TIM barrel proteins are one of the most common motifs in biology, providing a myriad of catalytic platforms for enzymes found in all three super-kingdoms.Although the topology is highly conserved, the wide variation in sequences provides a robust system to dissect the relative contributions of topology and sequence to folding mechanisms.Using a combination of mixing and spectroscopic techniques spanning the micro-to-kilosecond time range, we find that the topology determines the fundamental features of the folding free energy surface.