An interesting graph showing the average speed of the cyclists over the years in the Tour de France. One would expect to see a bigger jump over time with the technology that has been developed. So much money has been injected into developing the lightest and best bikes trying to give the cyclists the edge over their competitors. The development of carbon fiber and streamlined clothing hasn't really improved the times over the last 10 years and is kind of stagnated today.
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Steroids I don't think would have influenced anything as it is widely spread and must have been going on for years before the first rider was caught.I think there is something else that has actually slowed the race down and that is information.
In the mid 1990's radios were commonly used for team directors to stay in contact with their riders. The information fed to them would let them know who was up front in a breakaway and how far ahead they were. The chase could be more calculated and therefore the race would be slower than what it could have been.
We see very few breakaways succeed today and I think this technology should be taken away. If the riders have no idea how far ahead the break away is then it would change the entire race and I think would make for better viewing. For me cycling has become to clinical and calculated and I would love to see it have more raw talent.
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Biking is big business and any developments will trickle down to more affordable bikes over time. A Tour de France team bike will set you back around $15 000 with all the extras and specialised paint jobs.