Any tire shop should have metal stems. I replaced mine on the road in Canada when the Chinese ones started to fly off at 65 mph. 2 went in less than a week.
WBCCI 12156 AIR 3144 WACHUNG TAC NJ6
2004 Excursion 4x4
1991 34 ft. Excella +220,000 miles, new laminated flooring, new upholstery, new 3200 lbs axles