Joined: Jul 2002
Posts: 40,863
Likes: 3,115
From: Sacramento, California, USA
Bikes: Specialized Tarmac, Canyon Exceed, Specialized Transition, Ellsworth Roots, Ridley Excalibur
You should have no problems with 28mm tires. I do it all the time on 23mm tires. It's not a big deal if the surface is dry. (If it's wet or icy though it can be extremely slick and dangerous. )