Re: Patching TPU innertube

cyclintom <cyclintom@yahoo.com> wrote:

On Fri Dec 27 08:54:06 2024 Roger Merriman  wrote:

Frank Krygowski <frkrygow@sbcglobal.net> 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.
 

 
The difference I was talking about was feel, than any speed/rolling
resistance gains which apparently one does also gain.
 
Don?t know if you can tell feel with ultralight butyl tubes, or latex as I
never explored those.
 
<https://www.bicyclerollingresistance.com/specials/tpu-inner-tubes> they
tested most TPU tubes plus some latex and lightweight butyl ones.
 
Clearly is a drum than real world, though does show that for all its
fragility and lack of air keeping latex rolls like no other, though TPU
isn?t far behind it.
 
TPU can be very light but at those weights will like latex leak air, aka
will need pumping after each ride.
 
Unlike butyl or even tubeless which will loose air over time but certainly
don?t need to pump back up before each ride etc.
 
Roger Merriman

 
 
 
 
Think about it Roger, You kind of MTB tires are maybe 15 watts of rolling
resistance. Inserting latex tubes decreases the rolling resistance maybe
5% and TPU is less than improvement than that.
 

Yes Latex narrowly comes out faster than TPU which is faster than
lightweight butyl tubes. Though if rolling resistance was your aim, then
tubeless is I believe slightly lower again.

Trying to maintain 15 mph into a 5 mph headwind is probably 200 watts of
aerodynamic drag on a road bike and almost double that on an upright position on an MTB.
 
Do you trhink that you're going to evrn feel a 5% reduction in rolling
resistance even if you can feel a softer ride on your knobbies?
 

I wasn’t talking about rolling resistance, Frank introduced that! But ride
feel which certainly on the Gravel bike is noticeable even at same
pressures, with tubeless can reduce down as no tube to pinch. So can reduce
the pressures a touch more.

The question I had been pondering was would a MTB tire exhibit the same
effect as gravel tires ie feel more plush with TPU or tubeless, I’m sure
that XC tires would as they are light and supple tires, trail and enduro
types let alone DH I’m unconvinced one would as the sidewalls are armoured
and thus quite a bit stiffer.

Roger Merriman