Razor ecosmart Metro: How many balls in rear wheel bearings?

The package to order from a west coast seller has 20 balls in each package, front and rear. I took apart a rear hub that I believe has never been taken apart and I have 9 balls on each side. Is that correct?
I guess maybe the package gives you an extra two.

Thanks,
orlbuzz

Traditional bicycle hubs use ten 3/16" balls on each side of the front hub, and nine 1/4" balls on each side of the rear hub. Whether your scooter uses ordinary bicycle hubs I don't know, but they look pretty regular to me.

If the bearings are rough or lumpy feeling, the cones are probably pitted, and you'll need replacements for those too. They have to match the thread pitch of your axles, and the inside diameters of the hub dust caps.

This is the kind of problem that bike service shops are really helpful with.

Thank you Chalo!
I do have 9 balls for each side of the rear hub.
Those are 16" bicycle wheels on the Metro. The shop on the west coast sells 5mm and 6mm balls. The six may just be 1/4" because that equals 6.35mm. I don't need new ones now though. The cones and balls look great. This scooter is a 2014 but it couldn't have been ridden much, it is just in too good condition. The older fellow I bought it from told me he rode it once and it has set for three years. He was the second owner.
I put 15 AH batteries in and geared it down. That is still not enough for these Tennessee hills, so I am upgrading the motor to 800 W and 1000 W controller. Since i had the scooter apart, I decided to clean and adjust the axle while I had it out.
Thanks again!
orlbuzz (Gary)