According to the search results, the size of trucks for an 8.5 deck can vary depending on the brand of trucks. However, most sources suggest that trucks with a width of 8.5 inches are suitable for decks between 8.5 and 8.75 inches wide. Some specific truck models that are recommended for an 8.5 deck include Independent Stage 4 151 trucks and Independent Stage 4 166 trucks. It is important to match the width of the trucks as closely as possible to the width of the deck for optimal stability and turning performance.