[Yak] is it the tires?

[DAN Scott]

I have been riding a Bike Friday Pocket Companion (the stock model)  
for about 9 months. I've got about 1300 miles on it. I have noticed  
that friends on standard bikes with 700 wheels "outroll" me on almost  
any downhill. My BF is equipped with fairly basic stuff, including  
1.75  tires on 406 rims. These are Kendas, with a max inflation of 65  
pounds.

Today I rode a Trek 520, which a friend loaned me. It sure seemed to  
roll easier, whether uphill or down,  although when I looked, my  
speeds weren't much different from the BF. The Trek has 700 x 28  
Continentals, inflated to about 100 pounds.

Is it the tires? Or will a larger wheeled bike always seem to roll  
"easier"? Those of you who have Fridays with 406 rims, and also larger- 
wheeled bikes, how do yours compare?

Dan