The last time I was in Myanmar doing a logistics audit I searched through the Yellow Pages and scanned this full List of Tire Distributors and Wholesalers in Myanmar. You can also find the information in the section of Myanmar Yellow Pages online, but this PDF is easier to look through.
Myanmar Car Accessories Classifieds
Full List of Tire Distributors and Wholesalers in Myanmar PDF
Myanmar Yellow Pages Tire Distributors and Wholesalers Listing