Measure the outer diameter or width of the pipe, bar, or object you are clamping. Add twice the thread engagement depth you need, then select the leg length that matches. For example, a 50mm leg (≈2") is typically suited for smaller-diameter pipes, while 100mm+ legs (≈4"+) work for larger sections. When in doubt, size up — you can always add a washer to take up extra thread.

M8 stainless steel A2 U-bolts generally have a proof load in the range of 1,600–2,000 N per bolt when properly torqued. Actual working load depends on the application, clamping configuration, and safety factor applied. For structural or safety-critical applications, consult an engineer and verify with the specific grade datasheet.

Yes. Stainless steel A2 (equivalent to 304 stainless) offers good corrosion resistance in most outdoor environments. For highly aggressive marine or coastal environments with prolonged saltwater exposure, A4 (316) stainless is generally recommended. These bolts are well-suited for trailers, outdoor pipe runs, and light marine applications.

These U-bolts use standard metric M8 coarse thread (M8 × 1.25 pitch), which is the most common M8 thread pitch. They are compatible with standard M8 metric nuts and washers available at any hardware store.

The format is Thread Diameter × Inside Square Width × Leg Length, all in millimeters. So M8×25×50 means: M8 thread, 25mm (≈1") inside square width, and 50mm (≈2") leg length. Choose the inside width to match the pipe or bar outer dimension, and the leg length to provide enough thread engagement through your mounting plate.

Yes. Each set includes the square U-bolt body, a square bearing plate, and the corresponding M8 nuts. The quantity per set varies by the option you select — available in 2, 3, 4, 6, 8, 9, or 12 pieces per order.

M8 square U-bolts are commonly used on light trailers for securing axles, leaf springs, and pipe clamps. Verify that the inside square width matches your axle or spring pack width, and that the leg length provides adequate thread engagement. For heavy-duty trailer axles, larger bolt diameters (M10, M12) are typically used — M8 is generally suited for lighter-duty trailer applications.

A square U-bolt has a 90° bend forming a rectangular shape, making it ideal for clamping square or rectangular tubing, leaf springs, and flat surfaces. A round U-bolt has a curved bend suited for round pipes and tubes. Choose square when your application involves flat, square, or rectangular profiles that need full surface contact.