If have already visited Nandi Hills and Skandagiri Hills, I would suggest you to visit Horsley Hills at the border of Andhra Pradesh. It's a 3-4 hrs of ride, and if you are able to reach there by - say 5:30 in the morning, you might fall in love with this place.
You can also try Yellagiri hills if you just need a bike ride. Other than that there is nothing much to see up hill.
Hope this help. Happy Travelling...😊