If the reference is for Twigg, then technically Schwinn didn't win a World Championship, as Twigg rode a Raleigh in the 1987 World Championships. However, since the World Championships typically are held around the beginning of September, the 12 month title reign spans two calendar years, while rider contracts are typically calendar year based. Consequently, it is fairly common practice for sponsors to elevate their prestige by contracting a reigning world champion whose sponsorship is set to expire. In such cases, the World Champion title is purchased by the sponsor, rather than won.