BASH question: executing a cmd with a pipe that is in a variable

[Larry Cook]

I'm being stupid!  Can someone please help?

I've got a BASH script with the following:

     CMD="zcat myfile | tar xf -"
     $CMD

This puts zcat's output to stdout, rather than piping it to tar like I want. 
Now I'm sure this is how it *should* work. :-(  Unfortunately, I can't figure 
out how to get it to work like I want.

Thanks,
Larry