Ok I’ll add this just to help confuse the question.
Hummingbird and Tiss hummingbird. The TISS is 1.5 or 2 gr heavier yet it seems to ‘float’ more than the HB
Then I tried the Bowl and the 000. both almost the same size, but the Bowl being heavier by about 2 grams. The 000 seems to ‘float’ more then the Bowl.
The only thing that might make sense to me is the rim weight biased throw has more ‘float’
I’m baffled as well.
@FiveIronBrian, @wolfwithamelon and @MarkD
I’m prepared to believe that it could all just be in my head. Lol.
You are probably quite right; more rim weight probably does not lessen maneuverability.
That’s actually a bit of relief for me because I have feared bimetals a little because of my earlier reason.
Do you not have any bimetals? Step one: GIT SUM
I’ve owned several in the past.
On the other hand, the feeling on the throw is not in your head. For their weight, bimetals will feel heavier and unwind slower. Once you get it going though, you’re good to go!
Then why, oh why do manufacturers intentionally add centreweight to their designs?? What quality does it contribute to a yoyo design?
I don’t buy the argument that it makes the yoyo more unstable so it makes you a smoother player, that really is a bit dumb.
So what quality does it add?? There really must be something desirable it achieves…
Here’s a design with some intentional centreweight; the C3 Radius. That wide and slightly raised hub increases it. It is a superb player.
What does its centreweight add to its performance??
My take:
The ability to change direction is governed by the moment of the body. The rotational moment describes the resistance to change of direction about a particular axis. I think this is what we are talking about.
Looking at the equations for a disc vs. a ring, we see that the ring has two times the resistance to movement than the disc. I think this describes the difference between the two types of yo-yo’s. The rings will resist changes in direction twice as much as the body. In bi-metals, this is accentuated by making the rings relatively more massive and more dense. The more extreme the rim-weighting of the rings, the more pronounced this effect will be. You can see that by adding center weight to the disc (the center); the effect of the rings on rotational moment can be minimized by maximizing the Disc mass.
Ring: 1/2(mr)^2 Disc: 1/4(mr)^2
What the Draupnir does perfectly, is combine rings that seems to have an equal moment to the body it is mated to. This makes it combine the best of both the SS rings as well as the 7075 body. This also serves to hide any weaknesses that the two materials might combine to expose. It is quick, light; spins forever and has amazing stability for the weight it has. You do not feel the rings. It is zen…
I think a lot of it is driven by aesthetics, same reason you don’t see tapped-through axles any more.
Additionally, a flat hub doesn’t add that much centerweight if the axle is short or if the material allows less distance between the hub and axle tap. The radius has an 8mm axle and is made of 7075, so that flat hub is adding less weight than you’d think.
On the other hand, having too much rim-weight can be bad for some play styles. The yoyo takes longer to get to the bottom of the string, it can feel “bad” on the throw
In short, it’s a trade-off.
Yes it does, an this is intentional in the design.
Shion himself describes the Radius in this way:
‘The qualities I look for in a yo-yo include maneuverability, balanced smoothness and responsiveness and a powerful spin. We shaved 2 grams off the Krown, so in order to preserve spinning power we reshaped it to the round stepped straight profile. With a little more weight concentrated in the inner body, it looks heavier than it feels, and moves exactly as you’d expect.’ (emphasis added)
It’s interesting to experiment with one drop’s side effects. You can feel what changing a few grams in the center can do.
Yes, provided you switch to brass which is verrry heavy.
I wonder how much “a little more” is in this case. But yeah, if their goal is to reduce the rim weight (thereby reducing kickback and what not) then that’s a great place to add the weight back.
Yet another thing the MMC is great for. I should track down some ultralights, only have the brass MMC SEs and some energy domes right now.
Except for the properties I discussed in relation stability, and how that relates to maneuverability, at least as I discussed it above. I think that is were a perceptible difference lies, and is a main element that yo-yo designers play around with.
If their goal was to reduce rim weight, why not just take more off the rims? 
The design is actually loaded with weight anywhere that isn’t the rim. There is weight concentrated a little further back from the rim, another fairly thick load right next to the hub, and then the flat hub itself.
I was thinking more about what you said about more centreweighted yoyos become off plane more but are easier to put back on plane.
That’s true, but how is that advantageous? Isn’t better to have a yoyo that starts on plane and stays on plane? Is a yoyo tipping all over the place useful for anything but gyro tricks?
What I’m getting about centre weight here so far just sounds like it’s pretty much bad.
What I’m getting from my C3 Radius is that centreweight can be very good indeed. Even suitable for a 2x world champion.
I have no idea how to reconcile these things.
Well, I think it’s really difficult to account for every design constraint at once - I’m sure the result has the right mix of rim weight, total weight, center weight, etc for Shion. It doesn’t need to be maximized in any one area (and probably shouldn’t be) to be a good yoyo. I suppose this is one reason why monometals are still really common at all levels of play.
It’s a matter of control, or more how responsive the yo-yo is to control inputs. It’s a trade-off. I think it’s safe to say that for most competitors, it’s better to have the yo-yo remain stable, and track on it’s own as much as possible. However, perhaps Shion prefers to be more in control, and values more the ability to make adjustments to how the yo-yo is tracking, over having the yo-yo being more resistant to plane changes.
For casual play, less stability can make the yo-yo seem like it has more character. Obviously, super rim weighted yo-yos are not the only yo-yos throwers enjoy, or nobody would be still be buying all the alternatives!
I have thought of an analogy: traction control and other computer assists in cars. For most people they offer greater performance, but often take some of the fun out of driving. Not that I have much experience with that, but I like watching/reading about it!
It would be great if @walterC3 would chime in here.
I was thinking the same thing, or really any yo-yo designer. Well, in addition to you, that is… 
