Originally Posted by jorantes
I know there are the different grades of components shimano produces (sora, tiagra, 105, ultegra, da) but what are the actual differences/advantages that makes one better than the other, guy at LBS who has been riding for many many yrs couldnt really give me an answer on that... thanks!
A complete 105 group is all anyone really needs, it's just that they want Dura-Ace.
105 is good enough for about 95% percent of riders. For some of them it's more than they need.