I own a Gulyassy custom with SPTX shafts, planning to post some pics and maybe write a review at some point, but seeing no one has replied to your question, let me say a few words. Needless to say, what makes this shaft so exceptional is the looong taper (18 inches straight?) that would be impossibly whippy if the wood weren't soaked in Mike's Shaft Freeze. Whether or not it qualifies as low-deflection shaft is hard for me to tell: using side spin, the difference to e.g. my 20-year-old Southwest birdseye maple pro taper shaft is negligible at best - which doesn't mean it's impossible to handle, far from it. It's less gradual for sure: similar to other LD shafts, one won't miss slightly mishit center ball shots (= no intention of playing side spin, merely unclean center ball - probably any LD shaft's greatest but unknown advantage to the novice, IMHO, that they're so forgiving in this respect). The SPTX feels different, maybe whippy, easy to overcook shots, probably best used by expert players, I wouldn't recommend it to a beginner. I'd even go so far as to say it feels a bit weird, especially due to the Shaft Freeze a bit CueTec-like, but the fact remains, I was able to do one of my daily regimen exercises as well and quickly as on average, if not better, and won a Round Robin tournament (winning all matches despite spotting heavy handicaps), all on Day 1 (= the day I got the cue). In other words, I'm old-timey, used to touching wood (the Shaft Freeze feels "plastified"), but there's nothing wrong with the way the cue hits - especially playing little or no english, it hits so solid, it's hard to believe it's the same cue/type of shaft that, when one knocks it on its side, wobbles like crazy. Now, the Shaft Freeze is a problem in our at this time of the year rather humid climate: it sticks to my skin, almost burns it. But the taper is such that, when I used a glove on Day 2 (I usually don't like using gloves, and never do), I was amazed how I could use a virtually airtight bridge, control speed (which with a glove, I tend to have a problem with normally) and follow through no end. That combination, in a humid climate, may in fact be ideal. Now, to end this with, I have no idea what this type of shaft will do for other cues - I could only try it on that custom Gulyassy (he uses his own type of joint pin). It's a fascinating concept for sure, and a more modern-minded but experienced player may feel very much at home with it. But note it's certainly no 341-2 (stiff, hollow also in terms of hit and feel) or the like - rather the contrary (provides the through-vibration of a whip, if in the best sense, truly a shaft to generate power with, and make the cue ball dance). Not sure this helps?
Greetings from Switzerland, David.
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