A solid U‑bolt is the backbone of any reliable headache rack, holding your gear steady when the road throws its worst. You’ll uncover why certain kits stand out—grade‑8 strength, corrosion‑resistant finishes, and perfectly sized tie plates that spread the load. The right choice can mean the difference between a secure load and a wobbling mess. Ready to see which seven kits earn a spot in your truck’s arsenal?
| Heavy Duty 20″ Square U-Bolt Kit with Tie Plates |
| Heavy‑Duty Pro | U‑Bolt Length: 20 in (square) | U‑Bolt Diameter / Thread Size: 5/8 in | Tie Component (Plate/Bar): Tie plates (size not listed) | VIEW LATEST PRICE | Read Our Analysis |
| 4-Pack Heavy Duty Square Bend U-Bolt Kit with Tie Bars |
| Versatile Pack | U‑Bolt Length: 20 in (square bend) | U‑Bolt Diameter / Thread Size: 5/8 in | Tie Component (Plate/Bar): 1‑1/8 × 6 in tie bars | VIEW LATEST PRICE | Read Our Analysis |
| Moroso 67300 U Bolts (Set of 4) |
| Compact Value | U‑Bolt Length: Not specified (standard size) | U‑Bolt Diameter / Thread Size: UN (standard) | Tie Component (Plate/Bar): Tie plate (standard) | VIEW LATEST PRICE | Read Our Analysis |
| Prime-Line U-Bolts 5/16‑18 X 1‑3/8 X 2‑1/2 (10 Pack) |
| Precision Fit | U‑Bolt Length: 2½ in (round bend) | U‑Bolt Diameter / Thread Size: 5/16‑18 | Tie Component (Plate/Bar): U‑bolt plate (included) | VIEW LATEST PRICE | Read Our Analysis |
| 18″ Square U-Bolt Kit with 1/2″ x 4-1/4″ Tie Bars (Grade 8) |
| Grade‑8 Strength | U‑Bolt Length: 18 in (square) | U‑Bolt Diameter / Thread Size: 5/8 in (Grade 8) | Tie Component (Plate/Bar): 1/2 × 4‑1/4 in tie bars | VIEW LATEST PRICE | Read Our Analysis |
| Rough Country 1/2″ Round Suspension U-Bolts (Set of 4) |
| Suspension Specialist | U‑Bolt Length: 6.75 in (round) | U‑Bolt Diameter / Thread Size: 1/2 in | Tie Component (Plate/Bar): No tie component (round style) | VIEW LATEST PRICE | Read Our Analysis |
| 16″ Square U-Bolt Kit with Tie Plates |
| Mid‑Size Champion | U‑Bolt Length: 16 in (square) | U‑Bolt Diameter / Thread Size: 5/8‑10 | Tie Component (Plate/Bar): 6 in tie plates | VIEW LATEST PRICE | Read Our Analysis |
More Details on Our Top Picks
Heavy Duty 20″ Square U-Bolt Kit with Tie Plates
The Heavy‑Duty 20‑inch Square U‑Bolt Kit with Tie Plates is the go‑to solution for anyone who needs rock‑solid, hassle‑free mounting of a headache rack on a heavy‑duty truck. You’ll appreciate the 20‑inch square design that matches standard rack dimensions, while the U‑bolts provide deep, secure penetration into the frame. The included tie plates distribute load evenly, preventing stress cracks and vibration. Made from hardened steel, the hardware resists rust and fatigue, even under heavy loads. Installation takes minutes: align the plates, insert the bolts, tighten with a wrench, and you’re ready for any cargo adventure. No wobble, no worries.
- U‑Bolt Length:20 in (square)
- U‑Bolt Diameter / Thread Size:5/8 in
- Tie Component (Plate/Bar):Tie plates (size not listed)
- Material / Finish:Heavy‑duty steel (finish not listed)
- Pack Quantity (U‑Bolt Sets):1 kit (unspecified count)
- Intended Application (Truck Chassis):Truck chassis / headache rack
- Additional Feature:5/8‑10 thread size
- Additional Feature:Zinc‑plated steel finish
- Additional Feature:4‑piece kit includes nuts
4-Pack Heavy Duty Square Bend U-Bolt Kit with Tie Bars
If you need a rugged, ready‑to‑install solution for securing your headache rack, the BGTLGIO 4‑Pack Square Bend U‑Bolt Kit delivers exactly that. Each set contains a 4 × 20‑inch square‑bend U‑bolt forged from alloy steel, zinc‑coated for corrosion resistance, and a 1‑1/8 × 6‑inch tie bar. The 5/8‑inch UNC thread and Grade 5 hardness give you reliable strength on any truck chassis. With four complete kits, you can mount multiple rack points or replace worn hardware without extra purchases. At 3.6 lb total, the kit stays lightweight yet tough, making installation quick and secure.
- U‑Bolt Length:20 in (square bend)
- U‑Bolt Diameter / Thread Size:5/8 in
- Tie Component (Plate/Bar):1‑1/8 × 6 in tie bars
- Material / Finish:Alloy steel, zinc‑plated
- Pack Quantity (U‑Bolt Sets):4 complete sets
- Intended Application (Truck Chassis):Truck chassis (universal joint)
- Additional Feature:Grade 5 steel hardness
- Additional Feature:1‑1/8 × 6 tie bars
- Additional Feature:3.6 lb total weight
Moroso 67300 U Bolts (Set of 4)
Truck owners who need a reliable, rust‑resistant connection for their headache racks will appreciate the Moroso 67300 set of four U‑bolts, which combine a sturdy alloy‑steel core with a black‑oxide finish that resists corrosion. You’ll find each bolt sized to fit standard rack brackets, featuring a right‑hand UN thread and Grade 2 hardness for solid holding power. The compact 7.19 × 5.44 × 1.13‑inch package weighs just 8.2 ounces, making storage easy. With a black finish that blends with most trucks, these bolts replace OEM part 67250 and come from a reputable Chinese manufacturer. Their Amazon ranking shows they’re a trusted replacement for axle U‑bolt kits.
- U‑Bolt Length:Not specified (standard size)
- U‑Bolt Diameter / Thread Size:UN (standard)
- Tie Component (Plate/Bar):Tie plate (standard)
- Material / Finish:Alloy steel, black oxide
- Pack Quantity (U‑Bolt Sets):4 per pack
- Intended Application (Truck Chassis):Automotive replacement (axle)
- Additional Feature:Black oxide coating
- Additional Feature:Grade 2 alloy steel
- Additional Feature:8.2 oz per kit
Prime-Line U-Bolts 5/16‑18 X 1‑3/8 X 2‑1/2 (10 Pack)
Because you need a reliable way to secure pipes, conduit, or cables on a head‑rack, Prime‑Line’s 5/16‑18 × 1‑3/8 × 2‑1/2 U‑bolts are the perfect fit. The zinc‑plated steel construction resists rust while the coarse UNC‑2A threads grip firmly. Each 10‑pack includes a U‑bolt plate and two nuts, so you can mount 1‑inch pipe or similar cylinders with pre‑drilled holes. The round‑bend head distributes load evenly, and the 1‑3/8‑inch width and 2‑1/2‑inch length give ample clearance for most truck head‑racks. At 1.48 lb total, they’re lightweight yet strong, earning a 4.7‑star rating from 106 reviewers.
- U‑Bolt Length:2½ in (round bend)
- U‑Bolt Diameter / Thread Size:5/16‑18
- Tie Component (Plate/Bar):U‑bolt plate (included)
- Material / Finish:Zinc‑plated steel
- Pack Quantity (U‑Bolt Sets):10 pieces (5 sets of 2)
- Intended Application (Truck Chassis):Pipe/conduit mounting (general)
- Additional Feature:Round‑bend head style
- Additional Feature:Zinc‑plated steel construction
- Additional Feature:1.48 lb package weight
18″ Square U-Bolt Kit with 1/2″ x 4-1/4″ Tie Bars (Grade 8)
The 18‑inch square U‑bolt kit with 1/2‑inch × 4‑1/4‑inch tie bars is the go‑to solution for anyone who needs a rock‑solid, adjustable connection between a truck body and chassis. You’ll get four hot‑dip‑galvanized, Grade 8 U‑bolts, eight hex nuts, eight lock washers, and four 5‑3/4‑inch‑wide tie bars. The 5/8‑inch diameter and 0.63‑inch groove fit most chassis, while the square heads resist rotation under load. With universal adjustability, you can secure boxes, racks, or custom bodies without drilling new holes. The kit weighs 15.82 lb, making installation sturdy yet manageable for any truck‑owner.
- U‑Bolt Length:18 in (square)
- U‑Bolt Diameter / Thread Size:5/8 in (Grade 8)
- Tie Component (Plate/Bar):1/2 × 4‑1/4 in tie bars
- Material / Finish:Hot‑dip galvanized steel
- Pack Quantity (U‑Bolt Sets):4 kits (4 U‑bolts each)
- Intended Application (Truck Chassis):Truck bodies & boxes to chassis
- Additional Feature:Hot‑dip galvanized finish
- Additional Feature:4‑piece kit includes lock washers
- Additional Feature:15.82 lb total weight
Rough Country 1/2″ Round Suspension U-Bolts (Set of 4)
If you need a rugged, corrosion‑resistant solution for worn suspension bolts, Rough Country’s 1/2‑inch round U‑bolts deliver exactly that. You’ll get a set of four heavy‑duty steel U‑bolts with an e‑coated black finish that fights rust for years. The 2.75‑inch width and 6.75‑inch length fit most custom racks, and the round style matches standard suspension brackets. Installation takes just two to three hours, and the bolts weigh 3.7 lb, making handling easy. Rough Country backs them with a limited lifetime replacement warranty, so you can trust they’ll stay solid under heavy loads.
- U‑Bolt Length:6.75 in (round)
- U‑Bolt Diameter / Thread Size:1/2 in
- Tie Component (Plate/Bar):No tie component (round style)
- Material / Finish:E‑coated black steel
- Pack Quantity (U‑Bolt Sets):4 U‑bolts (set of 4)
- Intended Application (Truck Chassis):Suspension mounting (truck)
- Additional Feature:E‑coated black finish
- Additional Feature:2.75 W × 6.75 L dimensions
- Additional Feature:Lifetime replacement warranty
16″ Square U-Bolt Kit with Tie Plates
Medium‑sized trucks that carry heavy headage racks need a bolt that won’t bend under load, and the 16‑inch square U‑bolt kit with tie plates delivers exactly that. You’ll get four alloy‑steel, square‑head U‑bolts, each 5.8 inches of thread, paired with four 6‑inch tie plates, eight flat washers, and eight lock nuts. The Grade 8.8 steel, black powder coating resists rust, stretch, and wear while providing high bearing capacity. Install them on a medium‑sized chassis to secure headache racks, cab racks, or suspension components. The kit offers strong, stable support without sacrificing durability or ease of installation.
- U‑Bolt Length:16 in (square)
- U‑Bolt Diameter / Thread Size:5/8‑10
- Tie Component (Plate/Bar):6 in tie plates
- Material / Finish:Alloy steel, black powder coating
- Pack Quantity (U‑Bolt Sets):4 U‑bolts (kit)
- Intended Application (Truck Chassis):Medium‑sized truck chassis / headache rack
- Additional Feature:Black powder coating
- Additional Feature:Grade 8.8 alloy steel
- Additional Feature:8 lock nuts included
Factors to Consider When Choosing a Headache Rack U Bolt Kit
When picking a head‑rack U‑bolt kit, you’ll want to check the material and bolt strength to guarantee it can handle your load. Make sure the thread size matches your rack and that the tie‑plate dimensions fit the mounting points. Finally, consider the finish’s durability and the U‑bolt head style for both protection and aesthetics.
Material Bolt Strength
Choosing the right bolt strength for a headache‑rack U‑bolt kit starts with understanding the grade, which tells you the tensile capacity and durability of the alloy. Grade 8 bolts, for example, use a high‑strength alloy steel that can bear considerably heavier loads than lower grades, so they’re ideal for demanding cargo. You should also match the bolt diameter to the expected stress; a thicker shank distributes force more evenly and reduces the chance of deformation. Look for corrosion‑resistant finishes—galvanized or coated steel—to keep the bolts from rusting, especially when you haul in wet or salty environments. By aligning grade, diameter, and protective coating with your truck’s load requirements, you’ll secure the rack safely and maintain its performance over the long haul.
Thread Size Compatibility
If the thread size of your U‑bolt kit doesn’t match the mounting holes in your truck’s chassis, the rack won’t sit securely and could become a safety hazard. First, measure the existing holes with a caliper or thread gauge; this tells you whether you need a 5/8‑11, 1/2‑13, or 3/8‑16 bolt. Verify the measurement against the kit’s specifications before you buy. Using the wrong size can loosen under load, causing the rack to shift or fail. If your truck has non‑standard holes, look for specialty kits that offer custom thread options. Always double‑check the thread pitch and diameter; a precise match guarantees a stable, reliable installation and keeps your cargo safe on the road.
Tie Plate Dimensions
Even if the thread size matches perfectly, the rack can still fail if the tie plates don’t distribute the clamping force correctly. You need to size the plates so the clamping area matches the load you’ll carry. A 6‑inch‑wide plate spreads force over a larger chassis surface, boosting stability and load‑bearing capacity compared to a narrower option. Thickness matters too—1/4‑inch plates are adequate for light duty, while 3/8‑inch plates add strength for heavier gear. Align the plate dimensions with your U‑bolt size and truck application to guarantee the avoidance of gaps or over‑tightening. Proper fit verifies the bolts seat flush, preventing uneven pressure that could warp the chassis. Choose dimensions that balance coverage, strength, and your specific storage needs.
Material Finish Durability
When you pick a headache‑rack U‑bolt kit, the material finish is the first line of defense against rust and wear, so a durable coating like hot‑dip galvanizing or black oxide can dramatically extend the kit’s life. Choose a finish that resists moisture, chemicals, and abrasion; hot‑dip galvanizing offers a thick zinc layer that shields the steel, while black oxide adds corrosion protection and a low‑profile appearance. Pair the coating with heavy‑duty steel—Grade 8 or alloy steel—to boost load‑bearing capacity and reduce bending under stress. Proper heat treatment further raises tensile strength and fatigue resistance, ensuring the bolts hold up to repeated loading. A high‑quality, long‑lasting finish therefore safeguards the hardware, keeping your truck rack reliable for years.
U‑Bolt Head Style
Choosing the right U‑bolt head style is pivotal because the shape of the bolt’s ends directly affects grip, load distribution, and stability on your rack. Square heads give you the strongest bite; they spread load evenly across the rail and resist slipping, making them ideal for heavy-duty truck and trailer rigs. Round heads are more adaptable and work in many scenarios, but they don’t lock in as tightly, so expect a bit more play under high stress. U‑shaped heads wrap around cylindrical items like pipes or tubes, letting you secure odd‑shaped cargo without extra hardware. Match the head to the material you’re clamping and the stability you need: square for maximum grip, round for versatility, and U‑shaped for wrap‑around applications.
Corrosion Resistance Rating
A solid corrosion resistance rating tells you how well the U‑bolt will hold up against rust, oxidation, and harsh environments over time. When you compare kits, look for material specifications: galvanized steel, especially hot‑dip galvanized, and Grade 8 stainless steel rank highest. These alloys form a protective layer that resists moisture, salt, and road grime, keeping the bolt’s tensile strength intact. In coastal or winter climates, a higher rating can mean years of service without replacement. Check the product sheet for the exact coating process and grade; manufacturers usually list “hot‑dip galvanized” or “stainless‑steel 316” to indicate superior durability. By matching the rating to your region’s exposure, you guarantee the rack stays secure and the bolts won’t weaken from corrosion.
Weight Capacity Rating
Even if you’ve secured a rust‑resistant U‑bolt, the kit still must handle the load you’ll place on the rack. The weight capacity rating tells you the maximum pounds or kilograms the U‑bolt kit can safely support, so you can’t overlook it when you load heavy tools, ladders, or storage boxes. Choose a rating that exceeds the combined weight of the headache rack, any accessories, and the cargo you intend to carry. A higher rating usually means a sturdier, more durable kit, but over‑specifying can add unnecessary cost and weight. By matching the rating to your actual load, you keep the rack stable, protect the vehicle’s frame, and avoid dangerous failures while driving.