Originally Posted by Helderberg

I will admit up front that I have no frame of reference to a carbon frame but this was my experience. I ride a aluminum 2020 105 Topstone. I stopped in a a LBS and rode, what I believed to be, my identical bike though it was a 2019 with Sram Apex mech. On my test ride I went out of my way to find as many seams, broken road, etc as I could and when I returned to the store I asked what the difference was in the frame make-up that made the bike feel so different from mine? She told me there was nothing different in the frame. The tires were the same brand but different model and mine are 37c and the Apex was 40c. Also the 2019 I just rode were inflated 25 lbs less than the pressure I ride. Again, I realize this is not the comparison you are looking for nor is it close to the equivalent to what has been said here but I just thought the observation of the difference in tire pressure and tire width/model was so drastic that it might be of some interest. I saw a carbon Topstone a few days later and my credit card went into hiding as that was an incredible piece of workmanship and if I had seen that when I was buying my Topstone this comment would be a lot different.
Frank.