I love this forum already! I have this exact same bike
Thanks mate, nice to connect!
I have been riding on GP4000 25mm for 2 years, and recently changed to an old pair of Vittoria (25mm/ gum walls). Didn't think I would say this but riding on the older pair feels softer and nicer on the road, or so it feels.
How long have you had your SystemSix for? What was your riding experience changing from 25 to 28mm?