For 2011 & up GM 2500/3500 trucks that have a factory optioned upper overload leaf spring (a set of one or two leafs that reside about 1" above the main leaf spring pack). There just isn't enough usable thread length on the factory u-bolts. Not every truck has this option, so to minimize kit cost we decided to offer the u-bolts separately. Our u-bolts are made using USA sourced Grade 8 rod to ensure metallurgical integrity. The u-bolts, heavy hex nuts and heavy washers are then zinc plated to guard against corrosion.
Nominal specs: 3.1" wide (for 3" wide leaf springs), 12.5" length, 5/8" diameter rod.