Model for differential tension and error correction efficiency at chromosomes of different sizes. Schematic of an assembling spindle depicting early alignment of short chromosomes and delayed congression of long chromosomes. Based on our findings, we propose that these delays are due to elevated polar ejection force and thus elevated kinetochore tension, which stabilizes both correct and incorrect attachments. Despite this stabilization, long polar chromosomes typically manage to biorient, suggesting an existing mechanism for detecting errors subject to modest kinetochore tension after some delay. Detection of these errors could occur via a graded tension threshold wherein low-tension attachments are corrected immediately, moderate-tension attachments after a delay, and high-tension attachments after a longer delay. Alternatively, the error correction machinery could rely on a tension-independent mechanism for error detection in these cases.