uiscrollview initial offset

Question

For some odd reason a UIScrollView I use displays content with an initial offset (about 40) that I can't seem to get rid off...

CGRect newBounds = PieChart.bounds;
newBounds.size.height = newHeight;
PieChart.bounds = newBounds;
[scrollView setContentSize:newBounds.size];//has offset
// scrollView.contentOffset = CGPointMake(0.0, -40.0);