Prepare basic measurements
Record height and inseam, and describe any discomfort on previous bikes. Size labels vary across brands and generations; avoid transferring an old label directly to a new bike.
Check control and posture
In a suitable setting, try the bars, brakes, steering and mounting. Discuss your expected ride duration rather than relying on a brief seated impression.
Keep adjustment notes
Note the model, size and how adjustments feel. Do not use persistent pain as a test of adaptation. Adjustments must remain within the bicycle’s permitted limits.