Re: Patching TPU innertube

On Sat, 04 Jan 2025 22:54:20 GMT, cyclintom <cyclintom@yahoo.com>
wrote:

On Mon Dec 30 23:07:58 2024 Frank Krygowski  wrote:

On 12/29/2024 11:38 AM, cyclintom wrote:

On Sat Dec 28 18:25:31 2024 Frank Krygowski  wrote:

On 12/28/2024 12:32 PM, cyclintom wrote:

On Thu Dec 26 22:10:15 2024 Frank Krygowski  wrote:

On 12/26/2024 5:32 PM, Roger Merriman wrote:

>
The issue for me is that while Gravel tires absolutely do feel more supple
with TPU tubes, these are tires while some claimed sidewall protection,
these aren?t like Trail etc MTB tires which have reinforced noticeable
stiff sidewalls is aren?t floppy, each tire is 1kg or so.
>
Hence I wonder if a upgrade to TPU tubes would be noticeable...

>
>
I'd be interested in people's personal measurements of differences. If
someone here had access to some long, gentle downhill and kept track of
terminal coasting speed using different tires, different tubes, but
otherwise identical equipment, terminal coasting speeds might be good
information.
>
It would be best to test in consistent temperatures and with negligible
wind, of course.

>
Frank, what do you believe the difference in terminal velocity would be with 1/2% decrease in rolling resistance on a 5% slope which is almost entirely set by the tires? For crying out loud, you claim to be a mechanical engineer! Aerodynamic drag would be 100 times the rolling resistance.

>
I'm breaking my recent resolution to skip responding to you, Tom. It's
normally a futile endeavor.
>
But as to your question: Aerodynamics was the specific reason I
specified a _gentle_ downhill. I think the best might be one that would
give a terminal speed of 12 to 15 mph, since at those speeds aero drag
is at least roughly the same magnitude as rolling resistance.
>
And yes, I expect the differences would be difficult to detect. Which
raises the question: If the differences are difficult to detect, are
they really worth worrying about? Are they really worth the expense, and
the hassle of changing one's equipment?
>
If you're racing, perhaps so. Otherwise, it seems not.
>
If you get to your coffee shop fifteen seconds earlier, do they give you
a prize?   ;-)

 
 
 
 
What is a "gentle" downgrade? are you unaware that a bucycle will accelerate to the speed at which opposing forces equal the accelerating forces? Rolling resistance of tires is almost always a tiny component of this calculation. Jobst would have taken you apart for that comment.

 
Jobst would have understood it.

>
>
>
>
Why would you say something like that when I knew Jobst

 and rode with him and you didn't? Do you always pretend to know
people you've never met because you think it might impress others? In
those days we ran 53/42 and 14/21. A mild downgrade was anything you
could pedal down in high gear. You don't have a passing guess how fast
that was.



Yup, Jobst certainly knew you:

obst....@stanfordalumni.org
unread,
Dec 27, 2005, 12:32:04?PM
to A shy person writes:

By now we expect everyone to notice the anonymous postings from
Tom Kunich. His address is in SAN LEANDRO CA 94578 , and he lives
with his mother and he is not the owner of the he lives in.

Oh, you mean this guy:

Thomas H Kunich, Born: Oct 1944

{snip disclosed personal information}

aka. public information.

OH? This information is readily available from the web requiring no
special powers or authority. Just type the name and that's what you
get. I listed no more than what is open to anyone with WWW access.
It's quicker than a telephone book.

I thought we had gotten over him, now that we have other
contributors who are equally rude and obnoxious, always carping
while offering no useful information. A few names come to mind.

--
Cheers,

John B.