Dry rubs for ribs can add an amazing layer of flavor to your beef or pork ribs. They don't really need to be all that complicated to make, but when you use them properly, they can turn a basic rib into something from heaven (or hell - depending on how much heat you put into the rub!).
You can of course buy dry rubs for ribs if you want to. Most supermarkets will sell you some sort of basic dry rub. If you're lucky enough to have a shop where you live that sells hot sauces and B.B.Q. sauces, you'll likely be able to get better quality rib rubs there. However, they are easy enough to make on your own that there really is not reason not to make your own dry rubs.
There are really only 3 questions you need to ask yourself when you are making your rubs:
1. do you want it sweet
2. do you want a spicy rub
3. what kind of flavor do you want the dry rub to give the ribs
If you want your rub to add some sweetness to the ribs, be sure to use sugar of some kind. Brown sugar, cane sugar can be very good as they also add nice flavors. You may want to dry them out a little (overnight on a cookie sheet) before using them in the rub to remove any extra moisture.
If you want a spicy hot rub, add in your favorite chili's or cayenne pepper.