Hi
I am thinking of swapping out a hub and wonder if there is a description or definition of the specs used to describe the hub for confirming compatability?

thanks
frogeye

Over Locknut Distance (OLD) is 130mm for road, 135 for hybrid/MTB, ie the space between the rear dropouts.
That is about the only hub compatibility issue with the frame.
You need the same spoke count as your rim.
The hub inter-flange distance is just a wheel builder's issue.

Are you going to change just the hub in an existing wheel while keeping the spokes and rim or are you changing the entire wheel? Front or rear wheel? The info you need is quite different for each case

well actually what to do is kind of the question. it is a rear wheel in question and my assumption in asking is to keep the rim and spokes and change the hub. the reason for the question is that i heard a periodic sound from the rear and wondered if it was a bearing, although that isnt positive. the hub is a shimano fh 2200 via. is is possible that it just needs grease? I had assumed it was permanently lubed but i don't know that, i guess.

more generally if i want to go for relatively long tours, what is the life expectancy for a hub? it has a few miles on it and it is possible that replacement would be better an trouble on the road, although i like making old things work philosophically...

Shimano hubs are "cup and cone" types and are not permanantly lubed. They need periodic maintenance and how often depends on the miles and conditions you ride. It's fairly simple requiring only a cone wrench and fresh grease. The tutorial on Park Tools web site will show you how to do it.

thanks hillrider park is very useful info, but i have a question.
what i see there seems to be the description of an overhaul, yet you mentioned needing only a cone wrench. Am i looking at the wrong page? do you have to remove the cassette and hub, or can you just slip the axle out and pack some grease in?
this is the page i am looking at for reference: https://www.parktool.com/blog/repair-...reehub-service

thanks for your comments and advice!
frogeye

https://www.parktool.com/blog/repair-...and-adjustment

expecting Permanently , lubed ..

A cone wrench is the only "bike specific" tool you need. The locknut is removed with a common 17 mm openend or box wrench and you don't have to remove the cassette to remove the axle. Loosen the locknut on the non-drive side (opposite the cassette), remove it, any spacers and the cone and pull the axle out of the cassette end. Clean both sides, pack the races with grease and bearing balls (new ones are nice) , and reassemble.

If you want to remove the cassette you will need a specific lockring tool and a chain whip. To remove the freehub body from the hub, you will need a 10 mm allen key.

cool thanks