U-bolts are among the trailer parts that break most frequently, so even if you don't have any that are broken now, it might be a good idea to keep some of these Uriah Products U-bolts and nuts around the shop just in case. This model has a 7/16" diameter and can accommodate a 2" axle width. Be sure to check your existing U-bolts for wear so that, if need be, you can replace them before they break when you're on the road. | Uriah Square U-Bolt and Nut | Size 4" x 2"