Originally Posted by
asgelle
Cervelo use horizontal dropouts so the spacing between the wheel and seat tube can be made as small as possible (or legal) for different size tires. They're not necessary to get the wheels in and out on the P2 or P3 series.
THIS. Ironman referees are hardasses. Sometimes they will go around the transition with a "gauge" (credit card or such

) and check the spacing between the frame cutout and the tire.
Don't get me started on their drafting calls, man.