Weight and speed

Since 2001, over 90,000 cyclist's have joined Cycling Forums to discuss topics from general cycling to equipment, training, racing and travel or vacation destinations (especially in europe during the tour de france). We also feature an great deals in our online store, 100's of articles, classifieds and product reviews.

I´m from Sweden, and was a pretty good runner in my youth. Now I´m 49 and has gained a lot in weight the last 15 years. Two years ago I started train on a race bike (Trek) and now I have a question regarding my weight (100 kilos, 220 pounds):
If I am able to train (solo) for 100K (60 miles) with an average speed of 28 km/h (17,4 mph) --- how fast would I go if my weight was 80 kilo (176 pounds)?
Best regards / Michael, slimmer for every day...

Weight makes the largest difference when climbing (due to gravity) and on the flat the frontal surface area is most important (due to aerodynamics).

Losing weight will have a number of physiological advantages too, for example improved blood pressure and circulation. These change will improve performance and health.