I would love to see OD make a SE system for D bearing yoyos that could be interchanged with their C-bearing throws. This would really showcase the differences between C & D-bearings without conflicting variables.
I know the pads are generally different based on the bearing, but would 19mm pads be an issue with a D bearing?
yeah, the bearings have different inner and outer diameters. First you would need two different side effects one for C and one for D, and then youād also have to account for the gap that would be exposed:
(I forget who I stole this base image from sorryā¦)
basically the D bearing would not be as large as the C bearing, and so youād expose a bit of the gap:
solve this problem and you can probably do it, maybe a 3d printed insert or something who knows
I second this 
When I came back to throwing last year and heard of OD for the first time, I instantly thought it was a bearing based gimmick.
I was so shocked when I saw no small bearing option 
I feel like a lot of debates in ā09 were SB vs LB.
What did I miss? Why have Ds vanished from major line ups?
Not to mention A bearings. Where they at?
Plus
Wouldnāt it be interchangeable from a design standpoint with these Side effect guts?
YYF literally used to switch out for an A and keep it moving.
This topic alone has made me get into yo-yo design just to understand it more for myself.
And maybe drop a batch of yoyos that just donāt exist right now.
If I can get the casholo for it 
Yall are in luck! Freshly dirty seems to have made an axle system that works with both C and D bearings. Its called the stem.
Canāt wait to see these at nats itās on my list for sure
Im excited too! Very curious how that works! Freshly dirty always comes up with some neat stuff
The stem system FD has is so cool. I canāt wait till it drops
Iāve got to play with some protos at club and itās just a fun system.
Not Side Effects. But ZGRT had a swappable system in the Albrije.
DOOOPE canāt wait to get my hands on that
Youād need to change the entire bearing seat between bearing swaps. You could design a D bearing yoyo and just randomly have it use 19mm pads meant for C bearing yoyos if you really felt like it, but you still need the actual bearing seat to accommodate the smaller bearing.
The EX series of yoyos from yoyojoker accomplished this by doing whatās esssentially a more elaborate version of Duncan mod spacers.
Duncan also did the Flipside which was an interesting approach, where the spacer acted as both the bearing post and the bearing seat. A bearings are the same inner diameter as D bearings. Since side effects need to go through the yoyo from the outside, you couldnāt really accomplish this with just a single piece, although you could maybe have a spacer designed to act as a D bearing seat that rests within an OD C bearing seat. Itād probably be very hard to do this in a way that results in a smooth yoyo, and youāre still going to have to put up with the response being so far away from the bearing, which makes both throws and binds feel really weird.
I doubt OD would ever make something like this, but it could be an interesting thing for a modder to make, since you could just turn a C bearing side effect to have a smaller post size for the D bearing, and then make some kind of spacer to fit into existing bearing seat. Itād probably work better for A bearings than D bearings though, because the more narrow width of A bearings would give you actual room to work with for creating the spacer. Although I guess there technically wouldnāt be a problem with just extending the gap further. But considering youāre already going to be dealing with a huge gap between the outer diameter of the D bearing and the C bearing response pads, widening the gap of the yoyo further sounds like a bad idea in terms of having a yoyo thatās actually nice to play.
the most difficult part with any of these systems is getting the halves to be perfectly aligned otherwise you end up with vibe. Iām not sure how FD has dont it but the stem system works really well in this regard unlike cabal guts or even the alebrije parts that if the halves arenāt perfectly aligned or seat completely flat you get pulse vibe super easily.
Even the duncan mod spacers can get viby easily if they arenāt fit just right.
You have a great point. Precision, body material and weight distribution are key for this type of components.
Iām guessing itās just a lot easier with all machined pieces. The issue with mod spacers is being old injection molded plastic, used on injection molded plastic yoyos. And the issue with the Alebrije being that the yoyo halves are made out of wood.
Yoyojoker EX system stuff was smooth, Mowl kinda uses the same setup for the MRL and itās always smooth. I think Tom Kuhn did something like that recently with the SBX and Iād bet those are all completely smooth.
Side effects are definitely a different story though, but I donāt think thereās really any issues any more with just getting smooth yoyos that can swap bearing sizes. Although I guess even if given a smooth consumer product with a low B grade rate, systems with more moving parts probably arenāt gonna be worth it for people obsessed over nail vibe. Just more that can go wrong through user error.
Iām just relaying my experience with various designs Iāve played and my own struggles trying to print smooth yoyos. its a challenge that personally I havenāt got to the point Iām happy with in my own work so far.
Personally, I love all the cool designs that use a system like this and i hope to see more of them as time goes on. As we see with yoyo joker and various other older designs this concept isnāt new but its definitely evolving with better precision and new materials to play with.
One of the neat yoyos you dont even realize but has a sort of spacer system like this is the yoyoformula D1 is just delrin halves with a neat spacer system for the hub. Its fun when you open a yoyo and see what is holding the whole thing together.
Iām sorry, but I donāt have the best engineering mind. Can you give me some perspective of whatās going on in this diagram (i.e. zoom out)?
To clarify, by interchangeable, I meant have a size D side effect than could be popped into a yoyo meant for size C SEs - not one SE rule them all.
Forgive me since Iām new to One Drop (and yoyo design in general), but donāt the SEs act as both the bearing posts & seat for SE yoyos?
in the drawing the white parts on the left/right are the yoyo halves, the gold areas are grooves cut in for the bearing and the response pad.
a c bearing is approximately 3.XXmm larger outer diameter than the D bearing, using a D bearing in a yoyo half designed to accomodate a C bearing would result in a large gap around the outer edge of the bearing that string would be able to drift into.
the side effect acts as the bearing post, the seat is the part of the yoyo half the bearing rests on.
FD Stem System dropping this weekend at Nationals looks like this concept @Saltman360
They are more like cabal guts.
Thank you so much for taking the time to explain this. I ask because even though Iām a novice in yoyo design, I genuinely want to understand.
I couldnāt find much about the anatomy of SEs (probably because their genius is their simplicity), so I was mostly guessing from the looks of my Reboot. The bearing sits almost exactly perpendicular on the SEā¦
That clearly wouldnāt have made sense, if I would have paid attention to the fact that that part doesnāt protrude to the inside of the yoyo. To be fair, it doesnāt look like thereās much of a seat on the Reboot:
I didnāt know that little groove was the seat originally. Now I see why others have said this would likely be a job for modders, as that certainly complicates things (besides the gap that the string could get caught in). I get why a different design all together would be better than SEs to accomplish that goal. Thanks for bearing with me!
Is there some variance from brand to brand? The data I found showed a difference of 1.7mm (11mm for D; 12.7 for C). Not trying to āfact checkā you or anything - again, just genuinely curious since Iām looking to get into design at some point.
