I had some 35/12. 50/17 Toyo Open Country M/T put on today and when I got home I noticed that didn't reinstall the metal (high pressure?????) valve stems that were on it before. Is this a big deal? What kind of pressure will these take? I checked the air in them and they have 38 lbs. in each tire. What will these valve stems do if I max out tire pressure at 65lbs. while towing? Or any thoughts on IF I should max them (REARS) out while towing my 5er???? thanks...