1. Trailer Leaf Spring Suspension
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  5. Round Axle - 3 Inch
  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 800-298-8924 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"
  • 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   (174 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.

- APUBR-8
by:

The product seemed good. I didn't use the plates but reused my old plates on my Cedar Creek 34CKTS. (I asked tech support for torque specs but never got a reply) 548103



- APUBR-8
by:

these u bolts and brackets arrived quickly, installed flawlessly, and seemed to be heavy duty. i couldn't be happier. 706252



- APUBR-8
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. 900422



- APUBR-8
by:

good quality and price. 896624



- APUBR-8
by:

Yes our order was delivered in a timely manner thank you......and we are pleased with the merchandise.....again thank you..... 895387



- APUBR-8
by:

work as expected 893996



- APUBR-8
by:

893427



- APUBR-8
by:

892823



- APUBR-8
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. 869708



- APUBR-8
by:

Dia. Of metal was smaller than original but works fine 865310



- APUBR-8
by:

Exactly what I needed 864046



- APUBR-8
by: 08/03/2020

Worked great 855063



- APUBR-8
by:

Great product. U-bolt kit and leaf springs went together well 854081



- APUBR-8
by:

Great fit, easy install and better ride for our trailer. Will buy again. 855481



- APUBR-8
by:

Very good 849730



- APUBR-8
by:

Great ordering process, right product and timely delivery!!!! 837147



- APUBR-8
by:

everything is as excepted for proper fi tment. 814549



- APUBR-8
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. 811653



- APUBR-8
by:

Great costumer service ! Everything I needed to rebuild my trailers suspension. 796284



- APUBR-8
by:

I really appreciate being able to get all of the parts needed to do a job in 1 kit. Fit perfectly. 791048



- APUBR-8
by:

great product great prices 790096



- APUBR-8
by:

Excellent help when ordering items, fast service, not installed yet but hopefully this weekend 773442



- APUBR-8
by:

Thank you for the fast delivery. 770544



- APUBR-8
by:

All of the parts came real quick and they fit perfectly! 766622



- APUBR-8
by:

Promptly delivered at a great price, Thanks etrailer! 756733


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Show More Reviews

Ask the Experts about this Redline Trailer Leaf Spring Suspension

  • Availability of 1/2" Diameter U-Bolt for 3" Axle at Least 8" Long
    The longest 1/2" diameter U-Bolt we have for a 3" axle is the 7" option that comes with the Kit # APUBR-8 that you referenced. We do have longer U-Bolts but they won't match your axle diameter or the thickness that you are looking for. If you are needing to raise the height of your trailer then I recommend using the Dexter Trailer Springs Over-Under Conversion Kit # K71-385-00. This uses 1/2" diameter U-Bolts that are 7" tall but it also includes new spring seats so that your leaf springs...
    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...
    view full answer...
  • 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...
  • 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...
    view full answer...
  • 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...
  • 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.
    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 Suspension Components for 6,000 Lb Axles with 25-1/4 Inch Long Leaf Springs
    Thanks for the photo! I have everything you need to get your trailer back on the road. I have attached my recommendations on the following parts for you trailer as well as the quantities needed. Leaf Springs: part # SP-111275 (4) Equalizers: part # TREQ310 (2) Shackle Straps: part # 115208GALV (8) U-Bolts: part # APUBR-8 (2) Eye Bolts: part # 166079 (12) I have also attached a few review videos on the above products for you as well.
    view full answer...
  • Can 3,500 lb Axles be Changed to 5,200 lb Axles and Parts Needed
    The short answer is yes, you can replace your 3,500 lb axle with a 5,200 lb axle. The longer answer is that while you can change to a higher-rated axle, that does not mean your trailer has a higher weight capacity. The reason is, weight ratings are determined by the lowest-rated component, which can be something other than the axle, like the trailer chassis, for example. So you would need to ensure via the trailer manufacturer what the lowest-rated component is. With that said, in order...
    view full answer...
  • Replacement for Dexter Part Numbers 072-098-00, 011-017-01, and K23-464-00/K23-465-00
    Absolutely, the Dexter leaf spring part 072-098-00 is a double eye spring, designed for 7,000 lb axles, with a 25-1/4" eye to eye measurement. The closest leaf spring we have to that is the Double-Eye Spring part # SP-198275 which is a double eye spring, designed for 7,000 lb axles, with a 24-7/8" eye to eye measurement. The 3/8" difference between the eye to eye measurements will not cause an issue. The Dexter u-bolt part 011-017-01 is a 1/2" diameter bolt, designed for 3" diameter...
    view full answer...
  • Replacement 6k Rated Leaf Springs with Cushioned Equalizers for Tandem Axle Trailer
    The 6-Leaf Double-Eye Spring for 6,000-lb Trailer Axles # SP-053275 that you referenced will work great on your trailer as it matches the capacity you need. The overall thickness of the spring pack is 2-1/4 inches which might be thicker than what you current have and could affect the height of the trailer. For a U-bolt kit you would need the part # APUBR-8 which is for the 6k axles like you have. The equalizers you have now are Equa Flex Cushioned equalizers so for a replacement set...
    view full answer...
  • Parts Needed To Replace 3,500 Lb with 5,200 Lb Trailer Axles
    Yes, you can replace the 3,500 lb Dexter Axles with 5,200 lb Dexter Axles by simply swapping out the old for the new. That said, you will need new u-bolts as the axle will be larger in diameter (2-3/8" vs. 3"). The bolt pattern will also change from a 5 on 4-1/2" to a 6 on 5-1/2" so you will need new wheels/tires as well. Therefore, you will need new axle tubes, u-bolts, and wheels/tires in order to make the swap but these are all bolt-on parts. For the axles you just need to measure...
    view full answer...
  • Changing 3,500 Pound Trailer Axles to 5,200 Pound Axles
    The first thing to consider is if the axle(s) are actually bent. Trailer axles have a bow in them so they are higher at the center than at the ends. When under load the axles straighten out some. That is part of how they get their capacities. If the axles are bent from damage then that is another story. Like you said the 5,200 pound axles that we have include spring seats that are on the bottoms of the axles. In order to have the spring stacks on top of the axles all you would need...
    view full answer...
  • Which Trailer Suspension Hanger Kit Do I Need For 27" Long x 2" Wide Slipper Spring On 6000-lb Axle
    To mount your 27" long slipper springs # SP-160275 you'll need to choose between a kit for single axle trailers or a tandem axle trailer. If you have a single axle trailer you'll want to use the Single-Axle Trailer Hanger Kit for 2" Slipper Springs - 3-3/4" Tall Front # APS6SE. If you have a tandem axle trailer you'll want to use the Tandem-Axle Trailer Hanger Kit for 2" Slipper Springs - 12" Long Equalizers # APT6SE. Since these kits do not come with the mounting bolts to secure the...
    view full answer...
  • Tandem Axle Trailer Spring Hanger Kit and 6K Leaf Springs
    The hanger kit I recommend is part # APT3HD which includes front, center and rear hangers, equalizers and bolts. This kit is good for axles up to a 7K rating and most 3-inch diameter axles are rated for 6000 to 7200-lbs. The linked video will let you see the kit contents. Please note the kit does not include parts to mount the axle to the suspension; for that use # APUBR-8, one kit per axle. For double-eye leaf springs please refer to the linked page that displays all 6K rated springs...
    view full answer...
  • Recommended Complete System Trailer Frame Down for Roadmaster Comfort Ride
    The Roadmaster Comfort Ride Leaf Spring Suspension Kit w/ Shocks - Tandem 8K, 3" Trailer Axles # RM-2460-2580 will fit any 3 inch diameter axles. The closest rated 3 inch diameter axles we have are the Dexter Trailer Axle w/ Electric Brakes - E-Z Lube - 8 on 6-1/2 Bolt Pattern - 95" - 7,000 lbs # 8327834-EB. This axle comes with the hubs and brake assemblies so as long a 80 inch on center spring seats work for your trailer, this will be an excellent choice. You will also need the...
    view full answer...
  • Rebuilding a Tandem Axle Trailer with 6,000 Lb - 7,200 Lb Axles
    I would love to help but are you sure that you have space to lower the trailer 4" - 6"? You will need at least 3" from the top of the tire to the bottom of the fender in order to allow for proper suspension travel. It looks like the fenders on the trailer now will not allow for this therefore I would you to do some measuring before any of the new parts are purchased. I would also need more info on the trailer such as axle capacity (see center label), leaf spring length (eye to eye),...
    view full answer...
  • Can Trailer Upgrade From 3,500 lb to 5,200 lb Axle
    While the simple answer is yes, you can replace your 3,500 lb axles with 5,200 lb axles, it will require a number of all-new parts and isn't going to quite give you the safety margin you are looking for. The reason for that is because capacity is determined by its lowest-rated component, so if you have a pair of 3,500 lb axles, your leaf springs are also likely rated for that much (or very close) and higher-rated axles won't supersede that rating. That said, in order to choose the correct...
    view full answer...
  • How To Find Replacement Leaf Springs for a Palomino Sabre 5th Wheel 12,800 GVWR
    In order to find the correct replacement leaf spring for a trailer you will need to note the type (double eye, slipper), measure the unloaded length, and find the axle capacity. Since you have already determined that you have double eye leaf springs that measure 25-1/2" long then all we need to do is find the axle capacity which is listed on a sticker in the center of the axle tube. That said, I would be willing to bet you either have 5,200 lb or 6,000 lb trailer axles based on the...
    view full answer...
  • 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...
  • Recommended Slipper Spring Suspension for 10,000 Pound Trailer
    For Slipper Springs to install on your trailer that will have a maximum load of around 10,000 pounds, I recommend either the 5-Leaf Slipper Spring w/ Hook End for 6,000 pound Axles # SP-160275 or the 4-Leaf Slipper Spring for 5,000 Pound Axles # SP-231275, depending on the actual axle capacity for your trailer. Then for a hanger kit, which will work for either of the Slipper Springs mentioned above, I recommend the Tandem-Axle Trailer Hanger Kit for 2 Inch Slipper Springs # AP216-H202....
    view full answer...
  • How Does the Single-Axle Trailer Hanger Kit #APS6SE Work with 1.75 Inch Slipper Springs
    To assemble a slipper spring suspension system, you'll need several components: the hangers and bolts (included in the kit APS6SE); slipper springs, such as the 1.75 inch # SP-264275; spring seats such as # TRSS300; and a U-bolt mounting kit such as # # APUBR-8. The 1.75 inch springs attach the same as 2 inch springs would. The hangers attach the springs to your trailer frame. The U-bolt plates attach the springs to the axle. The spring seat welds onto your axle to provide additional...
    view full answer...
  • Can I Replace 4 Leaf Springs With 5 Leaf Springs For The Axle On My Trailer
    Yes, you can replace your 4 Leaf Springs like part # SP-221275 with 5 Leaf Springs like part # SP-111275 as long as you replace all of the springs at the same time. There really isn't any advantage if you want to go with 5 leaf springs over 4 leaf springs. Typically, you always want to try to get the same parts to replace what you already have, but 1/8 of an inch difference per leaf spring won't make much of a difference in how everything fits together. The 5 leaf springs will work just...
    view full answer...
  • Corrosion Resistant Leaf Spring Mounting Hardware for 3 inch Round Axle with 2 Inch Leaf Springs
    We do indeed offer U-bolt and plate kits for a 3 inch diameter axle tube that can be used on 2 inch wide springs, part # APUBR-9 for a 7-1/4 inch long U-bolt or # APUBR-8 for a 7 inch U-Bolt. These bolts and plates are constructed of steel and aren't galvanized. We do offer galvanized U-bolts and zinc plated plates separately. For a 7 inch long by 1/2 inch diameter galvanized U-bolt suitable for a 3 inch round axle and 2 inch wide spring, use part # 1755892-Z. For a U-bolt plate for...
    view full answer...
  • Replacement Leaf Springs on my 2016 Forest River 27RR
    With those measurements in mind and the fact that your camper has a Gross Vehicle Weight Rating (total max weight of camper, gear and water loaded) of almost 9,000 lbs you have one solid choice. Using the 4-Leaf Double-Eye Spring for 6,000-lb Trailer Axles part # SP-221275 offers the 25 1/8" eye to eye you want and uses the same 9/16" bolt size. These springs are rated for 3,000 lbs. each so in total they will give you 12,000 lbs. of capacity. Now your camper is only rated for 8,940...
    view full answer...
  • 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...
    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...
  • U-Bolt Kit Similar to APUBR-8 But with Galvanized U-Bolts
    The U-bolt kit part # APUBR-8 contains the U-bolts part # 1755892 that you also referenced. It just also contains the nuts and plates needed which you would need. For a kit with the # 1755892-Z you would just also need the plates part # TRTP300200 for if you have 2 inch wide springs or part # TRTP300175 for if you have 1-3/4 inch springs.
    view full answer...
  • Recommended Dexter 5,200 lb Axle With Electric Brakes Upgrade
    The Dexter Trailer Axle w/ Electric Brakes - E-Z Lube - 6 on 5-1/2 Bolt Pattern - 86-1/2" - 5.2K # 8327816-EB can be shipped to a residential address. Each axle comes with the 86-1/2 inch hub face to hub face length and spring seats that are 71-1/2 inches on center. Each axle will come with the complete brake assemblies, the hardware to mount the assemblies to the axle's brake mounting flange, the complete hub/drum assemblies including the races, bearings, seals, cap, lug nuts, and grease...
    view full answer...

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Info for this part was:

Expert Research:
Michael H
Expert Research:
Jameson C
Expert Research:
Victoria B
Video by:
Kathleen M
Installed by:
Cole B
Updated by:
Alexander C

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