In reply to BattyMilk:
Just been for a look, my tyres are 25mm Conti GP 4 season, granted they're not fully pumped up and my Allez is a 2014 frame but....
The tightest clearance from the sidewall is on the drive side chainstay and it's 4-5mm, other side chainstay is 5-6. Seatstays have another 2mm each side, I reckon there's about 4-5mm from tread to rear brake mounting bar.
On the front there's at least 6mm from sidewalls to forks and above tread.
Mark