Work on the SU-101 and SU-102 at the Uralmash design bureau had basically started parallel to the creation of the SU-100, in summer 1944. While the latter, based on the chassis of the T-34 medium tank, proved satisfactorily in combat, its basic layout with crew compartment in the front and engine in the back was considered a flaw. The lowly mounted gun protruded far from the vehicle's front, which resulted in cumbersome maneuverability in urban or forested areas and could cause problems in undulating terrain, where the vehicle could potentially ram its own muzzle into the ground if not driven carefully. Additionally, the SU-100 was very front heavy, which resulted in excessive stress on the forward road wheels, risking mechanical failure. Should the need for upgrading the vehicle with a bigger and heavier gun arise, all these problems were expected to be massively exacerbated.