Is there any way to distiguish between the sealed bearing version with the cup and cone? Someone is selling them but is vague on the details and the pictures they sent aren't that big.

https://www.businesscycles.com/thub-suz.htm

They look exactly the same on here. Also, are there any Pro Max hubs that are threaded just for freewheel on both sides? Thanks.

No on the free/free - these are track hubs, afterall.

Do you mean distinguish just from looking at them?

Ask the seller if there is an NJS stamp on them (assuming they are 36 hole).
If there is, then those are cup and cone.

if it's fix/fix, then it's a loose ball.
if it's fix/free it's most likely a SB. (i've never seen a fix/free loose ball pro max)
otherwise the visual differences are really subtle.

the SBs dust covers are more rounded, the loose balls' are flatter.
or measure the axle diameters. The SB's are 9.5mm front and back, the loose balls have a 9mm in front and a 10mm in back

+1 on the fix/fix vs. fix/free

I recently got a set of the loose ball fix/fix and they are insanely smooth. Highly recommended.

By the way, you can thread a freewheel on a hub with fixed threads.

by the way, suzue made a small run of fix/fix sealed bearing hubs. Just be aware of that.

Ok, I they're on their way and I have some questions about their measurements. I'm using the calculator at: https://www.bikeschool.com/spokes/index.cgi Business cycles says the flange diameter is 67mm. Wouldn't the hub center to flange center just be half of the flange diameter? So 33? And the hub spoke dia, is that ok at 2.5? Thanks.

Can anyone confirm these numbers? Thanks.

I used spokecalc for my loose bearing which apparently are the same dimensions as the sealed version. I used 67 for the flange diameter. Center to left and right flange on rear was 32 and 35.5 for front.

Hope that helps.