Yes, go with the smaller cog. The weight difference between a 15T and a 14T is actually phenomenal. This decrease in rotating mass will allow you to increase your top speed by AT LEAST 8mph on level ground. Your acceleration will get better, and you will be able to get up hills like a pro. If you were to increase your chainring size by two (!) teeth, oh man, why would you bother adding that much weight? You might as well have someone riding on your handlebars!


In all seriousness, if you can find cheap chainrings in your BCD, I would swap chainrings. I haven't even done that much swapping, but just in theory I agree with a lot of the above, especially considering the difficulty and wear of swapping a cog vs. a chainring. You have to get that lockring off, and then the cog, which is probably quite sunk in there by now. You either need to use a chainwhip and all that jazz or get creative with the wheel mounted on the bike, versus spending a couple minutes with an allen wrench and a screwdriver.