Another great shop is Bicycle Sport Shop, they have excellent rentals doesn't have the Lance factor but I race for BSS so I am partial to them. I know they have cruisers, tandems, mountain bikes (all types) and even high end road bikes. There is a cruiser rental on Barton Springs Road which is a cool and vibrant area of town.

Overall Austin is relatively bike friendly. Meaning we're used to bikes. Some of the infrastructure is still a work in progress though but they try. What type of riding are you looking to do?