I have a DV888 unresponsive coming in possibly tomorrow. I want to swap it’s SPEC bearing to Center Trac. Will I have to replace the old axle on the yoyo using SPEC, in order to fit the new Center Trac? Thanks!
EDIT: Wait, Center Trac is supposed to be better than SPEC right?
The unresponsive DV888 should come with the regular width SPEC bearing (correct me of I’m wrong), so it would be a direct swap with your CT bearing (or any other Size C bearing) because the width would be the same. Changing the axle would not be necessary
As for whether the flat SPEC or CT is better, that would just be personal preference 
I know the CT bearing helps center the string so it doesn’t touch the sides, I’m not sure what the SPEC one helps out on, do you know?
The SPEC is a flat bearing, and some people prefer it when doing tricks that require many string layers. You’ll have both bearings, so you should just play with each for a few days and find out what your own personal preferences are. Your preference for flat vs grooved vs CT bearings can even change depending on which yoyo you’re using.
Just have fun and experiment!
Some like centering bearings, some like them flat, there’s no better. In fact I think some throws go better with a flat one, while others go better with centering (but that’s just me).
The number of ball bearings inside is something that usually makes a bearing overall better, so if your CT bearing is 10ball it will most likely spin longer and smoother than a SPEC 8 ball bearing. I don’t know the default bearing of the DV888 unresponsive, I think it’s an 8 ball flat.
i bought the yye shutter specifically to get the CT bearing, and bought a gold CT for my markmont classic. a month later im installing a gold flat bearing in my mmc and i like it SO much more than any concave ive played. i get the concept behind center tracs, and thought it would be ideal, but im not ashamed to say that in my experience flat bearings play better.