Rivendell tire TPI?

All the talk about tires lately got me wondering about the threads per
inch in the casings of Rivendell tires.

Anyone know the TPI for the Roll-y Pol-y and/or Ruffy Tuffy?


Thanks,

Jim Rogers

In article ,
Jim Rogers wrote:
All the talk about tires lately got me wondering about the threads per
inch in the casings of Rivendell tires.

Anyone know the TPI for the Roll-y Pol-y and/or Ruffy Tuffy?

Why not ask Rivendell? They'll know.

These wonderful tires should not be judged by "normal" tpi numbers as they
use a kevlar wrapped thread in the casing. It's just Apples and Mangos.
Tom

--
Bruni Bicycles
"Where art meets science"
brunibicycles.com
410.426.3420
Paul Southworth wrote in message
...
In article ,
Jim Rogers wrote:
All the talk about tires lately got me wondering about the threads per
inch in the casings of Rivendell tires.

Anyone know the TPI for the Roll-y Pol-y and/or Ruffy Tuffy?

Why not ask Rivendell? They'll know.

Why not ask Rivendell? They'll know.

They're a small operation and I hate to tie up their staff for a
question to which someone here might know the answer. (Sure enough,
when I called to ask, the guy was away from the phone for awhile
getting the answer.)

The answer-- 127 TPI for both.


Another question-- anyone know if the "extra roundness" of their tires
is the real deal or just a marketing angle? Are they really any (or
much) rounder in cross-section than other tires? If so, does it really
make that much difference in their performance?

--Jim

Jim Rogers writes:

They're a small operation and I hate to tie up their staff for a
question to which someone here might know the answer. (Sure enough,
when I called to ask, the guy was away from the phone for awhile
getting the answer.)

The answer-- 127 TPI for both.

I doubt it after seeing the claims of other tire brands that bounce
all over the range and Continental's claims that are obviously not
threads per inch... but could be filaments in the threads, something
we haven't previously counted.

Another question-- anyone know if the "extra roundness" of their
tires is the real deal or just a marketing angle? Are they really
any (or much) rounder in cross-section than other tires? If so,
does it really make that much difference in their performance?

Please clarify. To what roundness does this refer? Tire
circumference or tire cross section and how do they claim they measure
this? A tire that is out of round goes lump-lump-lump ad you coast
down a smoothly paved road so that isn't a problem with any tires I
have ridden. Cross sectional roundness is a function of inflation.
An inflated tire has a round cross section unless it is a belted
radial tire as on cars.

Jobst Brandt

On Tue, 11 May 2004 18:33:06 GMT,
wrote:

Jim Rogers writes:


Another question-- anyone know if the "extra roundness" of their
tires is the real deal or just a marketing angle? Are they really
any (or much) rounder in cross-section than other tires? If so,
does it really make that much difference in their performance?

Please clarify. To what roundness does this refer? Tire
circumference or tire cross section and how do they claim they measure
this? A tire that is out of round goes lump-lump-lump ad you coast
down a smoothly paved road so that isn't a problem with any tires I
have ridden.

Not their claim.

Cross sectional roundness is a function of inflation.
An inflated tire has a round cross section unless it is a belted
radial tire as on cars.

Jobst Brandt


This is it...

http://rivendellbicycles.com/webalog...bes/10033.html

"3. It has a round cross section for good cornering. They are rounder
than any other tire, and as a result we haven't ridden a better
cornering tire. The extra degree of roundness comes from a three part
mold, instead of the usual two part mold, which most modern road tires
have...."

I had some WTB Slickasaurus tires- 26"x 1.5" - that had almost an
egg-shaped cross section. Round on the outer/tread side (although
maybe not 'rounder'? Cut about a third off of an egg from the
pointed end and what's left is the idea of the cross section.

Would tread design and application of the tread affect the cross
section of the tire? When you say all non-radial belted tires have a
round cross section, is this on the interior and can be changed on the
exterior through treading?

"Jim Rogers" wrote in message

Another question-- anyone know if the "extra roundness" of their tires
is the real deal or just a marketing angle? Are they really any (or
much) rounder in cross-section than other tires? If so, does it really
make that much difference in their performance?

My original Ruffy's are "rounder" and a bit bigger then the spanking new
Ruffy's I just received, one of which I just put on the front of my Heron.
It's seemingly taller as well, probaly a result of not as round and slightly
smaller (diameter).

The new one's measure slightly over 27mm though.

Steve B.

Dan Daniel writes:

Another question-- anyone know if the "extra roundness" of their
tires is the real deal or just a marketing angle? Are they really
any (or much) rounder in cross-section than other tires? If so,
does it really make that much difference in their performance?

Please clarify. To what roundness does this refer? Tire
circumference or tire cross section and how do they claim they
measure this? A tire that is out of round goes lump-lump-lump ad
you coast down a smoothly paved road so that isn't a problem with
any tires I have ridden.

Not their claim.

Cross sectional roundness is a function of inflation. An inflated
tire has a round cross section unless it is a belted radial tire as
on cars.

This is it...

http://rivendellbicycles.com/webalog...bes/10033.html

Wow what a bunch of double-talk. Of course a 700-28 is smaller than a
700-32 so what else is new. Besides:

:1. Sizewise, it's big (think "round and rolly") with larger air
: volume than most any tire near 700x28. It's smaller than the
: comfortable and fast 700x32 Avocet slick, and since the Avocet is
: too big for most modern short reach (compact) brake road frames,
: our Roll-y Pol-y couldn't be that big; and yet, with a name like
: Roll-y Pol-y, it is fatter and more round than any other tire
: close to its size. The designation on the sidewall is 700x28 due
: to some Japanese law we're told, but it measures a true 27mm wide
: on most road rims.

Either they are using the correct tire cross section size or they
aren't. Rolly poly or not it cannot have a larger air volume than any
other 28c tire unless the casing has zero thickness. Tread thickness
does not factor into the 28 of 28mm cross section, only the casing OD
when inflated and that is always round, as I explained above.

"3. It has a round cross section for good cornering. They are
rounder than any other tire, and as a result we haven't ridden a
better cornering tire. The extra degree of roundness comes from a
three part mold, instead of the usual two part mold, which most
modern road tires have..."

Oh hogwash! The roundness comes from basic physics of an inflated
inelastic thin walled tube. That is what a bicycle tire casing is and
all of them have a round cross section. Tread rubber can be formed to
other shapes as we see in knobby tires but the tire IS round in cross
section. There is no way they are more or less round.

On top of that, the part smooth and part cosmetically micro-ribbed
tread does nothing for traction and as the ad copy states, it tries to
satisfy those who want slicks and those who want patterned tread.
Well that tells me they don't know the difference.

I had some WTB Slickasaurus tires- 26"x 1.5" - that had almost an
egg-shaped cross section. Round on the outer/tread side (although
maybe not 'rounder'? Cut about a third off of an egg from the
pointed end and what's left is the idea of the cross section.

Your shape was in the tread, not the tire casing and the thinner the
tread the less that part of the tire will deviate from perfectly
round.

Would tread design and application of the tread affect the cross
section of the tire? When you say all non-radial belted tires have
a round cross section, is this on the interior and can be changed on
the exterior through treading?

The casing will be round. Obviously you can stick a number of odd
shapes on top of that but the only way it will remain round is with NO
tread rubber.

Jobst Brandt

On Wed, 12 May 2004 00:16:18 GMT,
wrote:



On top of that, the part smooth and part cosmetically micro-ribbed
tread does nothing for traction and as the ad copy states, it tries to
satisfy those who want slicks and those who want patterned tread.
Well that tells me they don't know the difference.


I actually think that this is a joke on their part. I don't know if
they have a strong opinion on file tread versus smooth, but the
alternating pattern is a silly thing that I believe they would laugh
at as quickly as you.

Every now and then the Rivendell people actually put their money where
their humor is, not just where their next mortgage payment is going to
come from Of course, personally, of all the places on a bike to be
making jokes, my contact patch with the road is not a source of humor
or silly fashion statements. To each their own....

Thanks for your other comments.

On 2004-05-12, wrote:
Dan Daniel writes:

Another question-- anyone know if the "extra roundness" of their
tires is the real deal or just a marketing angle? Are they really
any (or much) rounder in cross-section than other tires? If so,
does it really make that much difference in their performance?

Cross sectional roundness is a function of inflation. An inflated
tire has a round cross section unless it is a belted radial tire as
on cars.

"3. It has a round cross section for good cornering. They are
rounder than any other tire, and as a result we haven't ridden a
better cornering tire. The extra degree of roundness comes from a
three part mold, instead of the usual two part mold, which most
modern road tires have..."

Oh hogwash! The roundness comes from basic physics of an inflated
inelastic thin walled tube. That is what a bicycle tire casing is and
all of them have a round cross section. Tread rubber can be formed to
other shapes as we see in knobby tires but the tire IS round in cross
section. There is no way they are more or less round.

The casing may be round on all tires, but the tread rubber seems to
be frequently formed to less round shapes. What the Rivendell text
above seems to be saying, and what I have experienced by riding on
these tires, is that the Rolly Poly / Ruffy Tuffy tires have very
round profiled tread--a continuously smooth curve all the way around
the edge of the tire.

In actual riding, they are the best cornering tire I've ever ridden.
Without additional effort on my part, I find myself leaning over more
than I have on any other rubber. The tread is basically slick, with
only a hint of a pattern on it. They're easy rolling, easy mounting
and so far have shown good protection vs. sharp road hazards.

Jobst, no matter the description, in reality the Rivendell tires seem
to be very much in line with what I've read about your opinions on
proper bicycle tires. If you ever decide to try them, I think that
you will like them very much.

Regards,

Greg
--
Gregory S. Sutter "How do I read this file?"
"You uudecode it."
http://zer0.org/~gsutter/ "I I I decode it?"