How to recognise a 6-speed freewheel compatible hub? I need to change the freewheel and the hub on my road bike and have been looking for a suitable replacement. I wish to keep my rim so I will rebuild the wheel. Also, I want to stay with a 6 speed cassette due to the limits of my current derailleur.

It seems easy to find a 14-28 6-speed freewheel. However, I haven't been able to find a 6-speed freewheel compatible hub, or at least one that states explicitly such compatibility.

My question is:

How do I know that a hub is 6-speed freewheel compatible? What measures do I need to look for to make sure that the cassette will match the length of the hub?

Here's an example of a frewheel that I'd like to match with a new hub http://www.ebay.co.uk/itm/SHIMANO-6-or-7-SPEED-FREEWHEEL-14-28-TEETH-SCREW-ON-NOT-CASSETTE-REAR-WHEEL-/121300234787?pt=UK_sportsleisure_cycling_bikeparts_SR&amp;var=&amp;hash=item1c3e0eb223.
All freewheel hubs have the same thread and are compatible with single, 5, 6, 7 and maybe some 8 speed freewheels. Position of the hub is set by dishing of the wheel and spacers on the axle. It's an interesting question. But I think that you should worry more about the rear spacing. 6 speed modern freewheel is not considered to be wide comparing to ones with more cogs. I wouldn't worry about this, just in case stay away from track hubs which are designed for single speed freewheels. I'm upgrading a 1980's ten speed bike now by replacing old 5 speed freewheel with 7 speeds to match new indexed 7 speed shifter. Previously I put 8 speed freewheel on that wheel but I had to add spacers to spread the seat stays a bit. It worked with original friction shifter but I don't like it.