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  1. Boat Trailer Parts
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  3. Roller and Bunk Parts
  4. U-Bolts
  5. 3 Inch Long
  6. Zinc-Plated Steel
Trailer Square U-Bolts (Qty 2), 3-1/8" x 3" x 7/16"

Trailer Square U-Bolts (Qty 2), 3-1/8" x 3" x 7/16"

Item # 7163183UB
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Trailer Square U-Bolts Qty 2 3-1/8 Inch X 3 Inch X 7/16 Inch
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  • Reviews (35)
  • Q & A (0)
  • Videos (1)
  • Photos
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Redline Boat Trailer Parts - 7163183UB

  • Roller and Bunk Parts
  • U-Bolts
  • 3 Inch Long
  • Zinc-Plated Steel
  • 3-1/8 Inch Wide
  • 7/16 Inch Diameter
  • Redline

Trailer U-bolts ideal for boat, snowmobile, and standard utility trailers.

  • Zinc Plated to resist corrosion
  • Square bend simplifies attachment of hardware to square trailer frames
  • Dimensions:
    • A: 3-1/8"
    • D: 7/16"
    • L: 3"

cargo control display

7163183UB Trailer Square U-Bolts (Qty 2), 3-1/8" x 3" x 7/16"

Video of Trailer Square U-Bolts (Qty 2), 3-1/8" x 3" x 7/16"

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

Video Transcript for Review of Redline Boat Trailer Parts - Trailer Square U Bolts With Hardware - 7163183UB

Hi, everybody. Andy here with And today, we're gonna take a brief look at these trailer square U-bolts. Now, these multipurpose U-bolts are intended for use on trailers to help secure brackets, mounts, and cargo on your trailer's frame. These are zinc plated to resist corrosion. And it includes everything that you see here.

You're gonna get two U-bolts, four washers, and four nylon lock nuts. The inside dimensions, let me pull out my ruler here. Looking at the length first, measuring that, those inside dimensions, we're sitting right at three inches long. And then looking at the width, we're sitting right at 3 1/8 inches wide. And the diameter is gonna be 7/16 of an inch.

And the threaded length is sitting right at, move my finger there, right at two inches. That's gonna conclude our brief look today. Again, I hope it was helpful for you. My name is Andy. Thank you for joining me..

Customer Reviews

Trailer Square U-Bolts (Qty 2), 3-1/8" x 3" x 7/16" - 7163183UB

Average Customer Rating:  4.9 out of 5 stars   (35 Customer Reviews)


Was very happy with all my dealings with etrailer. I received all parts in a timely manner. Great people to deal with.
Nice to have a good midwest dealer.


These bolts were used on a 2x3 square steel tube to hold casters. The extra 1/8" in width made installation a breeze and the bolts themselves are well made. Mounting hardware is a big plus with self locking nuts included.


Great Service and value! Company followed up after delivery to make sure order was as expected. Thats customer service!!
Replacement parts for my trailer fit as advertised and arrived in a few days.
I highly recommend etrailer if you want customer satisfaction.


The parts showed up flawlessly and all worked out well!


Exactly what I needed. Great quality parts for rebuilding my bunk hardware.


Just what I needed


Received parts far quicker than I was expecting. The worked great and fit just like the old ones. Will use again.


Never had ordered from etrailer before......excellent service!
Ordered the parts Monday arrived Wednesday.
Great service, will order from them again.


Got just what I needed at a fair price. Got parts for my boat trailer.


Great customer service, fast shipping. I love the free shipping on $100 or more !! My new go to place for all my trailer needs, thanks


Easy ordering on the website, quick delivery, and good follow-up, making sure all was good with my order.

Thanks !


Worked great for mounting ammunition tool box to ROPS bar on Kubota BX 2350 tractor


Awesome support while ordering the parts. Everything fit perfectly. Shipping was very fast.

Everything is working fine.
J W - 10/10/2017


Finally found them, should've checked etrailer first.


Second set of these I've ordered. Perfect fit and size for my application over 3"x2" square steel tubing. Can't beat the quality!


Exactly what I needed


Excellent quality replacement from my 18 year old originals that needed to be replaced.


good quality


Fit perfectly

Still fitting fine.
Richard - 02/23/2020


Product received as expected. Great service. will definitely use again.


Great servive and very quick delivery. Price was very fair. I will buy again if the need arises.


Part came just as stated, installed and ready. Would buy again from etralier!


EXellent product...everything was exactly as advertised and shipping was quick


as described good quality


Just revived my order today.So far so good.Everything looks great.

Show More Reviews

See what our Experts say about this Redline Boat Trailer Parts

  • How Many U-Bolts Come with the Trailer Square U-Bolts (Qty 2) # 7163183UB
    The Trailer Square U-Bolts (Qty 2) # 7163183UB that you referenced contains 2 u-bolts per order.
    view full answer...
  • Replacement Hardware for Hitch for 1994 Toyota Camry
    The best way to insure you have the proper hardware is to order a Replacement Hardware Kit, it comes with all the nuts, bolts and other hardware that originally came with the hitch. Use part # RHK and enter in the manufacturer and model number of the hitch and we can send you all the hardware that should be used to install the hitch.
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  • Availability of U-Bolts to Fit Around a 4-Inch RV Bumper
    The only U-bolts we sell that are designed to fit around a 4 inch bumper are meant to be used with a spare tire carrier like part # TR-1. The replacement U-bolts are part # TR-2200. These are meant to secure a spare tire carrier only, and would not be recommended for a bike rack or a bumper mounted receiver. If you could tell me what you were needing the U-bolts for, I might be able to find you a more suitable replacement.
    view full answer...
  • How to Secure Removable Cargo Box from Rola Tilting Enclosed Cargo Carrier
    The Rola Tilting Enclosed Cargo Carrier # 59109 that you referenced does come with locks to secure both the lid of the cargo box and to secure the box to the tray portion (using the same key) but it does not have a built-in facility to allow the box portion to be locked to a stationary object such as a tree at your campsite. I checked with my contact at Rola and confirmed that no optional lock kit is offered for this item for that particular application. However, it is certainly possible...
    view full answer...
  • Would the Single Axle Trailer Fenders # PF11X35W-2 fit on an EZ Loader Trailer with 15 in Wheels
    The Single Axle Trailer Fenders # PF11X35W-2 you referenced are designed to fit 13-15 inch wheels so it should fit your wheels. The fenders are 11-5/16 inches wide by 45 inches long by 13 inches tall, you will need to compare those dimensions to your setup to see if they will be compatible. I also attached a picture that shows how the installation hardware installs on a trailer for you to check out. We offer two suitable u-bolts that might work for you, depending on the height of your...
    view full answer...
    Image 1 for
  • Mounting Instructions for Redline # PF11X35W-2 Fenders
    I do not have instructions, but I can explain how the fender brackets are used. The mounting brackets slide into the underside of the step on either side of the fender with the open end of the bracket facing downward. The fender secures to the bracket by running a bolt (not included) through existing holes in the fender into holes in the bracket. The flat top edge of the bracket attaches to the underside of the trailer frame using U-bolts that are not included. We offer two suitable u-bolts...
    view full answer...
    Image 1 for
  • Recommended U-bolts and Brackets for Boat Trailer Bunk Boards
    I recommend the Trailer Square U-Bolts (Qty 2), 3-1/8" x 3" x 7/16" # 7163183UB to go with the CE Smith Bolster and Swivel Bracket Assemblies - Galvanized Steel - 9" - Qty 4 # CE10000G-4. This will allow you to mount them to your 3x3 inch square tube trailer. For your bunk boards, I recommend the Fulton Marine Grade Carpeting, 12" Wide x 144" Long - Black # FCR8012 to cover your bunk boards. Make sure to use pressure treated lumber and attach with corrosion resistant hardware and stainless...
    view full answer...
  • Do Roller Bunk Brackets DL21742 Require 7/16" U-Bolts?
    The Boat Trailer Roller Bunk Brackets # DL21742 do require 7/16" U-bolts such as # 7163183UB. The bunk brackets are designed to be used with Roller Bunks # DL21740 or # DL21741.
    view full answer...
  • Recommended Roof Rack For 2007 Toyota Prius To Carry Plywood Mounted Solar Panel
    We do not have roof racks with holes in them as you mentioned but the best option I can recommend is to install a roof rack with a square crossbar like the Thule Traverse roof rack. This roof rack has 43-inch square steel crossbars and a custom fit kit for your 2007 Prius. to order this roof rack you will need part # TH712100, part # TH710501, and part # TH145181. I then recommend using U-bolts similar to part # 7163183UB to secure the plywood on the roof rack. These U-bolts come with...
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  • Looking for 6 Galvanized U-Bolts that are 3 Inches Square with 7/16 or 1/2 Inch Diameter
    We have a few different options for you to choose from. The CE Smith U-Bolt, # CE15252A, is zinc-plated and it is 3 inches long x 3-1/8 inches wide x 7/16 inch diameter. This u-bolt was designed to fit around 3 inch trailer frames. We also offer this u-bolt in a set of 2 as part # 7163183UB and with a stainless steel finish which is part # CE15502A. I have attached links to each of these parts below. We do not carry any square u-bolts that are 3 inches wide because they would be more...
    view full answer...
  • U-Bolts to Attach Bunk Brackets to Trailer with 3 inch Frame
    For a 3 inch trailer frame like you said you have we have the U-bolts part # 7163183UB which will work great for attaching roller bunk brackets like the part # CE10000G-4. The inside portion of the U-bolt is 3-1/8 inches wide by 3 inches long.
    view full answer...

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Info for this part was:

Employee Patrick B
Expert Research:
Patrick B
Employee Jameson C
Expert Research:
Jameson C
Employee Laura H
Updated by:
Laura H
Employee Andy C
Installed by:
Andy C

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