Originally Posted by T-Mar

I believe the odd stack height is due to the frame builder, Miyata, using one of their stock fork/steering tube lengths. The OP's bicycle is a 1981 model and at that time the Team Miyata (which is the equivalent frame) was being designed for Dura-Ace EX, while Lawee spec'd Campagnolo for their Super Speciale. There's not a bid difference in the stack heights but as of 1980 Dura-EX used the Dyna-Drive crankset which lowered the shoe to pedal interface by approximately 15mm. Miyata offered a 61cm Dyna-Drive frame as the closest frame size to Univega's 60cm. However, that still leaves a difference of about 5mm and I'm wondering if Miyata found it easier to install thicker headset spacers than manufacture and stock two different fork sizes for standard versus Dyna-Drive frames?