For discussion of the Suzuki DRZ400 and Kawasaki KLX400. Note that the S pressure is for a 20 year old dual sport tire not a knobby, and that matters. Tires have changed a lot in that time. BEST always is to ask the TIRE manufacturer for their recommendations for your bike. Note that stock E pressure is 18 and 23 for road and 15 and 15 for.. The recommended tire pressure for your Suzuki DR-Z400S (2020) can vary depending on various factors. However, a general guideline is to maintain the front tire pressure between 22-24 psi and the rear tire pressure between 25-28 psi. Refer to the manual for specific recommendations based on your riding conditions.
Too low a pressure results in a "squirrelly" tire (sidewall flex etc) and also drastically increases your chances of pitched flats and tire slippage - the ability to turn the rim relative to the tyre (under acceleration or braking), which leads to valve stem damage and/or shearing - see fitting rim locks to prevent this. Too much pressure will.. Been riding a DRZ-S since 2004. Ridden the western TAT with it, both with tail pack and with small saddlebags. Dunlop 606 rear and either Pirelli M-21 or Kenda enduro tire up front. I keep my tires at 18 lbs. for the entire route, including the rocks and sand of Utah and the high speed dirt roads in Nevada.