Last week end I had to replace my rear tire, a Schwalbe Durano 700x23 that (only) lasted 3500 kms (2175 mi.) I decided to try bigger tires. The biggest tires I could fit on the bike are 700x28.

It's been a week or 220 kms (137 mi.) so far and I really feel slower, I feel like I need to put more effort to keep the same pace and my average commuting time is definitely slower this week. Is it me? Is it the tires? I've read a few thread on this forum stating that a bigger tire shouldn't make you slower but I don't agree so far.

It may just be the tires, they're Schwalbe Delta Cruiser 700x28, anyone familiar with those?
Bigger is definitely more comfortable but I choose speed over comfort.

Anyone having the same impression?