I am in the process of buying a new wheelset for a fixed gear bike. There are so many to choose from that it's hard to decide. One thing I've noticed is some wheels have hollow axles, while others are solid. Would it be okay to use hollow axles without quick-release skewers (axle nuts instead)? Also, is it possible to change the axle in a sealed bearing hub? If so, how difficult is that?

Thanks.

No, you can't use a hollow axle together with axle nuts, because it isn't long enough. Hollow axles ends flush with the outside dropout faces, or slightly shorter, so there'll be nothing for the nuts to thread on to.
You might be able to use a rear hollow axle as a front nutted, or an extra long hollow tandem axle or something like that, but it doesn't seem worth the trouble.

With sealed bearing I assume you mean cartridge bearing . Those tend to use proprietary axles, that aren't just a simple rod. And they usually taper down to the dropouts and things like that. There's probably some cartridge hubs out there where the axle can be replaced with something else entirely with a minimum of drama, but I haven't come across any yet.

Thanks.

However, I was looking at some wheels on velomine.com and I noticed this:



It's a hollow axle that appears long enough for axle nuts. Would something like this be ok without a QR skewer (and simply using axle nuts), and on a fixed gear bike?

It's not a hollow axle hub per-se for quick releases...it's a drilled axle. A feature...

=8-)