M8 U-Bolts Round Bend A2 Stainless Steel — 22mm to 161mm, Choose Your Pack

Measure the outer diameter (OD) of the pipe or tube you are clamping. The shank length should be at least equal to the pipe OD plus the combined thickness of your mounting plate, plus roughly 16–20mm of thread for two nuts. Example: a 25mm OD pipe on a 4mm plate generally needs a shank of 45–51mm. When between sizes, choose the longer option and use flat washers to take up extra thread.

A2 (Grade 304) stainless steel is highly resistant to rust in most outdoor conditions — rain, humidity, UV, and light coastal spray. Surface discoloration (tea staining) can occur in high-chloride coastal zones but does not affect structural integrity. For continuous saltwater immersion or aggressive marine environments, A4 (Grade 316) stainless is generally the better choice.

These U-bolts use M8 metric coarse thread with a 1.25mm pitch — the standard pitch for M8 fasteners. They are compatible with any M8×1.25 metric nut, nylon insert lock nut, or flange nut. They are not compatible with imperial (SAE/UNC/UNF) hardware.

The 12 available shank lengths (22mm to 161mm) cover a wide range of pipe and tube outer diameters. As a general guide: 22–27mm shanks suit small conduit and tubing up to ~20mm OD; 42–60mm shanks suit 1"–1.5" nominal pipe; 76–114mm shanks suit 2"–3" pipe. Contact us with your pipe OD for a specific recommendation.

A2 stainless steel is generally suitable for moderate-temperature applications. For exhaust systems that reach sustained high temperatures (above approximately 400°C / 750°F), a high-temperature alloy or A4 stainless with appropriate heat shielding is typically recommended. For standard automotive exhaust clamps at normal operating temperatures, these U-bolts are generally adequate — confirm your specific temperature range before ordering.

Please check the variant options on this listing or contact us to confirm hardware inclusions. In most cases, round bend U-bolt sets include two M8 nuts per bolt. Washers are not always included — confirm before ordering if your installation requires a complete hardware set.

Round bend U-bolts conform closely to the curved surface of round pipe or tube, distributing clamping load evenly and reducing the risk of surface damage or stress concentration at contact points. Square bend U-bolts are typically used for rectangular or flat stock. For standard round pipe, conduit, and tubing, a round bend profile is generally the correct and preferred choice.