Originally Posted by
DubT
I do not understand the trend to bigger and bigger tires. I still run 700 X 25's and sometimes run a 700 X 23 on the front of our Calfee and our ride is completely comfortable. I run 100 psi in the front and 105 in the rear with no problems with pinch flats. I do announce bumps to my stoker so she can be prepared for bumps. We ride typical county/township roads in central Illinois and do not see any need to go with bigger fatter tires. Maybe it is the carbon fiber as Zona mentioned.
Aluminum tandem bikes (& half bikes for that matter) really benefit from plumper tires. Our Santana Scandium only wears 700 x 32c Vittoria's (hypertour). 85-90 psi is all they need to be inflated to. The ride is so much nicer than any high dollar 28mm tire I've tried over the years. And we are able to ride faster with them, too (as waynesulak's comments attest). Another benefit specific to the Santana is the "pneumatic trail" effect. The twitchy, floppy steering typical of Santanas is lessened noticeably. If I weren't running rim brakes I would size down to 650b, too.
Our Paketa sports 700 x 23c yet rides smoother than the Santana on most roads. So, frame material really makes a huge difference.
The average road surface quality in San Diego county goes from poor to post-apocalyptic, with new pavement only just starting to show up in the last year. My aluminum framed "toss in the car" road bike rides best on 700 x 28c with clearance for the fatter stuff. I fear that if I were to put bigger tires on, I won't want to go back - don't want the conundrum of climbing weight vs. comfort. I only ride half bikes for 2-3 hours a week at most as opposed to 5-10 on the tandems.