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

Trailer Square U-Bolts (Qty 2), 3-1/8" x 4" x 7/16"

Item # 7163184UB
lowest price pledge
Our Price: $23.94
Boat Trailer Parts
Orders above $99 qualify for Free Shipping
Shipping Weight: 1.12 lbs
In Stock
Trailer Square U-Bolts Qty 2 3-1/8 Inch x 4 Inch x 7/16 Inch
zoom in icon
slider vertical icon
zoom out icon
Comment field cannot be left empty.
Name field cannot be left empty.

Thank you! Your comment has been submitted successfully. You should be able to view your question/comment here within a few days.

Error submitting comment. Please try again momentarily.

Product Images

Customer Photos

Need help with installation?
Locate installers near me
1-800-940-8924 to order Redline boat trailer parts part number 7163184UB or order online at Free expert support on all Redline products. Guaranteed Lowest Price and Fastest Shipping for Trailer Square U-Bolts (Qty 2), 3-1/8" x 4" x 7/16". Boat Trailer Parts reviews from real customers.
  • All Info
  • Reviews (35)
  • Q & A (0)
  • Photos
  • Why etrailer?

Redline Boat Trailer Parts - 7163184UB

  • Roller and Bunk Parts
  • U-Bolts
  • 4 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: 4"

cargo control display

7163184UB Trailer Square U-Bolts (Qty 2), 3-1/8" x 4" x 7/16"

Customer Reviews

Trailer Square U-Bolts (Qty 2), 3-1/8" x 4" x 7/16" - 7163184UB

Average Customer Rating:  4.8 out of 5 stars   (35 Customer Reviews)


Parts fit well, I have use ETrailer in the past, they always deliver.


Before and after pics

Everything is perfect.
Greg - 05/29/2019


Wish these were stainless however they are tge correct part to hold down a section of trailer. Being a bit thicker would be longer lasting. Now to receive the correct shackle.


Everything came in as advertised. Purchased CE Smith bolsters, u-brackets, lag screws and carpet. Added two bunk boards to my Lowe trailer (Karavan). Only had two boards and I wanted extra to support the weight of the boat. Everything assembled easily. My boat loads easier and trailers better. Plus I have the piece of mind of having 4 boards vs 2.


After several attempts at finding the right clamps for my Surco cargo basket, we have a winner! The ones that Surco recommended for my Explorer did not work and they did not have alternatives. Amy was a tremendous help and even had the U bolts sent to her to verify the size before I ordered it. She also found the right size of shackle strap I needed to make this work for me! Thanks Amy and etrailer!!


I received my order promptly and all the nuts and washers were packaged with each item. Customer service was excellent and I will tell all my friends. I haven't installed the items purchased but don't expect any problems due to their excellent quality. I highly recommend


The product I needed was not a common part. But Etrailer had it in stock, at a reasonable price. Product was shipped immediately with the standard shipping selected. Great vendor... would do business with them again, without hesitation!


Parts were as advertised and were a perfect replacement for the parts on my trailer. I was pleased to find the parts came with washers and nylon insert lock nuts.


new hardware and fresh rubber for a boat trailer holding a very old boat. parts arrived early and fit like OEM. If I need trailer parts ever again I will purchase them here.


I found what I needed on this site. Definitely will be returning for any other trailer parts.


Parts were exactly what I needed, time will tell how they hold up with corrosion. I probably should of used 2x6 instead of the 2x4 bunks, but there was nothing wrong with these bunks. Time will tell how they hold up.


The U bolts shackle straps I ordered worked great and were high quality parts. I received my order faster than was promised. I will defiantly use these guys again.


Fit perfect and was good replacement for a rotted bolt.


Not much to say - great quality parts at a good price. Ordered this with other items for a nice one stop shopping experience.


items were of great quality and service was fast and well packed.


Super fast shipping, and items were exactly as stated. Great seller. Highly recommend.


They should work when I get the chance to install them. The weather needs to get better so I can install them outside.


Sturdy, and the right fit for my trailers configuration.


The items ordered were just as described and arrived in a very timely manner. Very pleased to order from eTrailer and will do so again as needed.


Excellently constructed pieces. Service was excellent.


Received what I ordered in a timely manner, product is as advertised and exactly what I needed.


Exactly as described. Thanks


Simply Flawless :
Ordering , communication
,shipping speed , quality and fit of product.


Worked well


perfect fit ,only probably was package open and parts spilled out but all there

Show More Reviews

Ask the Experts about this Redline Boat Trailer Parts

  • Grade of Steel Used in the U-Bolt Kit # 7163184UB
    The Redline U-bolts we carry like the part # 7163184UB are Grade 5.
    view full answer...
  • Could U-Bolt # 7163184UB Fit Over 2x4 or 2x6
    The inner width of the U-bolt part # 7163184UB that you referenced is 3-1/8 inches. Since 2x4 boards are actually 3.5 inches long this would not fit the board width-wise. Length wise it would fit both sizes. For width you'd instead need the part # CE15260A.
    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

Do you have a question about this Boat Trailer Part?

  • Why

    At we guarantee:
  • Highest quality boat trailer parts for the best price.

    Our Lowest Price Pledge ensures you will never overpay for the parts you need.
  • Real product know-how.

    We make sure that the products we sell are what we say they are, and that they work the way they are supposed to work. Get real advice from a real person who has the knowledge and expertise needed to solve your problem.
  • Most detailed, accurate boat trailer part information available.

    Because we take providing accurate product information seriously, we take our own detailed product photos, demo videos and installation videos, as well as verify measurements, instructions, and vehicle fit information.
  • Installations, made easy.

    We love helping people and have the most highly-trained customer service, hands-on experience, step by step videos and installation instructions.
  • Fast shipping.

    Your order is automatically routed to get out of our warehouse and to your door as quickly as possible. Receive free shipping on orders over $99.
  • Personalized service for life.

    We provide one-on-one, personalized service from the ordering process through the life of your product.
  • Trusted since 1946.

    We've been serving customers since our parts store first opened in 1946 and continue to be recognized by our customers, our vendors and third parties for exceptional service.
  • Returns Policy

    Need to return an item? No problem. Please read our Returns Policy for more information.

Info for this part was:

Employee Jameson C
Expert Research:
Jameson C
Employee Laura H
Updated by:
Laura H

At we provide the best information available about the products we sell. We take the quality of our information seriously so that you can get the right part the first time. Let us know if anything is missing or if you have any questions.