Due to the shape, the string stays away from the response pads, thus less friction and a little bit more spin time. KK bearings are nice to have but I donāt see myself buying a bearing by itself anytime soon, but if a yoyo already has one, Iāll take it!
I feel like it gives a little more stability, but there is less room for layers of string to flow as the stings gather in the center of the concave bottom. I used one for a mini motu years ago when I was just getting started and though it was helpful, expecially with the o-ring response. With a good throw and flat or sightly recessed silicone response, flat bearings work fine for me.
Some people say they donāt make a difference but I do. Konkave means that they have an angle going inwards on either side meeting in the middle of the outer bearing. As you can imagine, when the string is in that dip even if you do a lot of tricks it will stay there. This centers the string preventing the string to touch the side of the yoyo and slow it down. As a result of this they will also probably make your yoyo be more stable, as in spin longer. I also notice that Concave (the real spelling) seem to be higher quality bearings but that doesnāt mean they always are. Also some are very expensive but do their job as a konkave but not at being extra expensive ( over 30$) and I am not naming names on those but you can figure it out if you search for them.
since i recently switched to fat/thick stringsā¦ most of the kk/center trac/crucial groove ( i have all three) sometimes catches the throw in the middle of layered string tricks. I noticed this for all three of these bearings.
So i switched to flatsā¦ i donāt really need the kk/ct/cg anymore to help with my throwing and keeping the string dead centerā¦ with the flats ā¦ the fat/thick string doesnāt get tangled as muchā¦ and i donāt get the throw returning back in a middle of a trick or slack trick ā¦ which can get annoying and painful
I would say that if you are using regular 100% poly then you are good to go with the kk/ct/cg and you can even try the fat/thick string on the kk/ct/cg ā¦ but for me it didnāt really workā¦ so i switched to flatsā¦
now this could be different for someone else ā¦ this is just an example of what happened to me
bottom line is, if you can play, you can play on anything
I prefer concave for 5A, flat for 1A
the biggest impact it does for me itās about how the yoyo feels on the string, with a concave bearing, it feels heavier, more solid than it does with a flat.
people are going to tell you things about how some might open up the loop in suicides more, or snag more, again, if you can play, you can play on whatever. If you need a specific equipment in order to be able to play, youāre just not good enough and all you need is some practice.
When you begin, concave bearings will make your spin times a bit longer and help you with the alignment, but you shouldnāt get used to them because itāll raise problems later down the road.
use whatever, mix it up, some yoyos are better with KK on, some will feel better with flats.
Buy the KK if you have extra cash and are willing to try something new. Donāt buy it if you think it magically solves spin time problems, stability, and the straightness of your throw. Those all come with practice.
i think some people didnāt quite understand what i was saying ā¦
I was saying that in my experienceā¦ with FAT strings and KK bearingā¦ specially the new Toxic strings ā¦ with combination of KK or center trac or crucial ā¦ the throw returns or SNAGS in the middle of a trick because of the thicker string (obviously its the string and has absolutely nothing to do with, whether or not you can play or not)
kkās come in a, c, d, and metric sizes. the oxy iv i had took a c sized kk (when installed correctly w/ the axle system) - even though the stock bearinā was metric.
kkās are manufactured konkave. they are not flat originally, and then grinded down. this induces undue stress on the bearinā and limits life.
kkās are stainless steel, and w/ proper care, will not rust out or deform due to ānaturalā corrosion.
kkās center the string by design. Mr. Difeo was the first to pioneer this design and has a patent.
kkās also help correct the gyroscopic effect along the x axis of play - some poorly designed/cheaply manufactured yo yos suffer from this phenomina.
will they make you a better yo yoer - no. but like unresponsive play, it may make the playinā experience a lilā more consistent.
experience the dif-ference for yourselfā¦dif-e-yo.