The closest spring we have to what you need for your daughters 2005 Forest River Flagstaff Popup Camper is the 3-Leaf Double-Eye Spring for 3,500-lb Trailer Axles - 23-1/8" Long # e59SR which measures 23-1/8" center of spring eye to center of spring eye which is likely what her trailer needs due to springs getting longer slightly as they wear out.
The # e59SR is rated for 3500lb axles, or 1750lbs per spring which will still work for her trailer, and though it has 3 leaf's the rating of... view full answer...