For any type of off road driving in the UAE you need to reduce your 4x4 tire pressure. For mountains and wadi it's easy to reduce between 20-25 PSI irrespective of the tire brand, shape, type and load. For sand the tire pressure deflation is little bit tricky and if you follow below steps, you can decode this better. Before that you also need to understand that why deflation for off road driving is so important: Deflated tires are hard to sink in or dig in the sand due to lesse