On 2013-01-06, at 8:40 AM, David Dannenberg <ddannenberg@...
> This discussion echoes the discussion I have been having in my head and with some biking friends. I have 2.5" Hookworms on my Big Dummy.
> I have ridden several blocks on a completely flat tire. No fun, and slow, but marginally better than walking a full cargo bike
This Does Not Work with Big Apples. I tried once. The sidewalls are not stiff enough, and the tires fit loose (Schwalbe in general seem to be a little on the loose side, Nokian tends tight).
> That said, they are very heavy, and not particularly flat resistant. (I would rather not have to ride several blocks on a flat tire). I keep thinking I would like something lighter and more puncture proof in the same size and pressure range.
> Options? well, I looked at everything Schwalbe makes. The bigger sizes all run lower pressure. Also, the most puncture proof models like the Marathon Plus Tour with Smartguard are not made bigger than 2" (and are heavy).
I think you should look at the 2.35" Big Apples. 60psi is not much lower than 65psi. I don't get many flats; last one was something like a stiff piece of 10-gauge wire that went in through one sidewall and out the other.
> Meantime I have heard of studies that show that, contrary to intuition, tires at lower pressure under many circumstances are actually faster than tires under high pressure. This is especially true on gravel or uneven surfaces where apparently the compliance of a soft tire is preferable to the energy wasting bounce and ricochet of a hard tire. I ride a combination of dirt road and pavement and still lean toward the high PSI….but perhaps I am wrong in that. The soft is more comfortable, but feels slower.
I compared 700c x narrow x 120psi, versus 26"x2.35" Big Apple (60psi), and the Big Apple had lower resistance. However, when the pressure is significantly down (below 40psi) I notice that it appears to be slower. At intermediate pressures I am not sure, but the front end is more prone to shimmy if I ride no-hands.
What I have read in other places is that if equals are compared (meaning, equal sidewall tension, so 60psi in a 60mm tire, or 120psi in a 30mm tire, and tires otherwise the same) the fat tire will have lower rolling resistance. However, air resistance matters too, and the top edge of the tire front hits still air at double your road speed.