I run a set of the Michelin Country Rocks on my steel MTB. They measure out exactly to their nominal size (1.75" wide), and they're actually rather light for their size. Their casings are pretty supple, especially for the moderate price. Chain Reaction has them on sale for 20 bucks right now.

Michelin Country Rock MTB Tyre | Chain Reaction Cycles

I have used 1.4" tires on this same bike (Michelin City Proteks), and really don't prefer tires that narrow. I didn't sacrifice any speed by going to the wider 1.75" tire. In fact, due to the Proteks' thick puncture belt and small volume (requiring more air pressure), the bike was rather uncomfortable on those tires (the Country Rocks are actually lighter in weight). I run the Country Rocks at 40-50 psi and it's quite nice. Very smooth, very quick.