In 165/70, 165mm is the width, 70% of 165mm=115.5mm is the profile (height)
In 145/70, 145mm is the width, 70% of 145mm=101.5mm is the profile (height)
In 145/80, 145mm is the width, 80% of 145mm=116mm is the profile (height)
So 165/70 is closest(-0.5mm) in terms of profile to the stock.