LSI (Load Symmetry Index) can be different on trimmed shafts. It doesn’t really matter since no shaft is perfectly straight or perfectly round. An LSI of 100 means that the shaft is perfectly straight and round. Never seen one untrimmed or trimmed. The variance should be minimal from trimmed to untrimmed. The Pure process will identify the principle plane of oscillation, or the position at which the shaft will load and unload as if it where perfectly straight and round, and mark it for installation. It takes the inconsistency of how a shaft can load and unload when installed randomly out of the equation.
Pureing on steel shafts is just as important as graphite. I would say a lot of the steel shafts are not as straight as graphite, so they can benefit even more.
Britt Lindsey