Hey all
I'm building a touring/commuting rig from an old mtb w/26 inch wheels. I'm curious as to what gear ratios or chainring/cassette combos people find best for city riding/light touring. Thanks!

City riding/light touring require two significantly different gearing.

My favorite gearing for the city is a 3spd hub setup with a range of ~45-80 gear inches.

Light touring requires a larger range and more gears.

too broad of a question I think. What's the likely terrain? I need a gear under 30 inches but I live in the mountains. Typical mountain bike gearing is pretty versatile so you could try that.

Thanks mike and daredevil. I've actually got a mtb crankset around - 44/32/20 with a 12-34 8 speed cassette. Since I ride around w/a range of 35-100 inches just using the smaller of my two front rings (52/46), I was just wondering if I would ever use the lower tooth rings on the mtb. Sounds like it'll probably be fitting, esp after packing some weight onto the bike.

have a look at Sheldon Brown's gear calculator: https://www.sheldonbrown.com/gears/ and compare some variations with your current set up(s).

I did this before rebuilding my touring bike from double to triple and ended up with 44/32/22, 11-28, so as not to have such big jumps and to cover the range I'd need for loaded touring. For a commuter/light touring I'd go for 48/36/26 with the same 11-28... but hey, that's just what suits me

I've got a 44-32-22 crankset with a 12-25 cassette on one of my commuters. The only time I ever use the 22T ring is climbing the 20% hill up to my house, and even that I can do with the 32T ring if I want to. I only use the 22T when I'm feeling lazy.

Get a closer ratio cassette to match the hardest climb and heaviest load you will carry - maybe 12-26, but you know how strong you are, and what climbs you will be facing. There is no shame in dismounting to take photos on the steep climbs while touring.

Well if you are in a relatively flat city, using the bike for commuting and light packing; I would go with a road bike gearing: triple crank set 50/39/30 for example with a cassette 12-27 and thin tires.
But if you are more into tough tourings, gravel and dirt roads plus supercharged panniers and bike, I would definitely select a mountain bike gearing: triple crank 48/38/28 for example with a cassette 11-34 and moderately thick tires.