Hi all!
I’ve tried to google information on how to service a Roval 321 hub (rim brake) without success. Specifically I’d like to know the specifications for the hub bearings and how to remove and install them properly. Surely somebody must have attempted this before! 
Any pointers?
Did these wheels come with ceramic speed bearings? If so, maybe start here and/or send an email?
If you look at the bearings, you will see that they are marked with the size.
There are many bearing removal and installation tools.
Hi all!
I’ve tried to google information on how to service a Roval 321 hub (rim brake) without success. Specifically I’d like to know the specifications for the hub bearings and how to remove and install them properly. Surely somebody must have attempted this before!
Any pointers?
Spec refers to the 321 hub using DT Swiss 240 hub star ratchet internals. I’d assume this is the legacy 240 rear hub rather than the current 240 EXP. There are plenty of online resources outlining DT 240 hub servicing and parts.
You can just pull off the freehub/end cap by hand to get to the star ratchets and springs. The inner ratchet ring requires a proprietary tool for removal and access to the DS bearing. The axle comes out from the NDS and you can access the bearing directly.
You can service the bearings by popping the cap off the non-drive side.
Stick something larger than the axil hole to pop off the drive side cap and free hub, you may have to vise it and pull the cap off manually.
While inside you can peal with a dental pick, the dust caps to each bearing casing and then flush and lube as preferred or replace.
while you at it buy a 54T ratchet replacement instead of the standard 18T
If you run into any hiccups you can just YouTube how to service a rear DT Swiss 240 hub. the hubs are the non-Exp version.