With the second and third leg of the triple crown coming up I want to
know how many combinations ( and what those combinationa are ) i need
to bet to cover all the possibilities in a trifecta??

Here's a link on exotic wagering.  It covers boxing, wheeling,
trifecta key wheel, and trifecta part-wheel combinations.
http://www.handicapping.com/charts/buildtri.htm

The Preakness field is limited to only 14 starters, but it hasn't had
that many since 1992. There is no way at thois point to know how many
gates will open but you can figure 14 if you want to calculate the
maximum potential starters.

The Belmont contenders won't be posted until May 17th.

Regards;
tutuzdad-ga

all possible combinations of a trifecta can be determined by
multiplying the number of horses in a race by the next 2 lower
numbers.  For example in a 7 horse race the combinations would be 7
times 6 times 5 which equals 210 combinations. In a 5 horse race there
would be 5 times 4 times 3 which equals 60 combinations.  Regarding
what those combinations are : this could be done manually by setting
up a grid of columns or an easier way would be to use a web site such
as the one mentioned in the earlier comment from voila-ga.  P.S. If
you try to bet all combinations then you quickly find out that your
winnings dont cover your cost.  A better system is to wheel the
favorite horse