We have expanded on our previous work using bulky terminal groups to promote the SmA phase in cyanobiphenyl mesogens by using terminal cyclic groups separated from the core using relatively short aliphatic chains. The enhancement to smectic layer spacing observed in cyanobiphenyl materials with bulky terminal groups is a steric effect, and occurs without change in orientational order parameter. Provided a bulky group is present, the layer spacing is ~1.6 times the molecular length regardless of terminal ring size (5), alkyl chain length (8, 9 and 10) and linking group (9 and 11). This effect can be exploited to give significant increases to the onset transition temperature of both nematic and smectic mesophases, as demonstrated by comparing compound 9 to its linear analogue. Results from fully atomistic MD simulations support the overall interpretation from experiment that a cyclic end-group on the alkyl chain reduces the interpenetration of molecules between smectic layers in these systems. This phenomenon points to a potentially new method for stabilising both nematic and smectic liquid-crystalline states should the accompanying increase in melting points be countered.