Just had the LBS convert my wife's Schwinn Windwood cruiser

to a 3spd with a SA SRC3(II) hub built into the original wheel. I really thought I wanted a 22t cog instead of the 18t the hub came with. They built up the wheel and got it back to me in a day but, they didn't replace the 18t cog. The wrench said it would have to have a chain to accommodate the larger cog and we should try it with the 18t. It's ok but, I still want the 22t cog.

There is no way I could have built up the wheel. I think I can change the cog myself. I don't have a clue how to know what to look for in the way of a chain. Will it have some sort of master link? I have a chain tool if I need to push out/in a pin. Don't know how to size width or length of chain.

Suggestions?

You need a 1/8" chain. Any bike shop should be able to sell you what you need and answer any questions. The clip that holds the cog can be removed with a flat blade screwdriver and installed with fingers.

Many 1/8" chains are pressed together, not 'quick-linked'. But adding links to a chain is one of the easiest 'fixes' there is. All you have to do is make sure the chain is snug before you get to the back of the diagonal dropouts. In fact, one of the little tricks I use is to snug the wheel all the way back in those dropouts, and then size the chain like you would for a multi-speed -- wrap it around each gear, front and back, see where they come together, and remove one more link.

Would you suggest getting additional links and adding to the chain I have, rather than buying a new chain?

Sounds like he was just trying to make sure you did not preemptively spend money on something you may or may not have needed. I would think if you take it back to the shop and tell him you rode it and really would like the 22 he probably will do it for not much more than the cost of the parts. At least, that is how I would handle it as the wrench.

Got it. I'll talk to him and see what he says. Thanks for the replies!

Id go with new chain... 0ne thing to consider, the bigger rear cog may get a dragging on the under side of the chainguard.


Note:
One piece cranks do offer the possibility of putting a smaller chainring on them,
It's another way to lower the external gear ratio.

yes width 1/8" .. Chain length is easily determined on the bike , slip the rear axle forward , before you put it on,
so you have the adjustment range for tension, as it wears-in.