I'm confused. Which stack is less aggressive? 544 mm or 528 mm? How I understand it is that the lower the number the more aggressive it is when it comes to stack. Because it's like the elevation of your entire arms and hands when you're on the bike. Am I wrong? I'm planning to get a new bike. My choices are the Giant TCR and Specialized Tarmac. I want to pick the bike with less aggressive geometry. TCR has a 528 mm stack and the Tarmac has a 544 mm stack. Reach are almost identical with 1 mm difference. Thank you for your replies.