{"product_id":"atnvidsg-roof-box-u-bolt-clamps-85mm-universal-stainless-steel-4-piece-mounting-kit","title":"ATNVIDSG Roof Box U-Bolt Clamps — 85mm Universal Stainless Steel 4‑Piece Mounting Kit","description":"\u003cp\u003e\u003cstrong\u003eATNVIDSG Roof Box U-Bolt Clamps are a 4-piece stainless-steel mounting kit designed to securely attach cargo boxes to most 85mm-width roof racks without drilling.\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cp\u003eThese U-bolt brackets and accessories give a simple, reusable way to fasten a cargo box to a vehicle’s crossbars. Built from stainless steel with rubber gaskets and plastic backing plates, the kit balances corrosion resistance and vehicle protection. It comes with all necessary hardware — U-bolts, washers, back plates, lock nuts, straps and a sealing sticker — so you can mount or remove a roof box quickly while keeping scratches and movement to a minimum.\u003c\/p\u003e\n\n\u003ch3\u003eHow do these clamps fit different roof rack sizes?\u003c\/h3\u003e\n\u003cp\u003eThe clamps are made for crossbars with an inner gap of about 85 mm and an outer width near 90 mm, and they accept bar thicknesses up to roughly 40 mm. Check your rack’s inner width and thickness before ordering to ensure compatibility.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eInner width: 85 mm (3.35 in)\u003c\/li\u003e\n  \u003cli\u003eOuter width: 90 mm (3.54 in)\u003c\/li\u003e\n  \u003cli\u003eAccepts bar thickness: up to ~40 mm (1.57 in)\u003c\/li\u003e\n  \u003cli\u003eIncludes two adjustable straps for added hold\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhat materials and protections are included?\u003c\/h3\u003e\n\u003cp\u003eThe kit uses stainless steel for the U-bolts and durable plastic for backing plates, paired with rubber gaskets to protect paint and increase grip. These materials resist rust and deformation, helping the hardware last through seasonal use.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eStainless-steel U-bolts resist corrosion\u003c\/li\u003e\n  \u003cli\u003eRubber gaskets cushion and prevent scratching\u003c\/li\u003e\n  \u003cli\u003ePlastic back plates distribute clamping pressure\u003c\/li\u003e\n  \u003cli\u003eSealing sticker helps protect the roof hole area\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eHow hard is installation and what comes in the box?\u003c\/h3\u003e\n\u003cp\u003eNo drilling is required: the parts are designed to clamp around existing crossbars and secure with supplied lock nuts. The set includes everything needed to mount a typical cargo box, and instructions are straightforward for a DIY install.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e4 stainless-steel U-bolts\u003c\/li\u003e\n  \u003cli\u003e4 rubber washers and 4 plastic back plates\u003c\/li\u003e\n  \u003cli\u003e8 lock nuts and 2 long straps\u003c\/li\u003e\n  \u003cli\u003e1 hole sealing sticker and simple fitting steps\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWill these clamps keep my cargo box stable on rough roads?\u003c\/h3\u003e\n\u003cp\u003eThe combination of secure U-bolts, anti-slip rubber, and supportive back plates reduces shifting and helps maintain a stable load through bumps and turns. Straps add redundancy to prevent loosening while driving.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eRubber increases friction to limit sliding\u003c\/li\u003e\n  \u003cli\u003eBack plates spread load to prevent concentrated pressure\u003c\/li\u003e\n  \u003cli\u003eLock nuts secure hardware against vibration\u003c\/li\u003e\n  \u003cli\u003eStraps provide secondary restraint for safety\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eWho is this for: The ATNVIDSG Roof Box U-Bolt Clamps suit drivers who need a universal, non-permanent mounting solution for rooftop cargo boxes—especially owners of crossbar systems around 85 mm inner width who want corrosion-resistant hardware, protective gaskets, and complete installation parts in one compact kit. Before purchasing, measure your crossbar inner width and thickness to confirm fit. If you need additional help choosing the right size or have fitment questions, reach out to the seller for guidance.\u003c\/p\u003e\n\u003csection class=\"product-faq-snippet\"\u003e\u003ch3\u003eFAQ\u003c\/h3\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003cp class=\"faq-q\"\u003eQ: Will these clamps fit my crossbars?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: They fit crossbars with an inner width of about 85 mm and thickness up to ~40 mm; measure your bars before buying.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003cp class=\"faq-q\"\u003eQ: Do I need to drill into my roof to install them?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: No drilling required — the clamps fasten around existing crossbars and use supplied hardware and straps.\u003c\/p\u003e\n\u003c\/div\u003e\u003c\/section\u003e","brand":"ATNVIDSG","offers":[{"title":"Default Title","offer_id":48086856663198,"sku":"B0BRJGLX33","price":30.47,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0781\/2041\/9486\/files\/atnvidsg-roof-clamps-front.jpg?v=1785908184","url":"https:\/\/northtrailauto.ca\/products\/atnvidsg-roof-box-u-bolt-clamps-85mm-universal-stainless-steel-4-piece-mounting-kit","provider":"North Trail Auto","version":"1.0","type":"link"}