The Fat Shaft is stiffer and is still a pro taper, but it does deflect a bit more. It's still lower deflection then a stock shaft though. I might have mine taken down to 13mm ( instead of 13.20 ) while keeping the stiffer taper, 13.20mm maybe a bit much. For me I just wanted a 314-2 that was a bit stiffer, so taking it down to 13mm may be close and hopefully lower the deflection a tad.