Adverbs frequently end in-ly; however, many words and phrases not ending in-ly serve an adverbial function and an-ly ending is not a guarantee that a word is an adverb.
Lance Armstrong's strength and endurance sometimes seem too extraordinary to be believed. Armstrong, a six-time winner of the Tour de France bicycle race who next month will try for his seventh straight victory, can cover 32 miles, or 50 kilometers, in one hour of riding. In contrast, the average cyclist covers 16 miles; a top marathon runner can cover 21 miles on a bike. Armstrong can ride up the mountains in France generating about 500 watts of power for 20 minutes, something a typical 25-year-old could do for only 30 seconds.
If you can pace yourself without overdoing, and you don't ride like an old person on a tricycle, 10 miles on fairly flat ground anywhere between 10 and 20 mph would be reasonable, depending on your bike. My pace on my old 26 mountain bike was about 12mph. Now I'm between 16 - 18 mph.