I'm using the carbon express nocks on a stock bear super mag string, which bear told me was 16 strands of fast flight and that the center serving thickness would not matter even though I asked for it as well.

The nocks fit very tight on the serving. I have to really snap them on. Turning to bow so the arrow points hanging down from the string, no amount of tapping the string will cause them to fall.

Too tight, right?

What's the best way of adjusting the nocks to fit better? Simply spread them manually, or sand them with something?

How do you know when you have the perfect fit?

I'm concerned with excess noise and loss of energy the tight nocks surely bring to the party. Any input is greatly appreciated

I would use a nail file or piece of sandpaper and shave off enough of the nock so that the arrow will fall off the string with a lite tap while the arrow is pointed straight down.

Other options:
Use a smaller diameter serving.
Cut down on the strands. Maybe cut back one strand from each bundle and reserve.

I placed my nocks in very hot water and then when they were somewhat pliable pryed them apart just a bit and dipped them in cold water. It has worked well for me.

I like your first option best, because I actually have the stuff to do it

Thanks.

check my post from a few seconds before yours. its easy and if you get the gap too wide you can just start over and close them up a bit. Use caution, I'm not real bright and scalded the heck out of my fingers the first time!

Ive done that trick quite a bit. Ill also take myfingers and bend them out several times to losen them. That only works to fine adjust them. I like my arrows to hold on just enough to keep the arrow on the string. I test mine by snapping on an arrow, hold the bow where it faces down, and tap the string. If the arrow falls off, its where i like it. If it stays on, I losen the nocks more.

I use the boiling water trick more for reducing the size of the nock.

Thanks guys, I didn't see the follow up posts.

Only way I have of heating the nocks here at my office is heating up a coffee mug of water in the microwave. That should work

I've done both the hot water & the sanding thing. If it just a little tight, I'll sand. If I'd have to remove too much, I'll use boiling water.

That's where I'm at. Tried the nail file, I'd have to remove way too much to have a viable nock left. Will try the hot water treatment and see where that gets me.