this mod will make your nankai freecoaster smoother and stronger. you will need a nankai wrench, a big adjustable wrench for lock nuts, some thick grease and some extra ball bearings. the bearings inside the driver on my 11t are bigger than the bearings inside the shell, so make sure you get the right sizes.
the bearings that come in a Nankai hub look something like this:
we are basically going to eliminate those cages to make room for more bearings to make the hub smoother and stronger. push the bearings out of the metal cages inside the hub so you have nothing but loose ball bearings.
actually, you could probably do this to any unsealed part and get better performance with it. those of you who are plagued with an unsealed bottom bracket, take note.
1. take your hub apart. "glue" all the bearings to the cones with grease, not the hub shell. i think you need 17 on each side of the shell and 10 in the driver? do the right side first- push all the balls in close around the inner part of the driver, not out along the sides of the dust cover. the driver will not fit right in the hub shell if the bearings are too far out.
2. secure the driver so it doesnt shift, causing all the bearings to fall out. I like to put the drive-side shell bearings in first, then thread the clutch in. i wrap a rubber band around a spoke and wrap that around the driver to keep it from un-threading itself and falling out.
3. arrange the left-side hub bearings. make sure the cone, lock nut and outter nut are all tight.
4. carefully slide the axle with the cone assembly in place and set the axle upright on the floor/bench so it doesnt fall back out. if the axle doesnt go in all the way, either you have too many bearings on the cone or the bearings have shifted and are not fitting into the shell correctly.
5. grease up the outer race of the driver. the driver bearings in my 11t driver are slightly larger than the hub body bearings. make sure you are using the correct size bearings! i put a little o-ring under the cone nut to keep some of the dust out. drop the bearings in around the axle with lots of grease and thread the right side cone nut on slowly.
6. now take that rubber band off. tension the cone nut and tighten the lock nut against it. a Nankai wrench is absolutely neccessary for the finishing touches.
lemme know if you have questions.