Hey I was wondering if I could put a Center Trac "Or Konkave"into a Duncan Freehand Zero.I also like to know of any mods you guys like.Thanks ;D

They do make a-sized CT/KK bearings. I have a CT in one of my FHZ’s and love it.

Does it do just as good or better than switching spacers and taking out pads? Could I like put weight rings on it?

putting a KK in and adding weight/removing response would do two totaly different things to a yoyo.
A KK is going to change the way the yoyo rolls off the string when you throw. Personaly I think this is the largest change.
It will also make the yoyo more stable.
widening the gap with spacers will make it less grabby during string tricks but will take away some of the rpms you get on your throw.
Removing pads will both make the yoyo smoother(less grabby) during string tricks, and reduce the rpms on the throw. Will also make the yoyo bind differnt.
Adding weight depending on how you add it will change things, and makeing the yoyo heavyer is going to be the main differance, but it will have more seconds of spintime per rpm loss. Could make the yoyo more stable, and may make the binds loose or the throws slide. Will most likly add vibe.
I would think that most people adding a KK, would run only one duncan pad, run the yoyo with the widest spacer, or shims to shim it out. If you want it to weigh more you can put rubber oring under the caps, or try to find some of those aftermarket weight ring kits. II, and throwdown both made some, but don’t anymore I belive. Probably a bst purches.

What are rpms sorry ;D

rotation per minute

Oh thanks.

What about puting a center trac in?

same as a KK.