OK to begin with sorry but I am new to the bike touring world and I am trying to figure out tires. My bike came stock with 700x48c tires on Alex D17 wheels(rims). What is smallest width tire that will work. The reason I am asking is I would like to replace them eventually with a set of Schwable touring tires. Thanks for any help.

how wide are your rims? I've never heard of 48c tires before (not to say that they dont exist) are you sure it isnt 38?

Knowing the width of the rims would be helpful, but from my own experience, i'd guess you'd be OK down to 32 or so with any rim I've seen. Before I settled on 700x35s for nearly all my riding (I weigh 240; got no use for skinny tires), I swapped randomly from 23mm through 41mm on several sets of wheels with no problems.
Re 48mm tires: I've seen them a few times, and they're generally heavy, thick rubber. I think you'd notice a much different feel with a lighter, "roadier" 35 or 32, like a Panaracer Pasela.

I found the Alesx TD17 rims at Universal Cycles and it appears that inside width is in the 17mm range so far as I can tell. Unfortunately most rim makers list the outside width while per ISO the inside width determines tire width compatibility.

Based on the latest ISO recommendations your rims should be good for tires from about 25mm width minimum to 50mm per the below link.

https://www.schwalbetires.com/tech_in...dimensions#rim

Thanks for the link. Thats what I was looking for, and yes the inside spacing is 17mm.