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  1. Trailer Leaf Springs
  2. Universal Group
  3. Slipper Springs
  4. 30 Inch Long
  5. 1-3/4 Inch Wide
  6. 2900 lbs
3-Leaf Slipper Spring w/ Flat End for 2,900-lb Trailer Axles - 30" Long

3-Leaf Slipper Spring w/ Flat End for 2,900-lb Trailer Axles - 30" Long

Item # SP-039275
Our Price: $54.71
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Trailer Leaf Springs
Shipping Weight: 12 lbs
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Slipper leaf spring acts as part of a trailer's suspension system by providing an attachment point for a 2,900-lb axle. Spring flexes to resist shock and also ensures a smooth ride. Includes bushing with 9/16" inner diameter. Great Prices for the best trailer leaf springs from Universal Group. 3-Leaf Slipper Spring w/ Flat End for 2,900-lb Trailer Axles - 30" Long part number SP-039275 can be ordered online at or call 1-800-940-8924 for expert service.
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Universal Group Trailer Leaf Springs - SP-039275

  • Slipper Springs
  • 30 Inch Long
  • 1-3/4 Inch Wide
  • 2900 lbs
  • 3 Leaf
  • Flat End
  • Universal Group

Slipper leaf spring acts as part of a trailer's suspension system by providing an attachment point for a 2,900-lb axle. Spring flexes to resist shock and also ensures a smooth ride. Includes bushing with 9/16" inner diameter.


  • Leaf spring acts as part of your trailer's suspension system
    • Provides attachment point for your trailer's axle
  • Multiple leaves allow flexibility to absorb road shock
    • Allows for a smooth ride
    • Reduces wear and tear on trailer
    • Ensures level ride on bumpy and uneven surfaces
  • Sturdy steel construction
  • Nylon bushing included
  • Pre-mounted hangers or aftermarket hanger kit (sold separately) required for installation
    • Eye of spring attaches to hanger mounted on trailer frame
    • Slipper end slides into hanger or equalizer


  • Quantity: 1 leaf spring
  • Spring capacity: 1,450 lbs
  • Axle capacity: 2,900 lbs
  • Length from center of spring eye to end of spring (unloaded): 30"
  • Spring width: 1-3/4"
  • Eye diameter with bushing: 9/16"
    • Eye diameter without bushing: 7/8"
  • Leaf thickness: 3/8"
  • Number of leaves: 3
  • Additional dimensions: see table

Flat End Slipper Spring

Part NumberABCDE

Note: To ensure proper axle alignment and suspension performance, leaf springs should always be replaced in pairs.

Leaf springs are an integral part of your trailer suspension system. The leaf springs provide the attachment points for your trailer's axle, suspending it from the frame of your trailer. Each spring flexes to absorb road shock as you travel, allowing the axle to move somewhat independently of the rest of your trailer. This helps to reduce wear and tear on the trailer and also ensures a smooth ride.

Slipper leaf springs attach to hangers that are welded onto your trailer. The eye of this spring will attach to the front hanger with a suspension bolt. The flat slipper end of the spring will slide into the rear hanger. If you have a tandem- or triple-axle trailer, the slipper end will slide into the equalizer that connects multiple springs. The shape of the slipper end of a leaf spring may vary slightly due to differences among trailer manufacturers. Because of this, it's important to check your leaf spring's slipper end before purchasing a replacement spring.

To mount this spring, you will need hangers, a suspension bolt, and possibly a spring keeper bolt, depending on the design of the rear hanger. If you are simply replacing a spring, you may still have hangers welded onto your trailer, but it would be wise to replace the bolts as they can experience wear. It is also recommended that you replace the other leaf spring in your setup at the same time. Because springs can sag and elongate as they wear, this new spring may not exactly match the old one, and the alignment of your trailer could be affected.

If you are fabricating a trailer, you will need to purchase a hanger kit for installation. To determine the type of hanger kit that you need, you must know the specific type of leaf spring that you have, as well as your axle capacity. Depending on the hanger kits used with them, springs can be configured to work for single-, tandem- or triple-axle applications. Hangers and other suspension components can also be purchased separately if there isn't a complete kit that works for your setup.

UNA-039 Universal Group Slipper Trailer Leaf Spring - 3 Leaf - 1,450-lb Capacity

Replaces WIF3

Customer Satisfaction Score:

Customer Reviews

3-Leaf Slipper Spring w/ Flat End for 2,900-lb Trailer Axles - 30" Long - SP-039275

Average Customer Rating:  4.9 out of 5 stars   (164 Customer Reviews)

Slipper leaf spring acts as part of a trailer's suspension system by providing an attachment point for a 2,900-lb axle. Spring flexes to resist shock and also ensures a smooth ride. Includes bushing with 9/16" inner diameter.


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!


The 30" three leaf, slipper style spring was an exact replacement for the broken spring in this old boat trailer. Admittedly, the original design of the trailer suspension is a bit awkward, but the replacement spring fit right where it was supposed to.
Would recommend.


Shipped quick, fit was correct no need to modify anything good price wish they were made here but it’s hard to find correct springs made here


Fit perfectly
Upgraded with this set
of springs
Quick shipping


the old springs had broken into many pieces - and the dimensions of this slipper spring seemed correct. It was - perfect fit


Arrived on time


Really like new springs! Got them sooner than expected and at a great price. I will recommend e-trailer to all of my friends!


Working good still, nice ride for my custom built trailer


The springs were an excellent fit for my older Chrysler boat trailer. The U bolts I ordered were a little too large but that's ok.....They were returnable but I'll keep them for another trailer project in the future. I would recommend dealing with etrailer. Very helpful on the phone and during the order processing. I had the package within a few days.

Charlie Y.


The trailer springs I ordered are working fine. I have no complaints or issues at all. I highly recommend etrailer for anyone in need of any type of trailer parts.


Springs fit great. Very pleased


Super service getting all the right parts. I received the parts in just two days it took about one hour to change both springs .everything fit grate back on the road.thanks


Service was excellent. Ordered leaf springs on Monday and they were delivered two days later. My shipping was upgraded at no additional cost to me. I haven't installed the springs yet but they look great and they should fill my needs. I will order from you for any future needs.


Spring was good, fit as expected. I wish the paint finish was a little more durable but we're talking about a trailer leaf spring here, that's just the way they are. I had to flip the center pin for my application which was easy enough.

The most disappointing thing is the way these were packed, like everything else I have ever ordered from etrailer they were literally just thrown in a giant box with a single sheet of packing paper. The box was of course destroyed by the heavy springs bouncing around in the box. You can tell that at some point at least one spring fell out of the box and the shipping company had to put it back in.


Wth rusted out leaf springs on my trailer but with zero experience replacing them, I contacted etrailer and Shawn was very helpful in selecting the right parts and taking me through the process. She was patient in terms of helping me take the right measurements and suggesting the bolts and pieces I needed to do the job right.

Everything came well packaged and complete two days later. An hour after that the springs were in my trailer and now has a boat sitting on it.



Was very happy with the product. My boat trailer riides better now with the new leaf springs!!!!! I have recommended your company to friends with trailers.


These new leafs raised the suspension 2" as my old ones were really worn out. I was able to change them both within an hour as I had the use of a forklift to hold up the trailer, and impacts to loosen the old bolts. When/if I need them again, I would buy these.


I made a dumb mistake by ordering the wrong slip springs from etrailer. The part numbers for the springs I wanted and the ones I received were very similar, and I must have been distracted by my kids during the ordering process. I called etrailer and they were very professional on the phone and quickly got the correct springs shipped. Their service is good and I will shop with them again.



ordered new trailer tires/wheels, springs, etc... except for the fact they sent me painted not galvanized wheels, but quickly fixed the issue, could n't be happier. priced right, delivered promptly, great quality, etc.. have ordered here before and just as happy.


The springs and other trailer parts I picked up are working great! I really appreciate all the help you folks provided when I was ordering, this was my first time refurbishing my trailer and it made it easy, I will definitely be ordering from your company again when the time comes.


3-Leaf Slipper Spring for 3,000-lb Trailer Axles

Ordered the leaf springs and the quality was good. The shipping was fast and the price was good.


Great product, as described, description of the measurements fit right on.
I would & have recommend E-trailer to friends.

Rich M.


Fit and works as described, Im happy with the product.


They fit perfect it would have been cool if they included new hardware i mean it just 2 nut and 2 bolts.


Exactly what I needed for revamping my boat trailer


Great service and product on the slipper leaf springs. My trailusage and old 1977 dilly trailer everything fit perfect ,Thanks for the support y'all have at etrailers.


I received the order on the 2900 Lbs slipper springs. The box was a little damaged but the springs did not have paint damage. The 1200 Lb springs were bottoming out is why I went to the new spring. The New spring is an exact fit.

Etrailer Expert

Mike L.


Im glad to hear that youre happy with the springs you purchased. Keep in mind that if your old springs were bottoming out because they were overloaded, swapping them out for higher rated springs wont necessarily raise the capacity of your trailer. Youll still be limited by whatever component has the lowest rated capacity, be it the spindles, axle, springs or tires.

Show More Reviews

See what our Experts say about this Universal Group Trailer Leaf Springs

  • Determining Correct Replacement Slipper Springs For 1982 TeeNee Trailer
    I would be happy to help! First you will need to measure the slipper springs on your 1982 TeeNee trailer from the center of the spring eye to the end of the spring as shown in the included diagram, and the width of the spring. You will need to jack up the trailer and secure it with jacks stands to take the weight off of the spring before measuring as if there is weight on the spring it will stretch and give you an inaccurate measurement. Second you will need to determine the weight rating...
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  • Will 3-Leaf Slipper Spring for 2,900-lb Trailer Axles Work On a 2,200 Lb Axle
    The 3-Leaf Slipper Spring w/ Flat End part # SP-039275 is rated for up to 2,900 lbs when used as a pair so these will work great on a 2,200 lb axle. They will be a bit stiffer than the factory leaf springs but this also means there will be more support and they won't wear out as quick. In regards to leaf springs, you can go a bit overrated but you wouldn't want to go with an underrated option.
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  • Replacement Slipper Springs 30 Inches From Center Of Spring Eye To End Of Spring
    We have the replacement slipper springs you are looking for. They are the 3-Leaf Slipper Spring w/ Flat End for 2,900-lb Trailer Axles - 30" Long, # SP-039275. These have a spring capacity of 1,450 lbs and an axle capacity 2900 lbs.
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  • How Much of a Slipper Spring Should be Sticking Out Past the Rear Hanger
    The flat end of a slipper spring should stick far enough through a hanger to allow for the full travel of the suspension without the spring coming out of the hanger. When you have no load on the spring and especially if the frame is currently upside down then the end of the spring will likely be very close to the hanger. Once it is right side up the spring will compress some and push more of the flat end through the hanger. With spring # SP-039275 the hanger spacing should be 28 inches...
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  • Replacement Slipper Leaf Spring Recommendation for 1987 Shoreline Boat Trailer
    The best option we have is the part # SP039275 that you referenced. It's going to be a little longer and a little stiffer than you need most likely since it's for a 2,900 lb axle, but it will work and get the job done.
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  • How to Pick Out 10,000 lb Axle Leaf Springs for Trailer
    To pick out the correct length leaf spring requires you to measure the length of the spring from eye center to eye center without any weight on the trailer. Since you most likely have slipper springs since your axles are 10,000 lb you'd need to measure from eye center to the bend on the opposite end where the spring would fit in the hanger. Keep in mind that old springs will stretch a bit over time. I attached a link to a page that has all of the 10,000 lb axle leaf springs we offer for...
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  • Determine Axle Rating by Measuring to Get Correct 2 Inch Wide Leaf Slipper Springs
    In general, you can measure the diameter of an axle tube to get the rating, though it is more of a guideline and the only way to know for sure is by some identifying marker on the axle and contacting the manufacturer. However, since that isn't a possibility for you, then measuring the tube is the best option, just know that it isn't a 100 percent guarantee. Here are the general ratings: - 1,000 lb – 2,000 lb Axles: 1-1/2 inch - 1-3/4 inch diameter - 3,500 lb Axles: 2-3/8 inch diameter -...
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  • How to Measure for Replacement Slipper Spring on a Cox Tent Trailer
    A similar leaf spring that we have is the Universal Group 2-Leaf Slipper Spring # SP-038275 which is 30" long and rated for a 1,800 lb axle. The 30" is measured from the center of the eye to the end of the leaf spring (see attached picture). The spring is 1-3/4" wide and has an eye diameter of 9/16" with the bushing. Let me know if this doesn't fit your specs and I can see if we have something else for you.
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    Image 1 for
  • Replacement 18-3/8" Long Double Eye Leaf Spring for Yacht Club Pontoon Trailer
    We have exactly what you are looking for with the 3-Leaf Double-Eye Spring for 3,300-lb Trailer Axles # SP-072275. It measures 18-5/16" from center eye to center eye, has a 1-3/4" width. and uses 9/16" bolts. Just be sure that the weight capacity meets or exceeds the rating for your trailer axle.
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  • 1-3/4 Inch Slipper Spring That is 30 Inches Long and Over 2,500 lb Capacity
    We have a couple of slipper springs that may work for you, as they are 1-3/4 inches wide, measure a total of 30 inches, and have the capacity you need. Springs do elongate over time, but you may have to have your brackets re-positioned if the 30 inch length isn't enough (this is the longest available for 1-3/4 inch or 2 inch springs). You will want to get a spring that is as close to your axle capacity as possible without going under it's capacity. - 2,900 lb Axle: 3-Leaf Slipper Spring...
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  • Recommended Slipper Springs for a 2011 Triton LTWC11 2,500 Pound Jet Ski Trailer
    To determine the correct slipper spring for your 2011 Triton jet ski trailer, you will need to know the width of the spring, the length of the spring, and the weight rating of the axle on your trailer. Based on your measurements you provided about your 2011 Triton LTWC11 2,500 pound jet ski trailer, I think your best option would be slipper springs by Redline # SP-039275. This leaf slipper spring is 30-1/4 inches long and 1-3/4 inches wide. It's designed to work on trailers with 3,000...
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  • Slipper Spring for Older Boat Trailer that is 30 inches in Length
    We have a few slipper springs that are 30 inches from spring eye to hook, but you did say eye to eye which would imply a double eye spring. Since 30 inch double eye springs are very uncommon I'll assume you do have a slipper. So for a 1,800 lb capacity spring you'd want the part # SP-038275 or for a 2,900 lb spring you'd want the # SP-039275.
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  • Replacement Slipper Style Leaf Spring for 1984 Tee Nee Trailer
    For your 1984 Tee Nee trailer, the number of leaf springs is not the determining factor but rather the length and the capacity rating. The 3-Leaf Slipper Spring w/ Flat End for 2,900-lb Trailer Axles - 30" Long # SP-039275 is a great replacement option based on your photo as long as your axle capacity is 2900 lbs because each spring is rated for 1450 lbs. If you have a 3,500 lb axle then instead you would want # SP-040275 because it is a higher weight rated spring. If the trailer axle...
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  • Replacement Slipper Springs to Replace 32 Inch Long Springs
    The 30 inch slipper springs we carry don't have a measured radius but the 28 inches you're looking for will work just fine. Your 32 inch springs were likely a little shorter than that originally and have flattened over time. Although probably not the full 2 inch difference but enough that our 30 inch springs will work on your trailer. We carry three different weight capacities that are 30 inches: 4-Leaf for 3,700 pound axles # SP-040275 3-Leaf for 2,900 pound axles # SP-039275 2-Leaf...
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  • 30 inch Long Slipper Spring Recommendation for Boat Trailer
    We have a few options for 30 inch long slipper spring that is 1-3/4 inches wide. For a 3,700 lb axle option we have the part # SP-040275. For a 2,900 lb axle option we have the part # SP-039275. For an 1,800 lb axle you would want the part # SP-038275.
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  • Can Thicker Leaf Springs be Used to Raise Height of Trailer
    Sometimes it is possible to install leaf springs that have more leaves but depending on what you already have installed you may only be able to add taller hangers like the 3-1/4" tall # 28-5. If you can give me some more information on how many leaves you currently have on your leaf springs and what the eye-to-eye measurement is as well as your axle weight rating I can see if we have leaf springs that you can use. I have also attached links to our selections of hangers and leaf springs...
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  • Are Redline 3-Leaf Slipper Springs For 3,000 lb Trailer Axles Sold in Pairs or Individually
    The 3-Leaf Slipper Spring # SP-039275 that you referenced is sold individually. Current pricing is on the product page attached.
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  • Is Leaf Spring Capacity Rating for One Side or Two
    The weight rating on the # SP-039275 spring would be 1500lbs per side, with a rating of 3000lbs for both sides. I have included some more information on installing slipper springs, if needed.
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  • How to Find a Replacement Leaf Spring for a Travel Trailer Labeled EMCO-ABO-72-06
    We probably have something that would work but I can't find any information on the part number you listed. I doubt somewhat that the number you listed is even a part number. If you can give me the dimensions of the spring, it's style (double eye/slipper), and it's capacity I can find you a replacement. Or you can check out the link I attached that has all of the springs we carry. If you use the filters on the page you can narrow down your results to match what you are looking for. Keep...
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  • Is There Cushioned Pin Box for 2017 Keystone Raptor 412
    Your 2017 Keystone Raptor 412 has a Lippert 1116 pin box so for a cushioned replacement the Trailair part # LC155943 is the correct fit and would work great. There isn't a Flex Air that fits your trailer. Now if you are continuously breaking leaf springs that to me would indicate you are exceeding the weight capacity of the springs or are driving on very rough roads. Can you get back to me and let me know what springs you have and what the weight of your trailer is when loaded?
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  • Replacement Slipper Leaf Spring for Triton PWC Trailer
    The best slipper spring option for your Triton PWC trailer is going to be the Slipper Spring part # SP-039275 as it's for up to a 2,900 lb axle, is a 3-leaf setup, and is 1-3/4 inches wide. It does have a flat end though and not a radiused end but that shouldn't be an issue.
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  • Do you have a spring that is 24 center to center and a reverse curve and closed eye?
    We do not have a spring that fits that specifically. In our 3 leaf springs we have two that are closed eye on one end and reverse curve on the other. The # SP-039275 measures 30" center to end of spring and the # SP-178275 measures 22-3/4" center to center. If you are able to go up to the 4 leaf spring we have # SP-231275 which measures 24-5/8" center to center. If you want to go the 4 spring route the added capacity of the 4 leaf would bring you up to 2,500 lbs per spring which will...
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  • Replacing Old Slipper Springs and U-Bolts
    Though the leaf springs are rusty, they do not seem to look pitted, so they should still be fine. It wouldn't hurt to clean them off with WD-40 or a rust remover to make sure they don't get worse. If you did want to replace them though, you could go with something like the Universal Group # SP-040275. As I couldn't tell 100% how wide the leaf spring is, this is a 1 3/4 wide one. It is also much longer with the overall length of 30 inches, so the rear hanger would most likely need to be...
    view full answer...
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  • How to Determine Load Capacity of Trailer Suspension
    We do not recommend that you exceed your trailer's carrying capacity. You will be limited to your axle's rating. The 3-leaf slipper springs, # SP-039275, that we offer measure 24-1/4" long x 1-3/4" wide. These springs are designed for use on trailers with 1,500-lb axles. If your axles are only rated for 1,500 lbs you would be limited to that. I have included a link to our 2000 lbs axles and a FAQ article on trailer suspension systems for you to check out.
    view full answer...

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