(Wheels and) tires are to bicycles what speakers are to hi-fi

On Sat, 1 Aug 2009 13:22:25 -0700 (PDT), pm
wrote:

On Aug 1, 1:11*pm, Chalo wrote:
Michael Press wrote:

*PeteCresswell wrote:

OTOH, my car definitely runs better, handles better, and
accelerates faster after it's been washed. *Even more so after
being waxed.... -)

But I really do think there's something to the better rolling
perception.

I feel that too.

It's there, for sure. *I believe that it's as conspicuous as it is
because the gross amount of drag doesn't vary much with speed. *So
when you're just taxiing around, rolling resistance represents a large
percentage of total drag and it really comes through. *When you pick
up the pace and there are kgf of thrust at the rear tire to divvy up,
the dozens or hundreds of gf attributable to rolling resistance get
sort of lost in the noise. *But then when you're riding like hell with
some other folks to compete against, you get a keener sense of your
speed than when riding solo at the same effort, and that lets you
observe relatively small effects like rolling resistance.

Yep. When I first picked up an MTB I was impressed at how much faster
it was when I put slick tires on it. Now that I'm more fit and "ride
like hell" I am impressed by how my MTB with knobbies has basically
the same top speed as my touring bike with Paselas. The difference in
rolling resistance is easily felt when you coast to a stop though.

Carl could quantify that by seeing how fast a bike coasts to a stop
from 10 mph, or by going to his favorite analytic cycling calculator,
plugging in a ground slope of -1% and a rider power of 1 watt and
seeing the effect of rolling resistance in that situation.


I spend a lot of my time on the bike in the city just coasting down,
or idling while looking for an opening in traffic, or cruising
alongside my wife. *In these circumstances, efficient tires make the
difference between low effort and negligible effort at the pedals.
That's not important, really, but it is nice.

Chalo

Dear pm,

The original claim:

"Maybe its different with larger tires, but I feel a very large
diff in rolling resistance between a low thread count tire and a
high tread count tire."

Cheers,

Carl Fogel