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Tandem-Axle Trailer Hanger Kit for Double-Eye Springs - 3-1/4" Front/Rear, 5-7/16" Center

Tandem-Axle Trailer Hanger Kit for Double-Eye Springs - 3-1/4" Front/Rear, 5-7/16" Center

Item # APT4
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Trailer Leaf Spring Suspension
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Shipping Weight: 26 lbs
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Redline Trailer Leaf Spring Suspension - APT4
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Leaf-spring mounting kit includes 3-1/4" tall front hangers, 5-7/16" tall center hangers, 3-1/4" tall rear hangers and necessary hardware. Equalizers are 6-1/4" long. Components for mounting axle to springs sold separately. Lowest Prices for the best trailer leaf spring suspension from Redline. Tandem-Axle Trailer Hanger Kit for Double-Eye Springs - 3-1/4" Front/Rear, 5-7/16" Center part number APT4 can be ordered online at or call 1-800-940-8924 for expert service.
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  • Reviews (27)
  • Q & A (0)
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Redline Trailer Leaf Spring Suspension - APT4

  • Hangers
  • Suspension Kits
  • Spring Mounting Hardware
  • Double Eye Springs
  • Tandem Axle
  • Redline

Leaf-spring mounting kit includes 3-1/4" tall front hangers, 5-7/16" tall center hangers, 3-1/4" tall rear hangers and necessary hardware. Equalizers are 6-1/4" long. Components for mounting axle to springs sold separately.


  • Attaches 4 leaf springs (sold separately) to your trailer frame
  • Includes:
    • (4) 3-1/4" Tall front and rear hangers (28-5)
    • (2) 5-7/16" Tall center hangers with 3/4" bolt holes (115919)
    • (2) 6-1/4" Long curved equalizers (TREQ458)
      • 3/4" Diameter center hole for mounting to hanger
      • 9/16" Diameter end holes for attaching to springs
    • (8) 2-5/8" Long shackle straps (115052)
    • (12) 3" Long x 9/16" diameter shackle bolts (9163B)
    • (12) 9/16" Diameter locknuts (916DLN)
    • (2) 3-1/2" Long x 3/4" diameter wet equalizer bolts (126A1LN)
    • (2) 3/4" Diameter castle nuts (165093)
    • (2) 2-1/4" Long cotter pins (165649)
    • (2) 1/8" MPT grease zerks (1610)
  • Designed for use on trailers with tandem, 2,000-lb to 7,000-lb axles
  • Does not include components for mounting axle to springs

APT4 Tandem Axle Hanger Kit - 1.75" Double Eye Springs - 2,000 lbs to 7,000 lbs

Customer Reviews

Tandem-Axle Trailer Hanger Kit for Double-Eye Springs - 3-1/4" Front/Rear, 5-7/16" Center - APT4

Average Customer Rating:  4.7 out of 5 stars   (27 Customer Reviews)

Leaf-spring mounting kit includes 3-1/4" tall front hangers, 5-7/16" tall center hangers, 3-1/4" tall rear hangers and necessary hardware. Equalizers are 6-1/4" long. Components for mounting axle to springs sold separately.


The bushings seem cheap but otherwise seems to be solid.


Everything went together well. The trailer is working fine now

everything is still holding together and working fine
DANIEL D - 12/15/2021


This hanger kit and leaf springs for my tandem boat trailer was PERFECT! I did one side at a time. Once we got the old crap off the trailer, reassembly was a snap. It took about three hours from start to finish. Most of the time was spend removing the frozen center bolt from the old equalizers. I'm very happy I opted for the two center bolts to be "wet bolts". Thanks again, I would definitely recommend etrailer to my friends. Regards, Bob

XRMARTIN-Daytona - 03/16/2017


I have ordered from Etrailer a few times now, The service is always great and fast shipping. They have the best prices around. Where I live I have 24 miles of rough dirt road so am always replacing parts on my trailers. Their products hold up to the test of my road. Always a perfect fit too!

everything is still holding up very good! Thank you guys for the excellent service!
Frank L - 08/17/2015


Just finished welding these up. Great quality. Bends are aligned and square!


Disappointed with the Made In China for the equalisers though quality seems to be ok.

Weld on pressings for the shackles and straps were poorly finished, with sharp edges that needed finishing before assembly/paint prep. Country of origin unknown.


Kit purchased to repalce damaged components on an existing 70's era trailer. The complete hanger kit was cheaper than purchasing the individual parts I needed. The hangers were not used but the equalizers, shackels, and bolts were direct replacements to restore my trailer to tip top shape. I added some nylon spring eye bushings to complete the job!


I have ordered from etrailer many times and they are always prompt with their shipments and the parts arrive as ordered. Customer service A+.


I was very pleased with the quality of the APT4 kit I received . I had a small issue due to the kit was short 2 bolts and nuts. Etrailer toke care of the issue promptly by sending the missing parts with out question. I would use etrailer for all my future needs.


Product was just as advertised. Nice to just order a kit and not have to worry about forgetting something. My only complaint was the packaging as everything was just loose in a cardboard box. Surprisingly nothing fell out in transit considering all the nuts, zerks and cotter pins were rolling around and there was a hole in the side of the box.


We have bought these hanger kits from etrailer before and are very happy with the product. Their shipping is quick and the value is exceptional.


Good value. Very complete kit of everything you need at a great price.

Product has been trouble free and held up very well.
Kraig H - 07/12/2020


Impressed with quality of parts. Customer service was awesome in helping me find the right parts. Definitely will do business in future.


Package arrived on time. All items in great shape. I'm looking forward to doing business with ETrailer in the future. Walker


Fast delivery and just as discriced


Great products and prices.


The item was a high quality at a great price. Shipping was fast. Communication was excellent.


Everything I bought looks amazing, I can’t wait to install, all quality looking parts


VERY quick shipment and everything is perfect!! What a great company to deal with.


Excellent product, would purchase again


The product came exactly as described, fast shipping, I was very pleased with service!


High quality, perfect fit. Can't beat the price.




all the parts i orderd came fast and fit perfect.

Show More Reviews

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

  • Is It Possible to Move Square Axles Below Leaf Springs
    Based on the picture you submitted that shows a square axle welded to a mount which is then welded to a leaf spring you would need to have someone qualified use a cutting torch to remove the mount from the spring so that you could then use a u-bolt style of mounting kit to attach the spring on top of the axle. To do this you will need to know the dimensions of the axle. We have kits for square axles that range from 1-1/2 inch square axles up to 2 inch axles. Once you determine the size...
    view full answer...
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  • How to Determine where to Place Axles on a 17 Foot Car Trailer or Any Trailer
    Placement of the axles depends on several factors and there is a formula that you can follow to determine the best placement of the axles. Take a look at the picture I have included which explains how to determine where axles should be placed. Once you have the axle locations determined you can look at what hanger kit will work best for you. I have included a link to the options for you.
    view full answer...
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  • 5th Wheel Trailer Rides High In the Front When Connected to a 2015 Ram 2500 4x4
    You covered the basic ways of adjusting the height of a 5th wheel trailer (lowering the hitch and raising the pin box). And since the axles are already below the leaf spring stacks there is one other thing that you can do to get more height at the rear. You can have the existing suspension hangers cut off and new, taller ones welded on. We have several heights of hangers available and I have included a link to the hanger main page for double eye leaf springs for you. The cutting and welding...
    view full answer...
  • Trailer Lift Recommendation for a Trailer with Axles Over Springs
    Aside from moving the axles below the leaf springs the only other way we recommend you lift a trailer is by installing taller spring hangers on the trailer frame. What you would need to do is measure the dimensions of your current hangers and then compare them to the hangers at the attached link and then go with ones that will give you the amount of lift you need.
    view full answer...
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  • Is Welding Required to Install the Tandem-Axle Trailer Hanger Kit # APT4 on a Trailer
    Yes, you will need to have a qualified welder weld on the hangers of the Tandem-Axle Trailer Hanger Kit # APT4 on your trailer.
    view full answer...
  • Way To Raise Trailer Suspension When Axles are Under Leaf Springs
    If your axles are currently under the leaf springs then an over-under kit would not be the correct product to use as it would not actually raise your trailer. It would lower it. If you cannot use an over/under conversion kit then the only other way to raise the height of the trailer is to have the old suspension hangers cut off and new, taller ones welded on by a qualified professional welder. I have included a link to the hanger main page for you. You can also try raising the pin box...
    view full answer...
  • Can a Trailer with Axles Under Leaf Springs Be Lifted Further
    If you already have your axles mounted below the leaf springs the only way you can add height to a trailer is to go with taller hangers for the suspension. You would need to have the old suspension hangers cut off and new, taller ones welded on by a qualified professional welder. I have included a link to the hanger main page for you.
    view full answer...
  • Can Suspension Kit # APT4 Be Used on Trailer with 3 inch Shackles
    3 inch long trailer suspension shackles is a pretty common size although it is longer than most. The hanger/equalizer kit part # APT4 includes shackles which are 2-5/8 inches in length. This is a much more common size and would work well on your trailer. The size difference would not matter since you are replacing all of the components anyway.
    view full answer...
  • Troubleshooting Rear Tires Wearing on Inside for Dual Axle 5th Wheel Trailer
    Thank you for all of that information. From everything that you described it sounds like you are overloading your rear axle. Even though your axles are rated for 8K each and you only have 12,420 lbs on your axles, if your rear tires are wearing on the inside tread then you have too much weight over the rear axle and you need to adjust cargo around in your 2019 Grand Design 367 BHS Reflection 41. Axles naturally have an arced shape and when they are weighed down correctly they straighten...
    view full answer...
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  • How Much Should Wet Bolts be Tightened Down for Hanger Kit # APT4
    When installing the wet bolts, like what comes with the Hanger Kit # APT4 that you referenced, we recommend tightening them down so that the knurls are no longer visible and then backing them off just a little bit. There is no torque rating for wet bolts and you are correct that if you tighten them down too much then it will "lock up" your suspension some. If you follow the procedure highlighted above you will have them tightened correctly.
    view full answer...
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  • Replacing Trailer Leaf Spring Hangers
    Thank you for including your diagram, but unfortunately some of the information is not legible. In any case if you are replacing existing parts with different ones you will want to mock up the suspension set-up by first just tack welding the hangers. This will enable you to see if the whole system fits together and if you need to select a new equalizer. The linked diagram provides general axle placement guidelines for new construction. Generally, you want the eye of your spring to be...
    view full answer...
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  • Tandem Axle Suspension Kit Recommendation that Uses 6-1/4 inch Long Equalizers
    We have a kit that uses equalizers that are 6-1/4 inches in length. For that you would want part # APT4. This leaf-spring mounting kit includes 3-1/4" tall front hangers, 5-7/16" tall center hangers, 3-1/4" tall rear hangers and necessary hardware.
    view full answer...
  • Tandem Axle Trailer Suspension Hanger Kit with 8 Inch Long Straight Equalizers
    The tandem axle version of trailer suspension hanger kit # APTT1 is actually # APT1. I have also included a link to all of the tandem axle kits we have.
    view full answer...
  • How to Find the Correct Replacement Equalizer
    The Tandem-Axle Trailer Hanger Kit for Double Eye Springs # APT5 may have the correct equalizer but you will need to measure the current equalizer to find out. The length from the center of the left-most eye to the center of the right-most eye of your equalizer needs to be the same as the 7-3/4 inch measurement in this kit. Since you said the shackles are hitting the frame I recommend using a kit with a center hanger that is longer than the 3-3/4 inch hanger that comes with Kit # APT5....
    view full answer...
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  • Will 5-7/16" Tall Center Hanger for Double-Eye Springs Work with 9/16" Bolt
    Even though the 5-7/16" Tall Center Hanger for Double-Eye Springs # 115919 has a 3/4" diameter bolt hole, this is actually designed to work with 1-3/4" wide double-eye leaf springs that install using 9/16" diameter bolts which I think is what you're getting at, so this should work perfectly for your application! If you check out the Tandem-Axle Trailer Hanger Kit for Double-Eye Springs # APT4 you can see where these same hangers are used in a kit that comes with 9/16" bolts so having that...
    view full answer...
  • Recommended Hanger Spacing for 24-7/8 Inch Long Leaf Spring with APT4 or APT3HD Hanger Kit
    Based on my research, when using the Universal Group Leaf Springs # SP-222275 that has a spring eye length of 24-7/8 inches with either the Redline Tandem Axle Hanger Kit # APT4 or # APT3HD, you will want a distance of 29-1/2 inches between the hangers on your trailer. Both hanger kits you referenced include everything needed to attach 4 leaf springs to your trailer frame. I have included a couple short video demonstrations on these kits along with an article on positioning a trailer axle...
    view full answer...
  • Availability of Replacement or Repair Kit for TruRyde Trailer Suspension Equalizer
    We do have a Tandem Axle Hanger Kit # APT4 which comes with the equalizer you referenced, # TREQ458, as well as front and rear hangers, center hangers, shackle straps, shackle bolts, locknuts, wet equalizer bolts, castle nuts, cotter pins and grease zerks.
    view full answer...
  • Adding Lift To 2003 Jayco Single Axle Tent Trailer
    I spoke with my contact at Jayco about your 2003 single axle trailer. There is no lift kit available but we may have an option for you. If your 1-3/4 inch axle is round and you have underslung leaf springs, I recommend installing a new spring seat on top of the axle, like the Spring Seat for Typical 2000-lb, Round Trailer Axles, part # TRSS175. Simply flipping the axle is not an option because axles are made with a slight arc so that they can handle the load on the trailer. When placed...
    view full answer...
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  • Can Higher Capacity Leaf Springs be Used on a Trailer Weighed Down by a Bobcat Tractor
    I do not recommend using higher capacity springs because that will give you a stiff ride. Also the different springs may require a different hanger orientation and since the hangers are welded on this is a professional job since the old ones have to be cut off and new ones welded on. Even if you added the higher capacity springs, the axle and tire capacities will not also increase so you could easily overload the trailer. With a load on the trailer, it is going to compress the springs....
    view full answer...
  • Correct Hanger Spacing for the Tandem-Axle Trailer Hanger Kit Part # APT4
    The position of the axle should dictate the position of the springs and hangers not the other way around. With that being said, in order to determine proper placement of the hangers you will want to take the the distance between the two eye holes on the leaf spring which on part # SP-212275 is 25-1/8". Add that to half of the length of the equalizer from the center of the two lower bolt boles which for the one included in part # APT4 is 3-1/8". You would then need to subtract 1/2" for the...
    view full answer...
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  • Hanger Spacing Recommendation for Using Trailer Leaf Springs SP-053275 with Hangers APT4
    When using the trailer suspension hanger kit part # APT4 with a leaf spring that is 26 inches long like the part # SP-053275 you will want to have the hangers spaced 30-1/4 inches apart.
    view full answer...
  • Distance Between Hangers with 26 Inch Leaf Springs
    We don't carry the MR4 leaf springs but based on my research they look like they are 26 inch double-eye springs like part # SP-053275. For springs of this length and the Tandem-Axle Trailer Hanger Kit for Double-Eye Springs # APT4 the hangers are going to be spaced 30-1/4 inches apart. I have added a link to a video review of the hanger kit as well as a couple help articles on trailer suspension which I recommend checking out.
    view full answer...
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  • How Can I Get More Ground Clearance if my Axles are Already Converted Under the Springs
    From that point the only option you will have to raise your camper would be to add longer spring hangers. Depending on your setup you can get a couple of inches out of these. Measure yours from the frame to the bolt hole and get longer ones like the Front/Center/Rear Hanger for Double-Eye Springs part # 28-5 that is 3-1/4" tall. The Tandem-Axle Trailer Hanger Kit for Double-Eye Springs Kit part # APT4 is also a great way to achieve this and refresh all of the other suspension components.
    view full answer...
  • What Is The Tallest Leaf Spring Hanger Kit We Offer?
    The tallest Leaf Spring Hanger Kit we offer is the Tandem-Axle Trailer Hanger Kit for Double-Eye Springs - 3-1/4" Front/Rear, 5-7/16" Center # APT4 which uses 3-1/4" tall front and rear hangers, and 5-7/16" center hangers. The included equalizers are 6-1/4" long, and the included shackles are 2-5/8" long. The hangers will need to be welded to the frame of your trailer by a qualified welder. If you can tell me what the weight rating of your axle is I would be happy to recommend the correct...
    view full answer...

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