[MENTION=134410]rumrunn6[/MENTION] mentioned Protek tires -- I've ridden a set of 700x40 Michelin Protek Cross Max for almost two years and am still pleasantly surprised by how well they defy conventional wisdom about heavy, puncture resistant tires with stiff sidewalls.

To me, they feel harsh at the recommended 75 psi for my weight (160 lbs), and not any faster than at my preferred 50-60 psi. Occasionally I'll let them drop to 40 psi unless I'm hauling a heavy load of groceries or other stuff -- it's my errand bike. At around 50 psi they feel cushy but not sluggish. Better than two other sets of lighter weight but similar design chevron tread 700x38 tires (Specialized and Innova).

It's difficult to be sure what the tires are capable of since they're on a heavy upright comfort hybrid with suspension fork. I can cruise all day at 12 mph. I'd need to swap 'em over to my lighter, rigid fork/frame Univega to see how the Michelins would compare with the Conti Speed Rides on the Univega, which are less than half the weight of the Protek Cross Max.

In comparison, the same felt effort on the lighter weight Univega with lighter Conti tires usually cruises around 14 mph. Not a whole lot faster all things considered.

And the same approximate felt effort on my much lighter weight road bike (23-24 lbs) with skinny featherweight slicks (205 g each) is good for 16 mph. Seems like I should be a whole lot faster than on a 35 lb upright comfort hybrid with tires that weigh 1,100 g each. Can't be the engine. I'm blaming the tires.