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Shackle Bolt with Locknut for Double-Eye Springs - 3" Long

Shackle Bolt with Locknut for Double-Eye Springs - 3" Long

Item # 166081
Our Price: $7.66
Trailer Leaf Spring Suspension
Orders above $99 qualify for Free Shipping
Shipping Weight: 0.32 lbs
In Stock
ABS Fasteners Suspension Bolts - 166081
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9/16" Diameter spring-retainer bolt is used to mount double-eye spring inside front or rear hanger. Includes locknut. Great Prices for the best trailer leaf spring suspension from ABS Fasteners. Shackle Bolt with Locknut for Double-Eye Springs - 3" Long part number 166081 can be ordered online at or call 1-800-940-8924 for expert service.
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ABS Fasteners Trailer Leaf Spring Suspension - 166081

  • Camper
  • Car Hauler
  • Utility Trailer
  • Suspension Bolts
  • 3 Inch Long
  • 9/16 Inch Diameter
  • ABS Fasteners

9/16" Diameter spring-retainer bolt is used to mount double-eye spring inside front or rear hanger. Includes locknut.


  • Suspension bolt attaches leaf spring to front or rear hanger
  • Included locknut secures in place on bolt


  • Diameter: 9/16"
  • Length: 3"

166081 Shackle Bolt with Nut

Video of Shackle Bolt with Locknut for Double-Eye Springs - 3" Long

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

Video Transcript for Redline Trailer Suspension 166081 Review

Today we're going to take a look at the 3-inch-long shackle bolt with the lock nut for double-eyed springs. This bolt will secure leaf springs to your front or rear hangar of your trailer's suspension system. Does include this lock nut to secure the bolt into place. Now the bolt itself is a grade-5 bolt. The overall length on this bolt if we measure it from the bottom of the head to the very end and see is going to be right at 3 inches. The bolt size is a 9/16th diameter by 18 threads per inch. The bolt head size is 13/16ths of an inch.

I got example here's a socket. You can see it will fit the head perfectly and then the lock nut which goes on the end right, the size on that is 7/8ths of an inch. You can see it fit rights into a 7/8ths inch socket but that should do it for the review on the 3-inch-long shackle bolt with the lock nut for the double-eyed springs.

Customer Satisfaction Score:

Customer Reviews

Shackle Bolt with Locknut for Double-Eye Springs - 3" Long - 166081

Average Customer Rating:  4.8 out of 5 stars   (616 Customer Reviews)

9/16" Diameter spring-retainer bolt is used to mount double-eye spring inside front or rear hanger. Includes locknut.


I think etrailer is Great. I think their customer service is fantastic. My wife and I were in Arkansas, 1200 miles from our home in Ft. Myers Florida. I replaced the original springs on our trailer with new heavy duty springs, but never changed the hangers or bolts. Our trailer was riding very poorly, we needed new hangers and bolts badly because we were headed on a very long 9000-mile trip with many stops all the way to the Monterey CA. etrailer found us a UPS Store along our route to send us the parts that we needed. Many thanks to etrailer for great parts and Fantastic customer service and for helping us with our most Wonderful Adventure!


I am very pleased with the quality and obvious necessary strength of these shackle bolts and the locknuts. I do wish the free shipping incentive was "Orders Over $50" vs $99 as well as a quicker turnaround for delivery. I ended up having my local trailer guy providing the 3 shackle bolts I needed but I will use these to replace the other 3 eventually and have one to spare. Overall though, I am pleased with this order and appreciate having the selection of components I needed.

My trailer is still going strong and the last periodic maint check of my shackles, bolts, and nuts is A-OK.
Nathan - 08/06/2022


When I ordered my kit from etrailer to replace the double-eye leaf springs on my 1970 Shasta Trailer, I decided to save a few bucks and get the bolts at my local hardware store. Big mistake! You wouldn't think a simple 3 inch bolt would be hard to find in your local hardware store. But in fact, i checked five hardware stores and none of them had this particular bolt. What a waste of time! I should have learned my lesson by now, and just give all my parts business to I have probably spent more than $1000 in the past several months refurbishing our 1970 Shasta. Totally satisfied with the selection at etrailer, and the service is second to none!


I received my order in a timely manner, however, whomever packaged it just threw the bolts and nuts and bushings and shackles in the box loosely, when i opened the box I took packaging paper out and threw in my recycle bin, I then only found 2 nuts and 3 bushings out of 4 each expected. I went threw packaging paper and found missing parts, would it be too much trouble to put these loose parts in a Baggie or something?


Jamie is AMAZING! She knows the business and will do whatever it takes to make you happy. The parts she supplied me with were EXACTLY what I was looking for. As of this writing I have contacted her about another order.

After one year and about 15K miles pulling loads of around 7K I couldnt be happier! These parts were a tremendous upgrade to my existing parts.
Karl - 01/13/2023


I took the day off work to work on my trailer today. To my surprise, I opened my shipment form etrailer, to find some of my order and a box of used worn parts. VERY frustrating to say the least.

That would be very frustrating I am sorry to hear that! I have sent your information to our customer service team to make sure you get squared way.
-- Etrailer Expert Brooke M - 09/22/2022


First, Brittany is extremely helpful, knowledgeable and reliable. She's a keeper.Second, products are good also:)


I bought springs, shackles, bolts, bushings, etc, the whole kit to redo my dual axle trailer suspension. Excellent instructions online with diagrams to show you what/how to measure properly so you can order the correct parts the first time. Everything arrived on time, fit as it should, and everything works well without issues after one year's time. Excellent customer support from Paula when I had questions, and an email following up after one year. Who does that these days? Almost no one. I would recommend this company for all your future trailer needs.


Bolt and nut


We have not tried to install yet, will let you know after installation. Thanks


I bought springs, shackle bolts, and u-bolts and plates. Everything was great and fit perfectly. Only issue were the u bolts which were not galvanized. However, at a local trailer store, I bought galvanized U bolts for $4.50 each.
For the DYIers, taking the old ones off took more than 4 hours for each side. My existing shackle bolts were so heavily rusted that I had to cut three off with a hack saw. Difficulty was confined space to operate hack saw with boat still on trailer. However, reassembling the new springs was less than 45 minutes each side.
Must have tools are large diameter 3/4-13/16-7/8 deep sockets (6 point), 2 2 foot long breaker bars and a can of PB blaster.
For safety: Good quality jack stands, minimum of 3--don't rely on the front trailer jack as it may roll.
By the way, I did these myself and I am 64 years old.


I was happy with the products and the shopping experience. I do wish the shipping would have been a little faster, but you can't have it all, I suppose.


Other than the parts taking a month to process, once they were gathered and packaged, they were delivered within 2 days! I replaced both sides with new 3-leaf double eye springs, 4 shackle straps, 6 shackle bolts, 2 Dexter U-bolt plates, and 2 U-bolts. They were really easy to replace and I did it quickly. Looks great, gonna take her out soon.


Great experience start to finish. Jesse was very experienced and knowledgeable about what I needed for my utility trailer. All parts fit and were 100% perfect and worked fantastic....highly recommend


I bought a used Jon Boat trailer and first time out the shackle bolt gave out. Perfect fit for my application and I really like the way the nut was made so that it locked on the bolt. I used these with the Never Fail Bushings. I had to drill out the shackle to accommodate this beefy bolts but that wasnt a big deal. I ended up doing both sides that had standard bolts instead of wet bolts. Not sure why only 2 were regular 3/8 inch bolts.


I purchased the 3000# axle springs and all mounting hardware to replace the old ones on my 1963 travel trailer. My trailer no longer leans to the left and goes down the road better than new. I should have done it many year ago. I received my package on time and installation was easy and fit perfect. Thanks Bridget


I replaced my leaf springs and shackles on my trailer and these bolts fit perfect. They come with lock nuts and they definately won't be coming loose. If I had to do it again I would have bought an impact wrench to make the job go quicker.


I fixed my 5 wheel today with all the parts I got from you changed,all the equlizers and the shackles on both sides,my fifth wheel camper was blowing tires left and right.the shackles were almost wore all the way through the the end of the shackle.the tires were out of line with a straight line by two inches,when I got the new parts on the tires were right in line.thanks for the great prices and your web sight was easy to use and fast shipping I will be ordering from you again.thanks ron

The equilizers worked great I havent blown a tire yet thanks for all your help Ron
Ron A - 07/20/2016


Would not go into the shackles.lve done 3 other trailers without a problem


I have had these on my trailer for a year. They installed easy and have held up well to use. They were a good price and have been a good product. Thank you.


All items were delivered on time. Everything fit perfectly on the trailer. I would definitely recommend etrailer products.


3 were right 1 was longer than the others so couldn’t use. Ordered 4 the same how is this missed when packaging

I am not sure how that happened however I will have our customer service team reach out to you.
-- Etrailer Expert Jenny N - 09/08/2022


Well made, hard steel, good threads. This bolt/nut set is more expensive than local no-name bolts, but is of superior quality.

No failures to date. A coat of primer on the ends controls corrosion.
Sam B - 06/25/2017


Great product, great service, can't say enough good things about trailer...

Still going strong!!! I dont really beat on my stuff. I was given a trailer that had seen better days, I rebuilt most of the mechanicals on it & its still serving me well…Thanks for the follow up though…
William - 01/21/2019


I ordered 14) 3" bolts and received 11)3" and 3)3-1/2". I called and spoke to Teresa who took care of the problem immediately. Thank you for the great customer service.

Show More Reviews

See what our Experts say about this ABS Fasteners Trailer Leaf Spring Suspension

  • Can Shackle Bolt with Locknut, # 166081 Be Used in Place of Dexter Bolts
    You will be able to use the Shackle Bolt with Locknut, # 166081, in place of the old Dexter bolts you have. If the bolts were shorter, you would not be able to use them but since they are basically the same length, you should not have any problems. I have included a link to a video on replacing shackle bolts that you may find helpful. We have numerous shackle links depending on what size you need. I have included a link to them for you to view along with a link to our FAQ articles on trailer...
    view full answer...
  • Shackle Straps Break on a 20ft Tandem Axle Trailer and the Rear Axle Slides the Tires
    One of the most common causes for shackle straps to break is over-tightening of the shackle bolts. If the shackle bolts are too tight, the shackle straps are not able to move with the suspension. This causes binding and it can bend or even brake the shackle straps, bolts and hangers. The sliding that you are experiencing on the rear axle is common for tandem and triple axle trailers and it is usually called scrubbing. The rear axle scrubs because trailer axles are not steering axles,...
    view full answer...
  • How to Tighten Shakle Links on a Utility Trailer Suspension
    There usually is not a bushing in the upper bolt on the shackle links. When tightening the bolts on the shackle link you will want to get them tight but you do not want to over tighten them. Being tight will not keep the suspension from working properly but over tightening things could cause problems. The weight of the trailer and the suspension will allow the shackle links to move properly. When reinstalling the nuts on the shackle bolts make sure that you use locking style nuts so that...
    view full answer...
  • Torque Specs for Redline Shackle Bolt with Locknut
    There actually is not a specific torque rating for shackle bolts like the Redline # 166081 that you referenced. You just want to make sure that the bolt is long enough so that when installed you have at least 2 threads protruding from the nut. This particular bolt measures 3 inches in length and the locknut is included. I have attached a short video demonstration that you can also check out.
    view full answer...
  • Can Replacement Shackle Bolt Have Longer Thread Length
    I do understand your concern with the potential of a slightly longer thread length on the Shackle Bolt # 166081 causing the shackle strap to sit right on the threads. The fact is though that the shackle positioned there as opposed to the unthreaded shank is not going to cause much of a difference, if any. The shackle straps should not wear down any quicker because of this. As long as the bolt's overall length is correct then this will work perfectly for your trailer.
    view full answer...
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  • How Is the Shackle Bolt with Locknut for Double-Eye Springs 166081 Measured
    The length of the Shackle Bolt with Locknut for Double-Eye Springs part # 166081 does not include the bolt head, just the shaft. I have attached a photo below.
    view full answer...
    Image 1 for
  • Torque Spec for 9/16" x 3" Long Bolt for Suspension
    There is not a specific torque requirement for bolts like the Shackle Bolt # 166081. You'll want to make sure that you're using a lock nut and ensure that the bolts you use are long enough so that when installed you will have at least 2 threads protruding that lock nut.
    view full answer...
  • Length of Redline # 166081 Suspension Shackle Bolt
    According to Redline, the # 166081 bolts are 3.1 inches long.
    view full answer...
  • Replacement Shackle Strap and Bolts for 2002 Carry-On Trailer
    You should get the Replacement Shackle Strap - 2-5/8" Long # 115052 along with the Shackle Bolt with Locknut for Double-Eye Springs - 3" Long # 166081. These will work well for your 2002 Carry-On Trailer with 2,000 lb axle.
    view full answer...
  • 9/16 inch Diameter Shackle Bolt Longer than 3 inches Availability
    We have the # 166079 which is a 9/16 inch diameter shackle bolt like you need that measures 3-1/2 inches in length.
    view full answer...
  • Do the Equalizers in Tandem-Axle Trailer Hanger Kit # APT5 Come with Bushings in Place
    Yes, the equalizers included in the referenced Tandem-Axle Trailer Hanger Kit # APT5 do come with nylon shackle bolt bushings already in place. These accept 9/16-inch diameter shackle bolts such as # 166081. I have linked two articles concerning trailer suspension that may be useful to you.
    view full answer...
  • Recommended Torque Specs for 9/16 and 1/2 Inch Trailer Suspension Hardware
    If you will be using 9/16 inch fasteners then torque them down to 110-114 foot pounds. If using 1/2 inch torque them to 76-78 foot pounds. You can find all sorts of different torque specs for the same size bolts or nuts and they will all be around these same figures. If you use Loctite use the blue kind, such as # LT37643, which will allow you to remove parts using hand tools. The red kind is going to be too strong. Also make sure the Loctite only goes on the threads and on any part that...
    view full answer...
  • How to Determine the Correct Leaf Spring Replacements for a 1975 Rolco Tandem Axle Boat Trailer
    It may be possible that your leaf springs flattened out from 27 inches. The 27 inch leaf springs we carry for 3,500 pound axles is # SP-210275. The bolt with locknut you need is # 166081.
    view full answer...
    Image 1 for
  • Torque Spec For Leaf Spring Shackle Bolts
    There is no specific torque rating for shackle bolts. You'll want to ensure that the bolts you use are long enough so that when installed you will have at least 2 threads protruding from the nut. Make sure that the bolt you're using has a lock nut, like part # 166081. If the bolt you are using has knurls at the bolt head, tighten the bolt down until the knurls go through the shackle link or hanger and the bolt head is flush. Then back off the nut slightly so that all of the components are...
    view full answer...
  • Availability of Trailer Suspension Shackles that are 3-1/2 inches Long
    We only have the # TRSL350 for a shackle that is 3-1/2 inches long from hole center to hole center. Typically these don't wear out as quickly as you described. Are you tightening the shackle bolts really tight which is causing added friction possibly? There is no specific torque rating for shackle bolts. You'll want to ensure that the bolts you use are long enough so that when installed you will have at least 2 threads protruding from the nut. Make sure that the bolt you're using has...
    view full answer...
    Image 1 for
  • 3-Leaf Double-Eye Spring for 2,000-lb Trailer Axles Shackle Bolt Diameter
    The 3-Leaf Double-Eye Spring for 2,000-lb Trailer Axles - 20-3/8" Long part # SP-169275 takes a 9/16" diameter shackle bolt like part # 166081. The trailer's weight rating is determined by the two axle capacities so one axle would not need to be rated to support the whole load if it's a tandem axle trailer. The capacities would be split up. If your boat is gear, fuel, and trailer is around 3,200 lbs I recommend to go with the 2-2,000 lb axles and 1,000 lb leaf springs because if not your...
    view full answer...
  • AL-KO 5200 lb Axle Mounting Bolt Size
    The U-Bolt Kit for Mounting 5,200-lb to 7,000-lb, Round Trailer Axles - 7-1/4" Long U-Bolts # APUBR-9 are 9/16 inch diameter. These hold the axle to the leaf springs. The bolts that hold the springs to the frame are also 9/16 inches and # 166081.
    view full answer...
  • Recommended Leaf Spring Bushings and Shackle Bolt with Locknut
    I recommend using the Never Fail Bushings - 9/16" Inner Diameter, 11/16" Outer Diameter - 1-3/4" - Qty 14 # LC279685. For 1-3/4 inch springs you will want the Shackle Bolt with Locknut for Double-Eye Springs - 3" Long # 166081. There is no specific torque rating for shackle bolts, you simply want to ensure they are long enough so you have at least 2 thread protruding from the bolt. You want to tighten the bolt until the knurls go through the shackle link or hanger and the bolt head is...
    view full answer...
  • Torque Specs for Axle Spindle Nut, Suspension Hanger Bolts, and Lug Nuts for Trailer
    It looks like you might be asking about a few different torque specs so I'll address all of them separately. For a trailer axle spindle nut like part # 165686 you will need to run the spindle nut down until there is no more side-to-side play in the hub and then back it off to the next notch so you can secure the cotter pin, like part # 165649, through the spindle. When it comes to hanger bolts like the Redline # 166081 there isn't a specific torque rating either as you just need to make...
    view full answer...
    Image 1 for
  • Comparing Wet and Dry Shackle Bolt Strength Rating
    A wet shackle bolt like the Redline # 126B2, the type that is hollow with a grease zerk fitting for lubrication, is just as strong as the dry (solid) type like # 166081. Neither variety of this part actually carries a weight capacity rating since the trailer weight is distributed across many of them.
    view full answer...
  • Availability of Wet Equalizer Bolts for a Joyrider Equalizer on a Prowler Trailer
    We do offer the wet shackle bolts you will need. The are the Wet Equalizer Bolt with Locknut and Grease Zerk, part # 126B2.
    view full answer...
  • How to Determine Axle Placement on a Custom 5 x 9 ATV and Motorcycle Trailer
    When determining the axle placement on a trailer, an important factor to consider is the tongue weight. You want the tongue weight of the trailer to be approximately 10 percent of the gross trailer weight. Moving the axle rearward will increase the tongue weight of the trailer. A heavy tongue weight could cause issues with traction and sway when towing, but that is not as much of a concern on smaller trailers than it is on larger travel trailers or enclosed trailers. First, we want to...
    view full answer...
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  • Shackle Bolt Recommendation for the CE Smith Front Hanger Bracket # CE14016G
    The diameter of the holes that are used for installing leaf springs is 9/16 of an inch. A bolt like the part # 166081 would work as it is 3 inches long and the bracket is 2-1/4 inches wide.
    view full answer...
  • Replacement Shackle Strap Recommendation that is 3-1/2 inches Long
    Your question came in blank, but based on the picture you submitted it looks like you are in need a replacement shackle strap that is 3-1/2 inches in length. For that you would want the Shackle Strap # TRSL225. This strap is 3-1/2 inches long like what you have pictured with the hole measurements 2-1/4 inches on center. For a new shackle bolt you would want the Shackle Bolt part # 166081.
    view full answer...
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