When PGA professionals cut their driver down (ie Fowler) to 43 1/2 inches for consistency, does the shaft need to also be tip trimmed to maintain is flex? What happens if you only butt trim and not tip trim?
Butt trimming does very little to affect shaft flex. Typically, shortening the shaft will lighten the swingweight, so if weight is added to the head to make the swingweight the same as before, the shaft will play slightly more flexible. Most players can’t tell the difference, IMO.