What's the difference between an upright bike and a folding/recumbent bike?

Upright bikes mimic a traditional bicycle posture and tend to have a smaller footprint. Folding bikes (several 5-in-1 models here) collapse for storage and often convert between upright and semi-recumbent positions, which buyers with small apartments favor. Recumbent bikes, like the Sunny Health model, put you in a reclined, back-supported seat that reviewers frequently recommend for seniors or anyone with lower-back concerns.