I use the 16,000lb Rhino Ramps as well. They're great, (Haven't used them on my Denali as of yet because I just got the car). I would reccomend changing them out every few years or so, they do degrade over time, always inspect them. My neighbor had his Rhino Ramps break apart last summer as he was loading his car on top. Inspect everytime you use them, for extra piece of mind have another item underneath to support your vehicle just in case and change them out every few years. The composite degrades over time (how long I don't know so I'll change mine every 3 - 4 years), and metal fatigues over time too.