Call Treddit directly and tell them your situation. There have been posts in the past that indicated they were willing to work out a deal, where they sold the individual three new wheels at a discount, and replaced the broken one under their warranty. So, you will end up with four new wheels, and have the other three to sell. This would be a better option than not having one, as these wheels are not made or stocked anymore. Their number in Elkhart-
855-887-3348