One thing to check too, can your rear derailleur take up the extra chain associated with a 32t cog. Also, you will probably need to lengthen your chain to use it. What kind of grades are you talking about here? I agree with others that it is better to upgrade the engine rather than the gearing if possible, but I also agree that sometimes you need to do both. I have lowered the gearing on my bike significantly since I purchased it a few years ago, down to a 34-26 from a 39-23, but I still have to stand and grind up certain hills in my area because they are still too steep to spin up. Others though are easier to ride, which makes a big difference in a long ride. So the long answer to a short question is that it really depends on what you are riding and how long you have been riding. If you have been riding for a while and still can't make it up, lower gearing may be the answer. If you are just starting, it depends on how steep the hills are that you are riding.