changing bikes

One story about getting a new bike. I remember going slow on my old bike that I got on amazon many years ago. I was doing 12 mph and uff it was hard. Then I got a new spezialized rubaix carbon bike light as a feather and super fast. Suddenly I was doing 20 mph and even faster on my new bike. I increased my mileage alot too. No carpal tunnel issues. No back issues and all the issues from my old bike gone. 100 miles was like nothing. I started doing 100 milers every sunday. Then one day I had to return my rubaix for maintainance and had to use my old bike again. And was surprised that my average was 18 mph even near 20 mph.... Getting better bike increased my speed on the old one.