted for the leaf spring. When checking the dimension of the spring you will want to...
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    Image 1 for
  • How to Determine Correct U-Bolt Kit and Leaf Spring Bushing for a 6,000 Lb Trailer Axle
    A 6,000 lb axle is usually going to be 3" in diameter. Therefore, for the u-bolts you can use part # APUBR-8 for 7" long or part # APUBR-9 for 7-1/4" long. You can measure your existing u-bolts or from the bottom of the axle to the top of the leaf spring pack in order to determine which length you need. You can always choose the longer option and cut away any remaining threads if necessary. Most leaf springs for 6,000 lb axles are 1-3/4" wide and will use a 9/16" bolt. If this is the case...
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  • What is the Torque Spec for 1/2 Inch Axle/Suspension U-Bolts on 5200 Pound Trailer Axle
    On the 1/2 inch u-bolts in U-Bolt Kit for Mounting 5,200-lb to 7,000-lb, Round Trailer Axles - 7" Long U-Bolts Item # APUBR-8 torque the nuts to 70 foot pounds each. If you need a torque wrench we have # ALL944001 good for 10 to 150 foot pounds and it has both a 3/8 inch drive and 1/2 inch drive.
    view full answer...
  • Distance From Inside Arc Area Of U-Bolt To Threads For U-Bolt Kit Mounting Kit
    I pulled one of the U-bolts we offer from our warehouse and took a quick measurement for you. The distance from the inside of the inside arced area of the U-bolt, part # CE23003 to the threads on the leg is 4-3/4 inches. The threaded portion is 2 inches. I also pulled another set of U-bolts, part # APUBR-8 and the measurement from the inside of the arc to the threads is the same 4-3/4 inches as well as the threaded portion being 2 inches. This is a 1/2-20 fine thread U-bolt.
    view full answer...
    Image 1 for
  • Replacement Double Eye Leaf Spring For 6,000 Pound Axle on 5th Wheel Trailer
    Based on my research, your Dexter leaf spring is a double-eye leaf spring with a 3,000 pound capacity for your 6,000 pound axle. The original length of your existing springs is 25-1/4 inches. As springs tend to stretch a bit over time, your existing spring likely measures between 25-1/4 inches - 26 inches. To replace the springs on your axle, you can use the # SP-111275 leaf spring. This double-eye spring has a matching length, 25-1/4 inches, and weight capacity, 3,000 pounds, to your...
    view full answer...
  • Torque Needed to Tighten Nuts of 3 inch Trailer Axle
    The torque needed to tighten the U-bolts of a trailer's 3 inch axle like the # APUBR-8 is 70 ft lbs. If you need a torque wrench we have # ALL944001 good for 10 to 150 foot pounds and it has both a 3/8 inch drive and 1/2 inch drive.
    view full answer...
  • Replacement 24-7/8" Long Leaf Springs for 5,000 Pound Axles
    To replace your existing leaf springs the 6-Leaf Double-Eye Spring # SP-222275 will work perfectly. This leaf spring stack measures right at 24-7/8" from eye to eye (center to center) and its designed for 5,300 pound axles (which will work without issue on your 5,000 pound units). For a U-bolt kit I recommend the Redline # APUBR-8, which includes four 7" long U-bolts, two U-bolt plates, and the needed 1/2"-20 hex nuts. I have attached a couple short video reviews on these products below...
    view full answer...
  • Recommended Tandem Axle Trailer Hanger Kit for 40 Foot Trailer
    Yes, the length of the trailer frame will play a part in determining where to position the trailer axles. The axles will need to be placed under the trailer so that 10-15% of the total weight will be on the tongue. I have attached a photo below with the formula you will need to use in order to find out the best spot to place your axles. In regards to parts needed for the above, I recommend the Tandem-Axle Trailer Hanger Kit for Double Eye Springs part # APT5 with the U-Bolt Kit for Mounting...
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    Image 1 for
  • Does the Dexter 7K Trailer Axle with Electric Brakes Come Assemblied
    The Dexter Trailer Axle w/ Electric Brakes part # 8327864-EB does come with the hubs and backing plates already installed so you would be ready to go once it arrives. It however does not come with u-bolts so if you need those as well you can obtain the U-Bolt Kit for Mounting 5,200-lb to 7,000-lb, Round Trailer Axles part # APUBR-8.
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  • Torque Specs For U-Bolt Kit part # APUBR-8
    For the 1/2 inch u-bolts in U-Bolt Kit for Mounting 5,200-lb to 7,000-lb, Round Trailer Axles - 7" Long U-Bolts Item # APUBR-8 torque the nuts to 70 foot pounds each. If you need a torque wrench we have # ALL944001 good for 10 to 150 foot pounds and it has both a 3/8 inch drive and 1/2 inch drive.
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  • Heavier Duty Leaf Springs To Replace Dexter 072-097-00 On 2018 Keystone Cougar 311RES 5th Wheel
    I would be happy to help! Since your 2018 Keystone Cougar 311 RES 5th wheel with tandem 5200lb Dexter axles has the Dexter 072-097-00 leaf springs currently installed the 5-Leaf Double-Eye Spring for 6,000-lb Trailer Axles - 25-1/4" Long # SP-111275 you were looking at will be an exact replacement for you. These leaf spring are the same length at 25-1/4" and the 6000lb capacity of the # SP-111275 will give you the extra support you are looking for. For replacement U-Bolts I recommend...
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    Image 1 for
  • Replacement 6,000 Lb 26 Long Leaf Springs for Trailer
    I have just what you need to replace the leaf springs on your trailer, the 6-Leaf Double-Eye Spring for 6,000-lb Trailer Axles part # SP-053275 which has a 6,000 lb capacity and measures 26" from eye to eye. It does have six leaves so this may raise or lower the trailer marginally but other than that they will be an exact replacement. Please note. u bolts are torque to yield so you'll need to replace them when they are removed and I recommend the U-Bolt Kit part # APUBR-8.
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  • Do The Trailer Suspension Hangers & Equalizers Need To Be Changed Going From 3,500 to 6,000LB Axles?
    You may be able to use the same hangers and equalizers that are already being used on your triple axle trailer. First you will need to determine if you will be changing wheel and tire sizes that will require you to move the axles further apart so that the tires do not contact each other. This may also affect your trailer fenders if the axles are being spread further. If your tire spacing is okay you will then only need to find the larger capacity leaf springs that match the length of...
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  • Correct Replacement Leaf Springs for Grand Design 28BH
    The 5-Leaf Double-Eye Spring part # SP-111275 will be a great fit for a Grand Design 28BH with Dexter 5,200 Lb Axles and it offers a bit higher capacity than standard so you'll get more support and life out of the springs. They will be a direct bolt-on fit and replacement. Please note, new springs are shorter than the old ones as the older ones stretch. For a new u-bolt kit, you'll need the U-Bolt Kit for Mounting 5,200-lb to 7,000-lb, Round Trailer Axles part # APUBR-8.
    view full answer...
  • Recommended Replacement for Dexter Trailer Leaf Spring 072-099-00 and U-Bolts 011-017-01
    The closest match we have for a Dexter Trailer Leaf Spring 072-099-00 is the 4-Leaf Double-Eye Spring for 4,000-lb Trailer Axles part # SP-051275 which will be an exact fit. The only difference being a slightly higher capacity of 4,000 lbs compared to the 3,000 lb rating of the existing. Please note, the leave count difference won't affect fit or function. The for the Dexter U-Bolts 011-017-01 you cab replace these with the U-Bolt Kit for Mounting 5,200-lb to 7,000-lb, Round Trailer Axles...
    view full answer...
  • Correct U-Bolts For 3,500Lb Dexter Axle
    Every 3,500lb Dexter axle we sell has a diameter of 2-3/8" and typically uses a 5-1/2" U-bolt, such as U-Bolt Kit for Mounting 3,500-lb, Round Trailer Axles - 5-1/2" Long U-Bolts # APUBR-1. You may have a 5,200lb Dexter axle, which has the 3" diameter that you seem to have. With this, you would typically use U-Bolt Kit for Mounting 5,200-lb to 7,000-lb, Round Trailer Axles - 7" Long U-Bolts # APUBR-8, but these U-bolts are 7" long, which seem to be an issue in your situation. The only other...
    view full answer...
  • Troubleshooting U-Bolt Kit for Unique Trailer Axle and Leaf Spring Combination
    For the plate and U-bolt for the dimensions you gave, you simply need the U-Bolt Kit for Mounting 5,200-lb to 7,000-lb, Round Trailer Axles - 7" Long U-Bolts # APUBR-8. This will give you the plates and the length of U-bolts you need. The issue is your axle diameter won't be a fit so you would need to fabricate something for stability. Instead I recommend you either change your leaf springs because 3 inches wide is not standard for trailer applications, or you can use the Dexter Trailer...
    view full answer...
  • Trailer Suspension Kit and Leaf Springs Recommendation for a Tandem Axle Boat Trailer 4,600 lbs
    As long as you are replacing everything (hangers, springs, hardware, equalizer), then yes, you can use our trailer suspension kit, # APT5. In fact, this is the kit that I recommend for your trailer. The hangers must be welded to the trailer. The holes that you see in the top of the hangers are actually for welding, not bolt holes. For the leaf springs, you will be much happier with the ride quality of part # SP-212275 for 3,500 lb axles. The other springs you referenced are for 5,000...
    view full answer...
    Image 1 for
  • Replacing 24 Inch Long Leaf Springs on Trailer with Dexter 3,500 Pound Axle
    The closest option we have to the measurements you took on your existing leaf springs is the 3-Leaf Double-Eye Spring # SP-216275. This 3-leaf stack measures 23-1/8 inches from the center of one eye to the center of the other and is designed for a 3,500 pound axle. Older leaf springs will stretch over time so it's not abnormal that the new leaf spring will be shorter than the measurement you took but I do still recommend verifying the length on your current springs. Make sure you have...
    view full answer...
  • Replacement Axle Solution for 2006 Carry On Dual Axle Trailer
    The closest option we have that would work well is the Dexter axle part # 8327864-EB which has the same spring center dimension you have of 74 inches but is 1 inch longer overall at 94 inches from hub face to hub face. This is a 7,000 lb capacity axle with a 3 inch outer diameter and comes with hub drums and brake assemblies that have a wheel bolt pattern of 8 on 6-1/2 inch. You didn't mention what specific hardware you'll need but the part # APUBR-8 is the correct size u-bolt kit you'd need.
    view full answer...


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