Originally Posted by
vega2614
Now it shifts pretty well, but apparently the front 105 works for a double or triple crank so you have to be careful about shifting with a double, as to not shift to a non-existent gear.
The middle position will allow you to run more gear combinations without rubbing the derailleur as bad. For example, when cross chaining small front / small rear or big front / big rear. With this said keep in mind that cross chaining is never the best thing to do but it does happen from time to time.