I recently overhauled my Shimano Tiagra hubs (cup & cone), following instructions from Zinn's book. While the wheels were off the bike I tightened the cone/locknut until there was a slight amount of axle play and when I held it by the axle and gave it a spin, the wheel rolled freely without any detectable resistance. I put the front wheel in the fork, tightened the skewer, gave the wheel a spin and...I got a mush, crunchy sort of sound. It wasn't awful but it seemed lik something was wrong. The wheel was still spinning freely however--I couldn't detect any resistance and it rolled for a nice long time.

I removed the wheel, loosened the cone a bit and still got the crunchy sound when the wheel went in the fork, so I repeated the process. By the time the sound went away, the axle was clearly too loose, even with the skewer closed. At this point I think it could be one of two things:

1. I put too much grease in the races and/or the grease is still too "fresh" (is that even a thing?) and is making a sound. I don't feel like I put too much grease in there...there was enough to the point where I was able to press the bearings down into it and they wouldn't go anywhere.

2. I'm just not being precise enough with my cup and cone adjustment. Is the sweet spot really that elusive? I feel like I was pretty close, but this is my first time doing it so I could be wrong.

Let me know what you think. Maybe there's something I'm not thinking of. Thank you!

My bet is: dirt, or debris, or a corn of sand, or similar. For most of us it is hardly ever possible to really work clean enough and it is common to hear such sound after hub overhaul. I you are sure you assembled correctly, you just want to ride on the wheel, those sounds often disappear

I pick #2

Grease doesn't break in, it's fine when you first use it, and only gets worse over time (don't sweat it's a v-e-r-y l-o-n-g s-l-o-w process).

So either you left some dirt or grit in the hub, or lack touch. Try this, set the wheel up very slightly loose, with one cone and locknut tight, and one only hand tight so you can adjust it. Mount the wheel, and close the QR not quite as tight as you would for riding. Feel for plat at the rim, if you can't feel any back the cone out a hair until you just do. Now tighten back till the play is gone, but no more. Bring the locknut up and lock them together, shy of full tight. Reset the QR tension to riding level, and check the wheel. If needed you can do a final tweak by either bringing the cone out, or locknut in as needed when you do the final tighten.

BTW- If there's a material change in cone adjustment in or out of the fork, there's a chance that your fork ends aren't parallel. That bows the axle when you close increasing baring load much more than the QRs compression alone would.

Thanks for your input everyone. There may be some grit in the hub still as I was unable to remove the freehub body to clean inside the drive-side bearing races (a 10mm hex key and all my muscle couldn't get it to budge). I'm curious though: if the grit was there to begin with, how come I'm just hearing the sound now after I've cleaned everything else?

Also, how will I know if the rear hub is doing the same thing? The sound isn't loud enough that I would be able to hear it over the freehub ratcheting or even the chain running through the RD...should I just lock the rear wheel in without the chain until I know the hub is properly adjusted?

Easy way to know if the noise is in the freehub, or on the hub's bearings. Mount the wheel mirrored with the cassette on the left, and the chain below the hub. Spin the wheel and the freehub will spin with it. Then put your finger against the freehub so it stops spinning (spin the wheel in the right direction so this works).

If you hear the grit when the freehub is spinning with the wheel, the bearings you packed are dirty, or too tight. If you only hear the grit when you hold he freehub, then the bearings are fine, but the freehub is gritty.

Remove the FH to clean the race?
Why?

Try using a Qtip

Just so I can actually see that it's spotless in there. I was going to use a Q-tip to clean the races on that side but was afraid that the dirty grease in there would pull some cotton off the swab and just create a greasy, cottony mess that would be more difficult to clean. I'll give it a whirl, though.

Thanks for the tip, FB...I guess that's a pretty obvious solution. My common sense just isn't working today

Most freehub systems' bearings are outboard, on the left side of the hub, and right side of the freehub. There's nothing more that would be accessible if you remove the freehub from the shell. The freehub does have it's own bearings and the ratchet mechanism but it comes off as a closed module so you wont gain anything except the ability to toss it into solvent without making a mess.

BTW- one place that people sometimes forget to clean is the non-contact area down the length of the axle and inside of the hub. If you open the bearings again, be sure to push a cotton ball or piece of rag or paper towel through the hub with a stick. It doesn't affect function, but dirt there can sometimes make noise.