I run the Michelin Pro Race 2 Tires in 700x25C on our Co-Motion Robusta, the tire measures more like a 700x27C, the Michelin 700x25C tires run a little larger in size than what the sidewall states. Dewan the owner of Co-Motion recommended this tire to me for my needs and recommended 130 PSI even though the tire said max inflation of 106 PSI on the sidewall. I have had no problems what so ever. I ran 130 to 135 PSI in my 700x28C Conti Ultra Gater Skins (the sidwalls said 120PSI max) with no problems as well. With a tandem you have to run a little higher pressure in the tires to prevent pinch flats and for proper tire performance on a tandem. The smaller the tire size used such as a 700x23C or 700x25C a higher pressure is needed to prevent pinch flats and to improve tire performance in a tandem application.. Me and the wife weigh in at about a 340lb to 345lbs plus 30lbs for the tandem.

There is a great article on tires and tire inflation at Precision Tandems web site www.precisiontandems.com the article is on the left side of there main page. The article has a chart or graph specific to tandems tire size, team weight, and air pressure needed for tire size and total team weight. This chart is worth taking a look at. (the article is a good read)

Good luck,
Bill G