I know many of you perform RDL's with a bar using the standard clean grip which is shoulder width. That's how you were probably shown and it works. But... I have a small change and it doesn't require you to stand on something and use anything other than the bar you're accustomed to.
Instead of using a clean grip when you perform RDL's, try using a snatch grip (very wide grip). This will not only increase the ROM the bar travels it will also bring the lats and upper back into play.
Here's a vid illustrating the variation of the movement. Give them a try, I think you'll be pleasantly surprised...