You can safely run that "85 psig" rated tire at close to 100 psig. The ratings are conservative, and have a large margin of safety, in my opinion. I ran my Electra Townie's tires 15 psig above rating at the recommendation of the LBS and had no problems. I run my Kona Dew Deluxe's 85 psig rated tires at 95 front and 100 rear with no problems (once I put in a good rim strip instead of the rubber "flat maker" that came in the rim). The higher pressure makes the tire MUCH faster, and seems to resist external puncture just as well or better as the sidewall pressure. Just my experiences...