Start Gore without a doubt!! He is a No 1 RB this week.
-The Colts haven't favored well against the run
-The 49ers have a changing of the guard at QB and will likely stick to the ground as they feel out Smith's arm/ability
-Gore should finally be 100% and will look to make up for a subpar week 7
Bell is a nice flex start ... but still risky; I don't know if you can trust that he'll be the consistent goal-line back after observing only one game with he and PT sharing the field. That being said, if I were you - I'd consider starting both!
Take a look at my post?http://www.fantasyfootballcafe.com/forums/viewtopic.php?f=19&t=458323