Originally Posted by
terrymorse
Wobbly flailing heels is almost always caused by a poorly fitted bicycle.
Judging from posted photos of [MENTION=106129]timtak[/MENTION] on their bike, it's a good bet that bike fit is the culprit.
Not necessarily even wobbly, flailing heels - he's probably splaying his knees, to avoid his abdomen in his "lowest is bestest" position, and driving his heels inward.