On Nov 3, 11:32*am, wrote:
I didn't see a cross section on that web site. *Can you direct me to
one?

Here's the only picture I've found of the Challenge "Open tubular"
ti

http://tinyurl.com/562n9m

Here's my favorite description of these tires (marketing, ya gotta luv
it!)

"The Challenge Criterium Nerone Clincher is a handmade open tubular
that rides… like a tubular. Like a Clement tubular. Clement tubulars.
Those two words used to leave racers speechless. The Criterium Seta
was considered by many the acme of quality, the tires you saved for
race days, the tires that were stored covered and airless for hopes of
extending their useful life, the tires you lovingly washed after each
race, air dried, and then packed away again.

Clement was bought by Pirelli and they moved everything to Thailand.
Rubber comes from Thailand, so they, and many tire makers, figured
they'd save money by making tires near the source. And, like many
conglomerates, Pirelli realized that the bike world is not a huge
business. They folded the Clement operation.

Like a phoenix, Challenge tires rose from the ashes of those Thai
facilities. Between the Italian distributor and the Thai
manufacturers, they resurrected the tires. Like the good old days, the
tires are still handmade. Also, like the good old days, the legendary
tread is still glued by hand to the casing after the casing has been
tensioned. Many believe that a tread made separate from casing rides
better and with less rolling resistance because it doesn't get
deformed by the inflation of the tire.

The Criterium Nerone Clincher utilizes the same tread as both the
legendary and contemporary Criterium Seta. Longitudinal ribs down the
center, with herringbone on either side. In keeping up with the times,
Challenge offers the tires both as tubulars and open tubulars. "Open"
meaning the casing isn't stitched to itself like a sew-up, i.e. an
open tubular is a clincher. Challenge has also eschewed the cotton
casing for polyester. The casing is still corespun, resulting in a
thin, light, flexible case that is super-supple. The thread count is
300 threads per inch (TPI), which in cycling circles is considered a
fine casing. Also keeping up with the times, the sidewalls are colored
black (Nerone) instead of the traditional tan (or "natural").

To give the tire better flat protection, a thin 300TPI corespun
polyester belt, the same material that makes the casing, is glued
above the casing and below the tread. It is also glued on when the
casing is under pressure. They call this their Puncture Protection
System (PPS), giving a little more protection under the tread while
leaving the sidewalls thin and supple.

The Challenge Criterium Nerone Clincher is an open tubular design. The
tire measures 700 x 23mm wide. It has Challenge's Puncture Protection
System (PPS). The casing is corespun polyester. The beads are made
from Kevlar. The tire casing has 300 threads per inch (TPI). The tire
has a Black tread and Black casing. The weight is 210g."

Come on, all-black, 300 tpi, 210g, and a Puncture Protection System
(PPS), what's not to like?