I'm 67 and 150 Pounds and seem to have the opposite problem, if it is a problem, in that I have never needed to pee on a ride, although my rides only average 2 to 3 hours. Even the occasional longer ride doesn't get interrupted.
I think it's due to the fact that I don't drink much on a ride, perhaps a quarter of a litre over 2 hours. I rarely feel thirsty and don't seem to sweat as much as my friends, even when working hard. I start out with the intention of drinking more but just never think of it, except on very hot days, which we don't get too many of in the UK.
Is the level of hydration required similar for all sizes of riders?