Tire pressures embossed on the tire sidewall often have little or no relation to the proper tire inflation pressure. Check on the actual tire manufacturer's website to determine the actual inflation range for a particular tire. Running less pressure than recommended can result in greater chance of puncture, either from road debris (glass, thorns, etc.), or from pinch flats due to running over things like curbs or manhole covers, and bike handling issues. Running a tire at less than the manufacturer's recommended pressure might be more comfortable, but can result in safety issues and increased risk of punctures. Narrower tires require greater minimum pressures within a narrower range, wider tires less so within a wider range, but consult the tire manufacturer to be sure the range for your specific tire. I run 700Cx23mm Conti Gatorskin tires on my road bike, and their recommended pressure is 110 to 120 psi — a very narrow range.