I ride a flex-loop. I can vary it from 8 miles to 22, without backtracking too much.

Sometimes I ride with a group but they LIE. They'll say, oh, we're tired, let's only go 20 miles and inevitably they tack 10 more on.

If I really needed to force myself to ride further, I'd have my husband take me off and put me out on the side of the road 30 miles from home so I have to ride back.

Come to think of it, that's how I did my first "big hill conquering" ride.

He set me out on the side of the road and I had to ride it (the big hill) in order to get home. It's like giving a horse his head on the way back to the barn.