Tires make a huge difference. If you are running average tires, upgrading to something like 32 or 35mm Vittoria Randonneur Voyagers might add 1-2mph to your average. If you are riding particularly "slow" tires, the Vittorias might add even more.

I will note that by "good" I'm referring to how the tires are constructed and what they are constructed from, rather than width.


Good tires are not cheap but they are a worthwhile investment.....probably the best investment a person can make for their bike. The first time I upgraded it took a long time to commit to doing it and it was painful but once I saw how much difference good tires makes, I was convinced. If I had a specific ride planned and my research told me that a $150 set of tires were the best for that ride, I wouldn't hesitate to buy them.