High quality metal valve stems are the only way to go, I have them on all 5 of my trailers...one less thing to worry about at 65mph with 10,000 pounds of machinery in tow.
Another trailer/tire factor I see wrong a lot is tow angle, with a dual Axel trailer , all four tires should sit level at all times, I see alot of 4x4 trucks pulling trailers at odd angles, stressing the rearmost tires to their limit, the proper drop sleeve should always be used and I recommend a solid one, backed up with 4 breakaway chains, not 2. I can't believe there are not more accidents with the crazy rigs I see some fools pulling.
Another trailer/tire factor I see wrong a lot is tow angle, with a dual Axel trailer , all four tires should sit level at all times, I see alot of 4x4 trucks pulling trailers at odd angles, stressing the rearmost tires to their limit, the proper drop sleeve should always be used and I recommend a solid one, backed up with 4 breakaway chains, not 2. I can't believe there are not more accidents with the crazy rigs I see some fools pulling.