The diameter of the actual bolt used. Put a caliper on the threads to get this measurement. Our UBolts are Fine Thread (SAE).
When ordering your UBolt, the diameter you order will be the diameter of the threads. The un-threaded portion of the UBolt is approx 1/64 to 3/64 smaller in diameter.
Inside Width (we bend around a die this size). Some ubolts will measure slightly wider due to the rod material. When you properly torque the ubolt, normally they will tighten in to the width chosen. U-Bolts must be tightened and torqued properly using a cross pattern sequence. View the torque guide here
Inside Length of the UBolt. The thread Length on U-Bolts are generally 1 1/2"- 3", or more depending on the length of the rod.