Woman spinning on the great or walking wheel.
Luttrell Psalter, British Library, London 14th c. England
The great wheel produced thread more quickly than the drop spindle, but the thread was lower quality. It was underspun (not twisted enough) and uneven. The wheel was turned by pushing a stick against the spokes (above) or by turning a crank. Because the spinner had to use one hand to operate the wheel, she was left with only one hand to draft the fibers, resulting in uneven thread.
Woman spinning on a great wheel which is turned by a crank. MS 17, Musee Dobree, Nantes 16th c. France
The spinners above are drafting the fibers with one hand and turning the crank with the other. The next step in the evolution of the spinning wheel was to attach a foot treadle to the crank. The spinner could then use her foot to turn the wheel, freeing both hands for drafting.