Question about Roth IM

I found posts dating back to 2006 and most answered one question…that it is a fantastic experience and one heck of and ironman.
My main question out of curiosity mostly is why are the pros able to post such fast times breaking 8 hours at times?
thanks
Would like to do Roth after I get out of chiro school

I heard the course is “short”.

I did the race in 2001 and my bike computer had the ride as pretty much bang on 180k. The bike is actually reasonably challenging with some good climbs throughout the loop. The pavement is awesome so that helps a lot, as does the thousands of spectators cheering you on. The competition there is very strong which also brings out the best in the pros.

The swim is in a canal so fast swims are the norm (it is very easy to swim straight and you aren’t getting any choppy conditions).

The run is very flat and the trails are forgiving on the legs. There are also hoards of people cheering you on throughout the run.

Anyone who has done IMC or IMLP and thinks that the spectator support is encouraging there (it is!) will be wowed if they travel to Roth where the spectator support puts even these great North American races to shame.

The weather conditions at Roth are not usually as extreme as some of the other races where great fields are assembled (although in 2001 it poured rain on me for about 170k of riding!)