One of the replies here said it would not make any difference if u added ankle weights, what you are really doing is adding weight to the bike. After reading that, I took off the weights and put them on my carrier thus increasing the weight of the bike.. I am now pedeling a 48 pound bike and I have the same effect as when I had the ankle weights. I am riding the same route faster now with the heavier bike. When I do my next centruy I will take the weights off the bike (If I can remember ha ha)..at my age I forget things sometimes...