Looking for the best trailer leaf spring U-bolt kits? We’ve curated a list of 10 top-rated options to help you find the perfect fit for your trailer.
Trailer leaf spring U-bolt kits are essential for keeping your trailer safe and reliable. Whether you’re hauling cargo, boats, or heavy loads, the right kit ensures a smooth ride and long-lasting performance.
Choosing the best kit can feel overwhelming, but we’ve done the work for you. Our guide highlights top-rated options that fit various axle sizes and trailer types. You’ll find kits that are easy to install and built to last.
Upgrade your trailer with confidence. Stay safe on the road. Find the perfect fit today.
List of Top 10 Trailer Leaf Spring U-Bolt Kits
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TRAILER SUPPLIES Trailer Leaf Spring and U-Bolt Kit – (2) 24-5/8″ 4-Leaf Slipper Springs + 2000 lbs U-Bolt Mounting Kit – Fits 1-3/4″ Round Axles– for Utility, Boat, and Cargo Trailers |
This trailer leaf spring and U-bolt kit is perfect for anyone with a utility, boat, or cargo trailer needing a reliable suspension upgrade. It’s easy to install and built to last, making it ideal for light-duty trailers with 2,000 lb axles. |
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SPARKWHIZ Trailer U Bolt Kit, 5-1/2 inch U Bolt for 3,500 lb Trailer Axle, 2-3/8″ Round Axle, 1/2” Diameter, 2″ Thread Pitch |
This is perfect for trailer owners who need a strong, easy-fit U bolt kit for a 3,500 lb round axle. It is also a great choice for people who want safe towing, rust resistance, and fast install. |
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Square U-Bolt Kit for Boat Trailer Mounting Axle Leaf Springs Zinc(4 U-Bolt + 2 Plate), Heavy Duty Square U-Bolts with Nuts and Frame Plate for Trailer Automobiles Trailer, 2″ W x 5″ L |
This kit is for boat owners. It helps you fix your trailer axle. It is strong and fits well. |
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New Trailer U Bolt Kit, Trailer Leaf Spring U Bolts, for 5200-7000lbs 3″ Round Axle, 7” Long U-Bolts, 1/2” Diameter, 3” Wide U Bolts-20080 |
This new kit is for you. It fits your trailer well. These u-bolts are strong. They fix your axle fast. Use them for a safe ride. Your boat or cart will stay secure. Buy this set to save time. |
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Replacement for SW5 5 Pieces Trailer Leaf Spring, 6000LB Tandem Trailer Axle Suspension Kit with 3000lb Capacity Double Eyes Leaf Springs, 2* U-Bolt and Hanger Kit |
This trailer leaf spring kit is perfect for anyone who needs to replace or upgrade their tandem trailer axle suspension. It’s ideal for trailers with a 5200lbs-6000lbs axle, offering reliable performance and easy installation. |
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Trailer U Bolt Kit for 3500 lbs Trailer Axle, 2-3/8″ Round Axle, 6-1/4″ Long, 1/2” Diameter, Trailer Leaf Spring U Bolt Kit by MCCKLE (2 Pack) |
This trailer U-bolt kit is perfect for anyone who needs a reliable and sturdy solution for their 3500 lbs trailer axle. It’s ideal for DIY enthusiasts and trailer owners looking for easy installation and long-lasting performance. |
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Racewill U Bolt Kit for Boat Trailer Axle Leaf Springs, U Bolts 2 inch Wide, for 2×2 Axle – 4 3/4″ Long |
This U Bolt Kit is perfect for boat owners who need a strong and secure solution for their trailer axle leaf springs. It’s ideal for 2×2 axles and works great in saltwater or freshwater environments. |
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Racewill Square U Bolt Kit for Boat Trailer Axle Leaf Springs, Trailer Leaf Spring U Bolts, for 2×2 Axle – 5 1/4″ Long |
This Racewill Square U Bolt Kit is perfect for boat owners who need a strong and secure solution for their trailer axle leaf springs. It’s ideal for 2×2 axles and works great in saltwater or freshwater environments. |
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Lonffery 25-1/4 Leaf Spring with 5-1/2 U Bolts Trailer Axle Suspension Kit Fit for 3500lb Round Axle (Shackle Strap+Hanger+Leaf Spring+U-Bolt) |
This Lonffery Trailer Axle Suspension Kit is perfect for anyone who needs to upgrade or repair their 3,500lb round axle trailer. It’s easy to install and comes with everything you need for a smooth, reliable ride. |
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SPARKWHIZ Trailer U Bolt Kit 7 inch for 5,200-7,000 lb Trailer Axle, 3″ Round Axle, 1/2” Diameter, 2″ Thread Pitch, 2 Pack |
This SPARKWHIZ Trailer U Bolt Kit is perfect for anyone with a 5,200-7,000 lb trailer needing strong, rust-resistant parts. It’s easy to install and improves braking performance, making it ideal for DIYers or professionals. |
Detailed Reviews
Discover the top 10 Trailer Leaf Spring U-Bolt Kits carefully selected for performance, durability, and value. Whether you need heavy-duty strength or easy installation, this guide has you covered. Find the perfect kit to keep your trailer safe and smooth on every journey.
1. TRAILER SUPPLIES Trailer Leaf Spring and U-Bolt Kit – (2) 24-5/8″ 4-Leaf Slipper Springs + 2000 lbs U-Bolt Mounting Kit – Fits 1-3/4″ Round Axles– for Utility, Boat, and Cargo Trailers

Upgrade your trailer today. This kit fits cargo and boat trailers.
The springs carry heavy loads. These u-bolts fit round axles. Use this kit for safety.
Install the parts with ease. Your trailer will ride smooth.
| Pros | Cons |
|---|---|
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Perfect For:
This trailer leaf spring and U-bolt kit is perfect for anyone with a utility, boat, or cargo trailer needing a reliable suspension upgrade. It’s easy to install and built to last, making it ideal for light-duty trailers with 2,000 lb axles.
Ready to Purchase?
2. SPARKWHIZ Trailer U Bolt Kit, 5-1/2 inch U Bolt for 3,500 lb Trailer Axle, 2-3/8″ Round Axle, 1/2” Diameter, 2″ Thread Pitch

The SPARKWHIZ Trailer U Bolt Kit fits a 3,500 lb round axle. It is made for a 2-3/8″ axle beam. It helps keep parts tight and secure.
It comes with 4 U bolts, 8 hex nuts, and 2 tie plates. The steel build is strong and long lasting. It also helps fight rust and corrosion.
This kit can help your braking system work better. It is also easy to install.
| Pros | Cons |
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Perfect For:
This is perfect for trailer owners who need a strong, easy-fit U bolt kit for a 3,500 lb round axle. It is also a great choice for people who want safe towing, rust resistance, and fast install.
Ready to Purchase?
3. Square U-Bolt Kit for Boat Trailer Mounting Axle Leaf Springs Zinc(4 U-Bolt + 2 Plate), Heavy Duty Square U-Bolts with Nuts and Frame Plate for Trailer Automobiles Trailer, 2″ W x 5″ L

This U-bolt kit fits 2×2 axles. It is heavy duty.
Each steel bolt holds 150 lbs. The zinc coat stops rust. Use it for boats and trailers.
The kit has four bolts. It has plates and nuts. All parts are strong.
| Pros | Cons |
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Perfect For:
This kit is for boat owners. It helps you fix your trailer axle. It is strong and fits well.
Ready to Purchase?
4. New Trailer U Bolt Kit, Trailer Leaf Spring U Bolts, for 5200-7000lbs 3″ Round Axle, 7” Long U-Bolts, 1/2” Diameter, 3” Wide U Bolts-20080

This trailer U bolt kit is built tough. It fits 5200-7000lbs round axles with a 3-inch diameter. Perfect for heavy-duty trailers.
The kit includes 4 U bolts, 8 hex nuts, and 2 tie plates. All parts are made of durable steel. They fit perfectly with no loose ends.
Installation is quick and easy. No special tools needed. Replace broken parts in just minutes.
| Pros | Cons |
|---|---|
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Perfect For:
This new kit is for you. It fits your trailer well. These u-bolts are strong. They fix your axle fast. Use them for a safe ride. Your boat or cart will stay secure. Buy this set to save time.
Ready to Purchase?
5. Replacement for SW5 5 Pieces Trailer Leaf Spring, 6000LB Tandem Trailer Axle Suspension Kit with 3000lb Capacity Double Eyes Leaf Springs, 2* U-Bolt and Hanger Kit

Upgrade your trailer with this 5-piece leaf spring kit. It’s built for 6000LB tandem axles and handles 3000LB per spring. Perfect for heavy-duty use.
Made from heavy-duty carbon steel, these springs are rust-resistant and long-lasting. The kit includes U-bolts, hangers, and shackle straps for easy installation. Everything you need is included.
Need help? Our after-sales service is here for you. Contact us anytime with questions. Thanks for choosing us!
| Pros | Cons |
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Perfect For:
This trailer leaf spring kit is perfect for anyone who needs to replace or upgrade their tandem trailer axle suspension. It’s ideal for trailers with a 5200lbs-6000lbs axle, offering reliable performance and easy installation.
Ready to Purchase?
6. Trailer U Bolt Kit for 3500 lbs Trailer Axle, 2-3/8″ Round Axle, 6-1/4″ Long, 1/2” Diameter, Trailer Leaf Spring U Bolt Kit by MCCKLE (2 Pack)

This U bolt kit fits a 3500 lbs trailer axle. It works with a 2-3/8″ round axle for a strong hold.
The steel is durable and rust-resistant. Installation is quick and simple. The kit includes all parts needed for a secure fit.
| Pros | Cons |
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Perfect For:
This trailer U-bolt kit is perfect for anyone who needs a reliable and sturdy solution for their 3500 lbs trailer axle. It’s ideal for DIY enthusiasts and trailer owners looking for easy installation and long-lasting performance.
Ready to Purchase?
7. Racewill U Bolt Kit for Boat Trailer Axle Leaf Springs, U Bolts 2 inch Wide, for 2×2 Axle – 4 3/4″ Long

The Racewill U Bolt Kit is strong and secure. It’s made for boat trailer axle leaf springs. The heavy-duty steel ensures maximum durability.
It fits 2×2 axles perfectly. The zinc-coated surface resists corrosion in saltwater or freshwater.
The kit includes everything you need. It has mounting plates, U-bolts, nuts, and washers. It’s fully adjustable for your needs.
| Pros | Cons |
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Perfect For:
This U Bolt Kit is perfect for boat owners who need a strong and secure solution for their trailer axle leaf springs. It’s ideal for 2×2 axles and works great in saltwater or freshwater environments.
Ready to Purchase?
8. Racewill Square U Bolt Kit for Boat Trailer Axle Leaf Springs, Trailer Leaf Spring U Bolts, for 2×2 Axle – 5 1/4″ Long

The Racewill Square U Bolt Kit is made for a 2×2 boat trailer axle. It has a strong steel build. It helps hold parts tight and safe.
Each U bolt is zinc-coated for rust resistance. It works well in fresh water and salt water. The fit is easy to adjust.
This kit includes mounting plates, U bolts, nuts, flat washers, and lock washers. It gives you the parts you need for a secure install.
| Pros | Cons |
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Perfect For:
This Racewill Square U Bolt Kit is perfect for boat owners who need a strong and secure solution for their trailer axle leaf springs. It’s ideal for 2×2 axles and works great in saltwater or freshwater environments.
Ready to Purchase?
9. Lonffery 25-1/4 Leaf Spring with 5-1/2 U Bolts Trailer Axle Suspension Kit Fit for 3500lb Round Axle (Shackle Strap+Hanger+Leaf Spring+U-Bolt)

The Lonffery 25-1/4 Leaf Spring with 5-1/2 U Bolts Trailer Axle Suspension Kit is perfect for your 3500lb round axle. It includes everything you need for a smooth and reliable suspension system.
This kit has 2 leaf springs, 4 U-bolts, shackle straps, hangers, and all necessary hardware. It fits 2-3/8″ round axles and supports 1750lbs per spring.
Installation is quick and easy, thanks to its simple design. It’s built to last and ensures stable trailer performance.
| Pros | Cons |
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Perfect For:
This Lonffery Trailer Axle Suspension Kit is perfect for anyone who needs to upgrade or repair their 3,500lb round axle trailer. It’s easy to install and comes with everything you need for a smooth, reliable ride.
Ready to Purchase?
10. SPARKWHIZ Trailer U Bolt Kit 7 inch for 5,200-7,000 lb Trailer Axle, 3″ Round Axle, 1/2” Diameter, 2″ Thread Pitch, 2 Pack

The SPARKWHIZ Trailer U Bolt Kit is built tough. It fits 5,200-7,000 lb trailer axles with a 3-inch round beam. Each kit includes 8 U bolts, 16 nuts, and 4 tie plates.
This kit is made of durable steel. It resists rust and corrosion, ensuring long-lasting use. It also boosts your braking system’s performance.
Installation is quick and easy. The kit works perfectly with 1-3/4″ leaf springs. It’s a reliable choice for your trailer needs.
| Pros | Cons |
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Perfect For:
This SPARKWHIZ Trailer U Bolt Kit is perfect for anyone with a 5,200-7,000 lb trailer needing strong, rust-resistant parts. It’s easy to install and improves braking performance, making it ideal for DIYers or professionals.
Ready to Purchase?
Buying Guide
Trailer leaf spring U-bolt kits keep your trailer safe and reliable. They ensure a smooth ride and long-lasting performance. Choosing the right kit is easy with our guide.
Factors to Consider When Buying Trailer Leaf Spring U-Bolt Kits:
– Axle Size: Match the kit to your trailer’s axle size (e.g., 2×2, 3-inch round). A perfect fit ensures safety and stability.
– Weight Capacity: Check the kit’s weight rating (e.g., 3,500 lbs, 7,000 lbs). It must handle your trailer’s load without failing.
– Material Quality: Look for durable steel with rust-resistant coatings like zinc. This ensures longevity in all weather.
– Ease of Installation: Choose kits with clear instructions and included hardware. Quick installs save time and effort.
– Compatibility: Ensure the kit fits your trailer type (e.g., utility, boat, cargo). Compatibility avoids costly mistakes.
– Brand Reputation: Pick trusted brands known for quality and reliability. Good brands offer warranties and support.
– Price vs. Value: Compare prices and features. A higher price often means better durability and performance.
Upgrade your trailer with confidence. Stay safe on the road. Find the perfect fit today.