Gap width and thoughts on the Hitman


So, I got into yo-yoing back in march – first at the encouragement of my 10 yr old son, and since stuck with it because the activity was (and still is) showing some very positive signs in rehab’ing my right elbow (which had to be reconstructed after a cycling accident).
Any-hoo, for about the past two months I’ve been using a Hitman almost exclusively. I purchased it new and installed red shims. Now that the o-rings are worn nearly flush, I’m guessing the gap width with red shims is somewhere close to 4 mm.

First, I must say, YoyoJam should really consider shipping shims with the Hitman. Stock, the gap is way too narrow. With shims, it’s great. Also, it only gets better as the o-rings wear in (which is nice because o-rings seem to last way longer than flowable silicone).

Today, I was fooling around with it and put two sets of shims in it, one red and one gray. This brings the total gap width to very nearly the width of the bearing. I don’t have anything to measure it with, but i’m guessing it is somewhere between 4.5 and 5 mm. I expected this to reduce response to probably past the limit of playability. I also expected this to reduce stability and possibly spin-time.

However, none of this happened. Response remained exactly as before, which is to say excellent (I use 100% poly highlights – I rarely miss a bind). Stability seemed unaffected – there was no tilt on good throws. (I will say that I needed to adjust the axle to reduce vibe – this was something I also had to do with one set of shims installed). Spin time also seems unaffected. In fact, if anything it has increased. My only explanation here is that increasing the gap actually increases the number of times the string wraps around the axle. This is because the radius of the wrap zone increases more slowly compared to that of a narrow gap (because the string is wrapping over itself at a slower rate – confusing to describe, but makes perfect since looking at the yoyo). An increase in number of wraps seems to increase torque and, therefore, momentum. Again, this is just what seems to be happening. Spin time has not changed so drastically that I know this to be true.

So none of those things seem to have changed negatively, or really even significantly. However, I’ve gained all the added benefits of a wide gap – i.e. more string layers without slowing down the yoyo, easier to land on the string, less likely to snag during a whip or return after releasing a whip (although, in all honesty, once the o-rings wore down, this really wasn’t a problem).

So here’s my question. I know a lot of people have done research into the various aspects of a yoyo (bearing size, rim weight, etc.). What do we know about gap width? I thought I understood gap width meant less response; however, it seems that within a certain margin, gap width doesn’t really affect response at all.