Here's my experience from when I started cycling four years ago. The distances I cycle have changed a lot and my speeds are held back somewhat by a permanent ankle injury and being 52! However, using what is now my shortest circuit of 17 miles as a benchmark.
1st year Subway 1 - goodbye to 4 stone and worked up to an average speed of around 14 mph by the the end of the year.
2nd year Dawes Discovery - instant increase to 15 to 16 mph average speed.
3rd year Ridley Aeron with tiagra - not much increase in speed but much more pleasant to ride, especially for 50 milers.
4th year Early training for first 100 miler and more use of drops, which increased average to 17mph but still very hard to go much faster.
4th year (part 2) bought lovely Orbea road bike - first trip out, averaged 19 mph.
The Orbea is a completely different riding experience. I seemed to hit a wall with the Ridley where extra effort made little difference but so far, that hasn't happened with the new bike. I doubt if I'll push myself much faster overall but it is nice to be able to give it some welly for a few miles and get some real exhilaration from the speed.
John
1st year Subway 1 - goodbye to 4 stone and worked up to an average speed of around 14 mph by the the end of the year.
2nd year Dawes Discovery - instant increase to 15 to 16 mph average speed.
3rd year Ridley Aeron with tiagra - not much increase in speed but much more pleasant to ride, especially for 50 milers.
4th year Early training for first 100 miler and more use of drops, which increased average to 17mph but still very hard to go much faster.
4th year (part 2) bought lovely Orbea road bike - first trip out, averaged 19 mph.
The Orbea is a completely different riding experience. I seemed to hit a wall with the Ridley where extra effort made little difference but so far, that hasn't happened with the new bike. I doubt if I'll push myself much faster overall but it is nice to be able to give it some welly for a few miles and get some real exhilaration from the speed.
John