Yes, though for a good chunk before 1413 the system was in its birthing period and was yet to be fully developed.

The timar had two purposes: one, it was a reward for good service, two, it was meant to raise an army. Every timar holder was obligated to arm himself and a number of cavalrymen(number depending on value of the timar), with peacekeeping duties in peacetime, and had to report to the army in wartime.

The recruitment of the Timariot Sipahi units were inherently tied to the timar system. Without it you wouldn't have sipahis. The equivalent would be their predecessors the Müsellem semi-irregular cavalry corps.