All this stuff about tires is very interesting, because it was all well-understood by...about 1896.
Google book search, free read online, "Palmer Tire" and choose 19th century view.
Read about how perfect various bike tires were by...1898? Tubulars were -easy- to patch on the road, if merely punctured.
True then and now: the thinner the tread and the more supple the casing and the higher the pressure and the narrower the tire,
the easier the roll at high speed, but...thin, high-pressure tires give up much of the cushion effect.
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I love, will always love, the easy roll (excellent for 15mph biking on asphalt, for instance)
and the soft, lovely ride of a Bontrager Hank,
huge volume, slick tread, rolls by itself, nearly, very efficient for cruising bike speeds,
and laughs at ruts and bumps and sandy patches of asphalt are no slip-risk to a Hank and yourself.
Hank is perfectly slick, and so no tread noise at all, dual compound, (sticky on the sides)
and we don't need tread, as we all know, for a street tire, not even on wet roads.
There are very few balloon tires with true slick treads.
Hank is not puncture resistant or thorn resistant,
no more than a thin glove, but it is comfort defined, the best possible, nearly, for a fat, cushy tire,
Hank will take jumps and bumps without damage.
It is tough against impact, any impact on the street.
It comes in your choice of black wall, or black with a red stripe on the sidewall.
The Schwalbe "Kojak" is another candidate for any MTN biker
who wants to get a taste of what road bike slicks are like,
but wants to keep to relatively large volume tires for comfort too.
((I have not price-searched for best price))
http://www.amazon.com/Schwalbe-Kojak-Mountain-Bicycle-Tire/dp/B003ZJBQT2
Bontrager Hank is only available through your local Trek dealer or direct from Trek online.
http://bontrager.com/model/02856
(good picture above)
It's a beautiful tire, but it is also so relatively fat, that it may not fit in some skimpy front forks.
It is a handsome devil, though.
http://tinyurl.com/6chxlbu
(((so much for fat tires that roll sweet on cruiser and mountain bikes))
Schwalbe Kojak images for comparison,
http://tinyurl.com/6hk9ct4
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The narrow and hard-pumped tire is fastest and easiest to power.
The hard-tread, thick tire, not too highly-inflated, tends to be more resistant to punctures.
The wide or soft tire is softest to ride on and offers traction and footing unrivaled by others.
Tread is not needed or wanted for asphalt roads.