I just ordered my first road bike and I have a question regarding pedals. The LBS I ordered my bike from recomended that I buy another set of shimano spd's, like the ones I have on my mtb, to use on my road bike. I bought a set of shimano 540's and I threw them on my mtb and I am gonna throw my 520's on my road bike. This way I can use the same shoes for both bikes. I wear specialized comp carbon mtb shoes. Do alot of people who ride both mtb, and road bikes do this? Are there any disadvantages to doing this? Any info that you guys can give me will be appreciated. Thanks in advance for any replies that I get here.