are the bearings under the knobs one universal size?

No.

No.

thank you.

Actually, a better answer is, "not always, almost never, unless there are special circumstances," LOL.

So, that begs the question.....which two are you looking to switch out?

Bearings are sold by ID(inside diameter)x OD (outside diameter)x W (width/thickness) If you don't have a caliper Autozone or someone like that should be able to measure them for you. At one time, I had a chart you could lay the bearing on to measure but I can't lay my hands on it. If I run across I'll post it to share.

ive got calipers to measure bearings. the only info i had about the bearings for sale were they were stock revo 2010 stx knob bearings. for $10 i should have taken a chance, i just have too much crap sitting around already.

Most Abu stuff is interchangeable.

Most Abu stuff is interchangeable.

x2

Also, some of the Abu stuff is interchangeable with some of the newer Pflueger stuff. I'm running an aluminum Revo knob and bearings on my Supreme XT spinning reel.

i was going to a Daiwa carbon handle and using some off brand foam knobs.

You're on your own there, man. For some reason, 3mm sticks in my head for ID on Daiwa knob bearings. You better measure to be sure.