I do not know how old you are, what you weigh, your riding intensity, eating habits, etc. I do know that 2-3 mph increase for a ride of a lot of miles is no easy task. In 2017 I put 6,000 miles on bikes. I was doing intervals and fast paced longer rides, eating well, and I purchased a used titanium bicycle in June. My average mph went up 1 mph through June and another 2 mph from beginning of July to the end of the year. The last half of the year I was 15 pounds lighter and the titanium bike is about 4.5 lbs lighter than what I was riding before. At the start of the year I was 162 lbs. and by June I was at 147. The bike I rode the first half was about 22 lbs and the titanium bike was 17.5. I and my early bike weighed 184 pound to start the year and end of June the weight was at 164.5 Rounded off that means myself and my bike were 20 lbs lighter at the start of July. I held that weight through the rest of 2017. That is an 11% weight difference. My avg. mph went from 14.5 to 17.5 an increase of 3 mph. That equals an increase of 21% in the mph. What does all of that mean? It took an investment in time, work, discipline and money to get there. I am 66 years old and, trust me, it was not easy. But it sure was worth it!