Going from 44" to 43.5" decreases swing weight by 3 points and while increasing swing shaft weight generally increases swing weight by 1 point it can vary when going to a new/different shaft due to a difference in balance point- difference in balance point can have a significant effect on swing weight.

No surprise that you lost distance. By shortening the shaft, you will loose distance. Most current drivers are 45". The 913D2 was a great driver in it's time. It came out in late 2002. They have made lots of improvement over the past upgrades; 915D2, 917D2, TS, TSi2. That is moving forward eight years in R&D.

The new TSi line appears to have moved the drivers to another level, which you might want to look at. I play the 917D2 11.25 has shown much improvement over the 913 and 915 but I did not get much improvement with the TS.....I will be getting a fitting for the new TSi2 based on my research.......at 75 yrs the best I can get is around 230-240.....good shafts make the difference. The fitter said he feels that he can get me another ten yards.

I too have been using a 44" shaft for several years now. I know that i'm giving up a few yards, but am enjoying playing out of the fairway or light rough. By the way Chuck, when your getting fit for your new driver, take a look at the TSi 1 in addition to the TSi 2.

I went back to 44” and changed the head weight to 15g. I had too steep of a downswing. My best with 44.5” is 275. My best with 44” is 265. 250 with 43.5”. I find the fairway more often with 43.5
and 44”.

The new drivers all seem to be playing at 45 1/2" as a standard, and I've heard that some are now pushing 46". It makes sense that a perfect swing with a longer shaft at the same swing speed will result in a longer drive, but none of us are perfect every swing. Lesson from the pros - they hit the sweet spot more than any of us hacks and most of them are using 45" or less drivers. Not only do you gain accuracy but many times there is no difference in length. I was fitted to 45 1/2" TS2 with the Tensei Blue when they first came out, and after 3 month switched to one of my 915 shafts playing at 45" and experienced more control and very little loss of yards. I sold the Tensei and now have 2 shafts playing at 45" (GD AD VR and Ventus Blue) and one at 45 1/2" (Kuro Kage). Pretty much settled in with the GD shaft and with midsize grip and added 2 grams to the clubhead I'm hovering between D1 and D2. Gained a bit of distance (less spin with the GD helps) and always find the fairways. And sometimes my ball is there too!!!