It is OK to use springs with different spring lifts but it is better to have matched springs (wire size, coil length, coil diameter, etc.). If you use mismatched springs try to keep them nearly alike, it is acceptable, to to lift a 190 lbs garage door with two springs, one 100 lbs. and the other 90 lbs lifts.
Using different spring to balance a garage door helps to minimum inventory, but the combined IPPT’s (inch pounds per turn) or spring lift must be correct for the door.
We highly recommend using springs that are matched for the following reasons:
• Unmatched springs have different cycle life, but usually both springs are replaced at the same time, the remaining cycles of the unbroken spring will go unused.
• If the different is large between springs, it may pull the torsion bar to one side, causing cable drums to scrape, cables to peel off drums, and flag bracket to come loose.