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2" Square Trailer U-Bolt (Qty 2)

2" Square Trailer U-Bolt (Qty 2)

Part Number: SP01-160
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Square Trailer U-Bolts Great Prices for the best trailer suspension parts from Redline. 2" Square Trailer U-Bolt (Qty 2) part number SP01-160 can be ordered online at or call 1-800-940-8924 for expert service.
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  • Reviews (209)
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  • Videos (1)
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Redline Trailer Suspension Parts - SP01-160

  • U-Bolts
  • Camper
  • Car Hauler
  • Utility Trailer
  • Square Axle - 2 Inch
  • 5-3/4 Inch Long
  • 3500 lbs
  • 9/16 Inch Diameter
  • Redline

Square Trailer U-Bolts


  • 2" Wide
  • 9/16" Diameter
  • 5-3/4" Long
  • Length of threaded section: 2-1/2"
  • Inner width: 2-1/8"
  • Includes nuts

SP01-160 2" Square Trailer U-Bolt (Qty 2)

Video of 2" Square Trailer U-Bolt (Qty 2)

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

Video Transcript for Redline Trailer Suspension SP01-160 Review

Today we are reviewing SP01160. This is a set of two 2-inch square trailer U-bolts and they are used with U-bolt plates for 2-inch square axles. Those are sold separately as part number 117594 and that plate, along with these U-bolts will secure the trailer axle to the leaf springs and those are mounted to the trailer frame. So, what you have here are two 9/16th inch diameter bolts that are, here we go, 5-3/4 inches long. The threaded portion right here, as you can see, is 2-1/2 inches long and the diameter, inside-to-inside here, is 2 inches. These bolts do come with the nuts that you will need and that is it for Part Number SP01160 from Redline, 2-inchSquare Trailer U-Bolts.

Customer Satisfaction Score:

Customer Reviews

2" Square Trailer U-Bolt (Qty 2) - SP01-160

Average Customer Rating:  4.8 out of 5 stars   (209 Customer Reviews)

Square Trailer U-Bolts


Melissa T Provided excellent customer service. I Would recommend to everyone use etrailer.


Had a leaf spring break on my off-road trailer in Mexico. Left it at a boat yard until I received the parts from trailer & returned to replace. Only took 2 hrs to replace both leafsprinhs, shackles, bolts etc. And we were back on the road.


Good quality product that was shipped promptly. Easy ordering process. I will use e-trailer again soon.


Great Experience!

When I noticed
that the leaf springs on my 44 year old boat
trailer had cracked I thought I would never find replacements.
I fully expected to have to have something custom built.

I was amazed when I found the fantastic diagrams/descriptions
dimensions for replacement springs on

The phone support person was wonderfully helpful in confirming
if items were in stock and ready to ship. The replacement springs
arrived on time and everything bolted up perfectly!

Thanks for such a great site!


Worked great fit was good.
I did not
use standard nuts furnished but used Nylon lock nuts instead.

David P.


No problems....still like it and still going strong on my boat trailer!


Fixed my jet ski trailer without welding. I used this to bolt down all four supports that had begun to crack at the welds. I was concerned that welding would cause the galvanized steel to rust so I found this solution. The heavy construction of this part is very strong and should do the trick. Installation was very easy and quick.


These were bigger than the original ones that came on trailer am going to order another set for the other side


Springs & hanger kit worked well.


Perfect fit. Solid construction.


my friend ordered springs and hardware for my pontoon trailer. man did they get here fast. everything in one box. packed real good. no damage, nothing lost or left out. I finally got everything back together. fits great. i was worried that the springs where going to be to light, but the trailer sits just like new. sorry no pics. I was to greasy to get the camera out. But its like new again. yes i'm gonna be back next time I need parts. and i've already told all my friends with boats and trailers about . I am a happy customer. thanks again. C Finley

Chuck F.


Thanks for your follow up. Parts are still doing fine. I am still veryhappy with my shopping exp. With etrailer, and I have had the opportunityto share my exp with several people hope they come shopping with you.

Chuck F.


Thanks for your follow up. Parts are still doing fine. I am still very happy with my shopping exp. With etrailer, and I have had the opportunity to share my exp with several people hope they come shopping with you.


Great product



Works great I would highly recommend it


These appear to be standard black steel and are of sufficient length to mount springs on top of axle or go with under slung arrangement. The nuts are crimped lock nut style which is ok.

John W.


No problems after one year of hard usage and heavy loads.


SP01-160 U Bolts look to be good quality just wish they came with lock washers.
TRTP200175 U Bolt spring plates work well with these U Bolts. I ordered 4 of these and got 1 and 3 #117594 plates which are very nice and look more heavy duty.
I thought I got stiffed with the one oddball one but I didn't I ordered the cheaper ones and got 3 of the heaver duty ones.
I also ordered #LC281285 Never Fail Tandem Axle Suspension Hardware Kit and one bolt in the kit is to long like its for a 2" wide spring. Guess I will just use one of the old ones I took out.
And 4 #SP-051275 4 leaf double eye leaf springs.
I am redoing the suspension on a fiber splicing trailer that was damaged during hurricane Michael.
All in All etrailer has great prices and fast shipping and great customer service.


Back together no problem


Quality is excellent,I wish I had ordered lock nuts and washers as the u bolts just come with standard nuts.I will just use lock tight and check for loose nuts until they get rusty.If you need trailer parts I have ordered every thing from bearings and races to suspension bushings and spare tire covers from etrailer and have not been disappointed with any thing.


Never been so impressed with the level of service or quality of product. Absolutely not only would buy from them again, I have multiple times. And will continue to do so for any future trailer parts!!!!


Great bolts for my 2" axle over 2" springs. Much heavier than the OEM bolts, not worried about them breaking anytime soon. Chose to cut them down by 1.25" to better fit the spring gap on my overslung axle to maximize spring travel length on my HF trailer, but that was a personal choice, not a requirement.


Good thick U bolts, you can get away with about 1.5" of drop using a spacer block in between the spring and the axle. I was planning on 2" of drop but these U bolts are too short. That is my only complaint, and it is my own fault. I didnt know how thick the leaf springs were going to be so I thought these would be long enough, but not with 3500 lb 4 leaf springs.


Ubolt are well made and heavy duty


Very heavy duty steel and worked for my application. Sadly they are not galvanized; hence the 4 star rating. I prepped, primed, and painted them well so they should hold up. Used to hang fenders on a boat trailer.


I have a huge old miley horse trailer that has seen better days and all of the leaf springs, bearings, etc needed to be replaced, It wasnt like I could go into a name brand parts store to get them either. So when my husband told me he found everything he needed on, I was relieved. I am very happy with the price and the delivery time. The fact that delivery was free was definitely a bonus because the parts were very heavy. I was a little worried about the condition of the parts when they came, the boxes were pretty beat up (very heavy) but so far I haven't found any problems.


Good quality, fit well.


Bought everything to completly rebuild my trailer. All products were good quaility and fit perfectly. The outstanding service was the best part. Never have done trailer work before and I called and talked to support. Got me everything I needed and it was all correct. Upgraded my shipping for free and I still recieved my order quicker than they told me I would.


I couldn’t find parts for my customers boat trailer . Nobody had a complete trailer axle . So I finally found etrailer they answered the phone I had all my measurements they took the time to search out what I was asking for . Awsome sales lady she knew what I wanted and found all my parts so I can replace the spindle on the axle
Nice to talk to a person instead of a answering machine
Thanks for your help


The SP01-160 square u-bolts were perfect for my project. I had to have a certain size dia bolt and length, and these were just what I needed. I located some where I live, but they were very expensive. Found these at Etrailer and their price were half the price what they wanted here. I talked and ordered from Pat and she was very helpful on my order. The shipment was very fast also, ordered on Tuesday and received on Friday. I will definitely order from Etrailer again......Pat, thanks again

William J.


Worked out perfect very sayisified

Show More Reviews

See what our Experts say about this Redline Trailer Suspension Parts

  • U Bolts for a 3,500 lbs Square Axle
    I have a solution for you but we do not have a 2" square u bolt kit for a 3,500 lbs square axle that is 5 3/4" long. You will need to buy the u bolts and u bolt plates separately. The Square Trailer U-Bolt item # SP01-160 comes in a 2 pack, is 2" wide, 9/16" diameter, 5-3/4" long, and has a 2 1/2" length of threads. The U-Bolt Plate for 2" Square Axle item # 117594 comes single and works with 9/16" u bolts.
    view full answer...
  • Correct Replacement for 26-1/2 Long Leaf Spring
    It's not uncommon for new trailer leaf springs to measure shorter than the old leaf springs they are replacing. The reason for this is that leaf springs stretch as they age. Therefore, I do think the 26" long leaf spring options we offer will work for you. In order to find the right one you just need to find your axle capacity; part # e77SR for 2,000 lb, part # e22YR for 4,000 lb, or part # e94SR for 6,000 lb. For new u-bolts, we have the 2" Square Trailer U-Bolt part # SP01-160.
    view full answer...
  • Are 5-3/4 Inch U-Bolts Long Enough for a 3 Inch Tall Axle and Slipper Spring # SP-040275
    The internal length of u-bolts # SP01-160 is 5-3/4 inches so you would not subtract 9/16 inches from that length. The u-bolt plate # 117594-G is 3/16 inches thick. The spring stack for # SP-040275 I just measured and it is 1-7/16 inches thick. Adding in the 3 inch height of the axle and the total comes to 4-5/8 inches. So all of these parts will fit your trailer axle.
    view full answer...
  • Replacement U-Bolt and Plate for Trailer with 2 Inch Square Axle
    For a 2 inch square axle you are going to want u-bolt plate # TRTP200175. The hole spacing on center is 2-5/8 inches by 2-3/8 inches. For matching u-bolts go with # SP01-160. They have a 9/16 inch diameter. I have included a link to a video review for you for the u-bolts.
    view full answer...
  • Can Round U-Bolts Be Used On a Square Axle Tube?
    You need to use square U-Bolts with having a square axle tube. Trying to use round U-Bolts you risk damaging both the bolts and the axle as it creates pressure points rather than distributing the load across the surface. We have a few different size bolts you can see in the list below. 1-1/2" U-Bolts # SP01-120 1-3/4" U-Bolt # 175130 2" U-Bolts # SP01-160
    view full answer...
  • Does the Replacement U-Bolt for 2 Wide, Square Axles Come With Nuts
    The Replacement U-Bolt for 2" Wide, Square Axles part # UBZC716X212X400 does not come with nuts. The bolts are 7/16"-14 so you can pick up nuts for them at any local hardware store. We do however offer a similar u-bolt in a kit which does come with nuts, the 2" Square Trailer U-Bolt Kit part # SP01-160. These u-bolts are slightly longer.
    view full answer...
  • Replacement Leaf Springs and U-Bolts for a 1987 Shore Line Boat Trailer
    Thank you for submitting the photo of your setup. Considering the height of your axle and the amount of clearance you currently have from the axle to the frame of your trailer you wouldn't have enough room to put your axle above the leaf spring. You would barely have a couple of inches of suspension travel. For U-bolts you would want the part # SP01-160 and then for plates you would want the # 117594. Based on the dimensions of your current slipper springs the # SP-040275 that you referenced...
    view full answer...
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  • Replacement Trailer Suspension Parts for Trailer with 2 Square Axle
    It looks like you've got a pretty good grasp on all of this and thank you for the detailed information; it looks like most of the parts you've mentioned will work for you. For the leaf springs, the 26" long # e27SR will be the best option for you since springs stretch out over time and they're right around the capacity of what the axles likely is. The next closest size would be the 25-1/8" # e54SR, but I would be hard pressed to believe that your old ones have stretched out over a full...
    view full answer...
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  • How to Pick Out Replacement Slipper Springs for a Boat Trailer with 2 inch Square Axles
    In order to pick out springs you need to remove the load on the trailer so that the leaf spring is not flattened out at all. You will want to measure from the center of the eye of the spring to the center of where the slipper spring contacts the hanger. If that distance is 26-1/4 inches and the capacity of the axle is 4,100 lbs the # e33SR would fit and work well. The bushing of this spring is 9/16 inch in diameter. You will want to use a 9/16 inch diameter bolt so you can either premeasure...
    view full answer...
  • Thickness of 4 Leaf Slipper Spring for 2000 lb Axle Part # SP01-160
    The 4-Leaf Slipper Spring for 2,000-lb Trailer Axles is 1.04 inches thick at the thickest point. If you need some replacement U-Bolts, we offer them. The part # is SP01-160.
    view full answer...
  • Switching from Slipper to Double Eye Leaf Springs on EZ Loader Trailer
    In order to switch from slipper to double eye springs you'll need new hangers which are going to dictate your height so if you're looking to maintain the same height, you'd want to choose new hangers which are the same height as your existing. The Single-Axle Trailer Hanger Kit for Double-Eye Springs part # APS2 is a good option with 1-1/2" front and 1-1/4" rear. It can then be paired with the 4-Leaf Double-Eye Spring for 4,000-lb Trailer Axles part # e48SR. I also recommend replacing the...
    view full answer...
  • Leaf Spring and U-Bolts Recommendation for a Utility Trailer with 2 inch Square Axles
    Sounds like you have 2 inch square axles on your trailer, for a set of U-bolt you would want part # SP01-160 and then for a U-bolt plate you would want the part # 117594. Now to pick out the correct springs you will want to first find out how much capacity your trailer and axles are rated for. This should be stamped on a plate near the coupler where the VIN is located. If it was a round axle I could give you a pretty good ball park of what the capacity would be, but square axles don't...
    view full answer...
  • Are The Threads on the 2" Square Trailer U-Bolt # SP01-160 Cut or Rolled and Can They Be Cut Deeper?
    The threads on the 2" Square Trailer U-Bolt # SP01-160 are rolled. We do not recommend attempting to cut the threads any deeper on the bolt. You can use a spacer to help make up for the difference if you are not able to find another U-Bolt with the deeper threads you are needing.
    view full answer...
  • Leaf Springs, Hanger Kit, and U-Bolts for a 2 Inch Square Trailer Axle
    Since you do not know the capacity of the trailer axle then you can't go by the capacity of the springs. If the axle is rated for 2,000 pounds and the springs for a 3,500 pound axle then you would still be limited to 2,000 pounds. If you have the inner and outer bearing numbers then that will help to determine what the likely axle capacity is. Since you want to replace the hangers as well as the springs then it doesn't matter which springs you choose. If the axle does end up having a...
    view full answer...
    Image 1 for
  • Replacement U-Bolts For A 3,500lb Axle On A 2020 Grand Design Imagine 22MLE XLS
    Since your axles are round it's actually best to measure with a set of calipers # PTW80157 instead of a tape measure, as you have to kind of eyeball and guess what the actual measurement is. Based on the picture you provided I can see you're under 3" so you would have a 2-3/8" axle unless you had some homemade axle, but I'm assuming with the age of the trailer that you're the original owner from the factory so that wouldn't be the case. For 2-3/8" axles you'll need the CE Smith U-Bolt...
    view full answer...
    Image 1 for
  • What is the Internal Width of Square Trailer U-Bolts # SP01-160
    I went out to the warehouse and measured the internal width of Square Trailer U-Bolts # SP01-160. They are 2-1/8 inches wide on the inside. They are designed for a 2 inch square axle using 1-3/4 inch to 2 inch wide springs.
    view full answer...
  • How To Choose The Correct Leaf Spring U-Bolt Diameter Size On A Trailer Axle
    You will want to choose the diameter size of U-Bolts you need by the axle type (round, square) and the axle diameter. The Redline 2 Inch Square Trailer U-Bolt, part # SP01-160, you have referenced is for a 2 inch square axle. It is a 9/16 inch diameter bolt. The 9/16 inch diameter U-Bolts are used on 1-3/4 inch and 2 inch square axles, 2-1/2 inch round axles, 3 inch round axles, and 3-1/2 inch round axles. I am including a link to a page of the available 9/16 inch diameter U-Bolts. The...
    view full answer...
  • How to Increase Ground Clearance with Slipper Springs.
    I can help you figure out how to get more ground clearance from your trailer. All of our over under kits have only been tested on a double-eye spring setup, these are secured on both ends unlike slipper springs which are not. I would worry that it could become unsafe since the weight of the trailer was pulling on the axle and once you switch the location of it all the weight will now be pushing down on the rectangular axle. While we don't have a specific over under kit for rectangular...
    view full answer...
  • Using Nylon Lock Nuts On 2 Inch Square Trailer U-Bolt SP01-160
    For the 2 inch Square Trailer U-Bolt, part # SP01-160 you purchased, you can use nylon lock nuts that would work for a 9/16 bolt.You would want to make sure you use nuts of equal strength and that they match the thread and size.
    view full answer...
  • What Type of Thread Does 2" Square Trailer U-Bolt Have
    The 2" Square Trailer U-Bolt # SP01-160 has fine threads (SAE) so it is 9/16"-18 or 18 threads per inch. This comes with 2 U-bolts and includes the nuts required for installation.
    view full answer...
  • U-Bolt and Plate Recommendation for Trailer with 2 inch Axle
    We have axle u-bolts for 2 inch square axles like the # SP01-160 that you referenced but these are much longer at 5-3/4 inches long instead of what I believe I am understanding you say you want 2-1/2 inches in length. This comes with nuts for each side of the u-bolt but for plates you'd then want the # 117594.
    view full answer...
  • Parts Needed For An Over-Under Suspension Conversion On A Boat Trailer
    Hey Travis, Since you have a square tube axle the Dexter over-under conversion kits aren't going to have the correct spring seats. We don't currently offer square tube spring seats so you'll need to source them somewhere else and then have a qualified welder weld the new spring seats on the bottom of the axle at the same spot as the originals. You'll want to measure the axle to make sure you're getting the correct size. From there you'll just want to replace the u-bolts because as they...
    view full answer...
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  • Looking For A 2" Square U-Bolt At Least 5-1/2" Long
    Hello Ben. We do have the 2" Square Trailer U-Bolt # SP01-160 which sounds like it will fit your needs. This has a 9/16" diameter and is 5-3/4" long overall. You can use it along with the U-bolt plate # 117594.
    view full answer...
  • Recommended Torque Specifications for U-Bolt # SP01-160 in a Slipper Springs Trailer Setup
    Since the # SP01-160 u-bolts are 9/16 inches in diameter the torque rating is from 65 ft/lbs - 95 ft/lbs. I have linked a Help Article on Slipper Spring Trailer Suspension System Review to this page that lines out the torque ratings of the different diameter u-bolts for you to check out. I linked all the parts you mentioned to this page for your purchasing convenience.
    view full answer...

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