User blog comment:Mystic Monkey/I've given too much thought into this/@comment-167456-20130913180541/@comment-679780-20130914005224

I've also notice they mostly given Sonic rings for cutie mark.

Why rings? Everyone in Sonic games can collect rings and doesn't truly represent Sonic's special talent. That's why I chosen his own shoe because ponies don't wear shoes (other than horseshoes) and his own shoe is used as a power-up icon for speed-up so it makes much more sense.