Rolling Resistance

newsboy said:

Richard Cunningham, the editor of Mountain Bike Action, makes the
following statement in a bike test."Converting the tires to tubless,
would greatly improve the Santa Cruz's rolling resistance and boost
it's climbing potential as well"
Assuming equal tires, tread paterns,and inflation pressure, is this a
true statement. If it is true, by what mechanism is performance
increased?

Ask him...I'd be interested in the 'logic' he used. I think he needs to
talk to tire makrs for the reason tubeless is a good idea on MTBs...

In article <[email hidden]>,

newsboy said:

Richard Cunningham, the editor of Mountain Bike Action, makes the
following statement in a bike test."Converting the tires to tubless,
would greatly improve the Santa Cruz's rolling resistance and boost
it's climbing potential as well" Assuming equal tires, tread
paterns,and inflation pressure, is this a true statement. If it is
true, by what mechanism is performance increased?

How does rolling resistance happen in the first place? It happens from
the deformation of the tire against the ground as it rolls which causes
both flexing and stretching. This includes the rubber of the tread, the
fabric casing, and the inner tube. If you remove the inner tube *and*
all other things are equal, you will reduce rolling resistance.
However, tubeless tires are constructed somewhat differently to make
them air tight. My hunch is that it's a wash in terms of rolling
resistance.

newsboy said:

Richard Cunningham, the editor of Mountain Bike Action, makes the
following statement in a bike test."Converting the tires to tubless,
would greatly improve the Santa Cruz's rolling resistance and boost
it's climbing potential as well"
Assuming equal tires, tread paterns,and inflation pressure, is this a
true statement. If it is true, by what mechanism is performance
increased?

Dear Newsboy,

Leave out "greatly" and it's a reasonable claim.

Basically, the weight of the tire is a good indicator of its rolling
resistance--the more material squashed out of shape, the greater the
frictional losses.

The tube is flattened so hard against the inside of the tire that it
effectively becomes part of the tire--more material.

Lose the tube, and you lose some material. Less material, less rolling
resistance.

Getting a tire to seal doesn't take nearly as much material as a whole
tube.

But it's unlikely that any rider could tell the difference in climbing
on a real trail. The slight improvement in lowered rolling resistance
would probably be swamped by hitting a few extra roots.

What's the effect of lowering RR 10%?

This calculator suggests that narrow road tires have a typical RR of
0.0060, while typical 1.75" MTB have an RR of 0.0070:

http://www.kreuzotter.de/english/espeed.htm

This calculator lets you set the RR as you please (and assumes 0.0050
for RR--assumptions about averages vary):

http://w3.iac.net/~curta/bp/velocityN/velocity.html

I get 37.18 kmh with the defaults and 0.0050 RR.

Change the RR to 0.0070 for a MTB tire, and the speed is 36.29 kmh.

Drop that 10% to 0.0063 for an impressive reduction in rolling
resistance due to going tubeless, and the speed is 36.60 kmh.

Looks like 0.31 kmh, or 0.19 mph.

And that's for a rider putting out 300 watts. Riders putting out less
power will see smaller improvements for reducing their RR 10%.

Cheers,

Carl Fogel

Quoted message said:

newsboy said:

Richard Cunningham, the editor of Mountain Bike Action, makes the
following statement in a bike test."Converting the tires to tubless,
would greatly improve the Santa Cruz's rolling resistance and boost
it's climbing potential as well"
Assuming equal tires, tread paterns,and inflation pressure, is this a
true statement. If it is true, by what mechanism is performance
increased?

Dear Newsboy,

Leave out "greatly" and it's a reasonable claim.

Basically, the weight of the tire is a good indicator of its rolling
resistance--the more material squashed out of shape, the greater the
frictional losses.

The tube is flattened so hard against the inside of the tire that it
effectively becomes part of the tire--more material.

Lose the tube, and you lose some material. Less material, less rolling
resistance.

What makes you think a UST tire weighs less than a conventional tire plus tube?

Quoted message said:

Getting a tire to seal doesn't take nearly as much material as a whole
tube.

But it's unlikely that any rider could tell the difference in climbing
on a real trail. The slight improvement in lowered rolling resistance
would probably be swamped by hitting a few extra roots.

If there's any advantage at all, it is in being able to run lower air pressure
and get better compliance over those roots.

The calculation for that's a little more complex.

Ron

Quoted message said:

What's the effect of lowering RR 10%?

This calculator suggests that narrow road tires have a typical RR of
0.0060, while typical 1.75" MTB have an RR of 0.0070:

http://www.kreuzotter.de/english/espeed.htm

This calculator lets you set the RR as you please (and assumes 0.0050
for RR--assumptions about averages vary):

http://w3.iac.net/~curta/bp/velocityN/velocity.html

I get 37.18 kmh with the defaults and 0.0050 RR.

Change the RR to 0.0070 for a MTB tire, and the speed is 36.29 kmh.

Drop that 10% to 0.0063 for an impressive reduction in rolling
resistance due to going tubeless, and the speed is 36.60 kmh.

Looks like 0.31 kmh, or 0.19 mph.

And that's for a rider putting out 300 watts. Riders putting out less
power will see smaller improvements for reducing their RR 10%.

Cheers,

Carl Fogel

RonSonic said:

Quoted message said:

newsboy said:

Richard Cunningham, the editor of Mountain Bike Action, makes the
following statement in a bike test."Converting the tires to tubless,
would greatly improve the Santa Cruz's rolling resistance and boost
it's climbing potential as well"
Assuming equal tires, tread paterns,and inflation pressure, is this a
true statement. If it is true, by what mechanism is performance
increased?

Dear Newsboy,

Leave out "greatly" and it's a reasonable claim.

Basically, the weight of the tire is a good indicator of its rolling
resistance--the more material squashed out of shape, the greater the
frictional losses.

The tube is flattened so hard against the inside of the tire that it
effectively becomes part of the tire--more material.

Lose the tube, and you lose some material. Less material, less rolling
resistance.

What makes you think a UST tire weighs less than a conventional tire plus tube?

[snip]

Dear Ron,

Ignorance, as Johnson said, pure ignorance.

You're not only right, you're righter than your comment seems to
indicate.

The closest that I could find to the same model with the specs and the
same tread in both tube and tubeless was the IRC Mibro at Peformance:

Tubeless:
Weight: 770g
Size(S): 26 x 2.25
TPI: 66
Bead: Kevlar - Folding
Max PSI: 50
http://www.performancebike.com/shop/profile.cfm?SKU=20046&subcategory_ID=5430

Tube:
Bead: Kevlar - Folding
Max PSI: 50
Weight: 590g
Size(S): 26 x 2.25
TPI: 66
http://www.performancebike.com/shop/profile.cfm?SKU=20047&subcategory_ID=5430

The tread patterns look identical (some other tube/tubeless pairs that
I compared had similar model names, but very different tread).

Same max psi, same width, same tpi, same kevlar, same model, same
tread . . .

But the tubeless model weighs 180 grams more than the tube model!

Performance sells house-brand 26x2.1 tubes that weigh 200, 130, and 99
grams, including the valves.

I'm baffled--a tube and tire weigh less than a tubeless tire of the
same model in the bicycle world.

It's as if they added a whole tube to the inside of the tubeless tire
(even though the rim-side section isn't needed) and then added even
more.

Now someone has to explain this for me. Either I picked a very weird
model as an example (possible), or something weird is going on.
Someone must know the details and be willing to explain them to show
how mistaken I was.

If the tubeless tire does weigh more than the tube and tire of the
same construction (iffy--maybe construction is the key difference?),
then the tubeless tire should have worse rolling resistance.

Cheers,

Carl Fogel

Quoted message said:

I'm baffled--a tube and tire weigh less than a tubeless tire of the
same model in the bicycle world.

Carl, what are we gonna do with you? You are well-read, but you gotta
pick up a couple books on marketing.

It doesn't matter what something actually WEIGHS - it only matters
that it's perceived as "lighter"... facts seldom enter into these
decisions (and seemingly are becoming less and less important in
general).

It's like 1-1/8" headsets and stems and forks (which all weigh more
than their perfectly fine 1" brethren), yet the "perception" was that
they allowed the use of some different kind of magic technology that
made 'em lighter - so they sell like hotcakes, even to the
weight-weenie crowd (go figure).

Or how about some of the pedal systems that are actually a few grams
lighter than the typical Look pedals? Of course, the cleats weigh
five times as much as the Look cleats, making the combination much
heavier... but they sell like hotcakes to weight weenies too (at least
they can lift the bike to admire it without the "cleat penalty"😉.

Or maybe adding "lightweight carbon fiber rear ends" to titanium
frames? Just keep 'em away from a scale if you've already bought one.
But perception rules again.

So you get the customer to focus on the fact there's "no tube", put
the real weight in small print or express it in a fraction of a stone
or some other obscure method, or use vague language (... new
ubertubeless wondertire that's 38.77% lighter than the average tires
on bikes in India...).

Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $795 ti frame

On Thu, 03 Aug 2006 21:45:03 -0700, Mark Hickey <[email hidden]>

Quoted message said:

Quoted message said:

I'm baffled--a tube and tire weigh less than a tubeless tire of the
same model in the bicycle world.

Carl, what are we gonna do with you? You are well-read, but you gotta
pick up a couple books on marketing.

It doesn't matter what something actually WEIGHS - it only matters
that it's perceived as "lighter"... facts seldom enter into these
decisions (and seemingly are becoming less and less important in
general).

It's like 1-1/8" headsets and stems and forks (which all weigh more
than their perfectly fine 1" brethren), yet the "perception" was that
they allowed the use of some different kind of magic technology that
made 'em lighter - so they sell like hotcakes, even to the
weight-weenie crowd (go figure).

Or how about some of the pedal systems that are actually a few grams
lighter than the typical Look pedals? Of course, the cleats weigh
five times as much as the Look cleats, making the combination much
heavier... but they sell like hotcakes to weight weenies too (at least
they can lift the bike to admire it without the "cleat penalty"😉.

Or maybe adding "lightweight carbon fiber rear ends" to titanium
frames? Just keep 'em away from a scale if you've already bought one.
But perception rules again.

So you get the customer to focus on the fact there's "no tube", put
the real weight in small print or express it in a fraction of a stone
or some other obscure method, or use vague language (... new
ubertubeless wondertire that's 38.77% lighter than the average tires
on bikes in India...).

Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $795 ti frame

Dear Mark,

Er, yes, but why does a tubeless tire apparently weigh more than the
same model with a tube?

A quick look at Performance shows heavily treaded tubeless 26x2 MTB
tires at ponderous weights . . .
750g
790g
780g
700g
750g
700g

Not one under 700 grams.

The heavily treaded tube-using 26x2 tires seem to be bulemic . . .
565g
560g
560g
550g
620g (husky)
520g
570g
820g (wire-bead pig!)
580g (also wire-bead, but obviously eats no candy)
695g (how embarrassing)
495g (see what a 1.9 inch waist will do for you?)
500g (smaller knobs help, too)
810g (hulking 2.3-inch big-knob porker)
480g (very sparse knobs)
465g (full 2.1 inch, big, close-set knobs--oddly light)
680g
780g (2.5-inch mammoth)
345g Kenda Klimax "world's lightest mountain tire" 1.95 wide

Looks like around 600 grams.

Again, the apparently identical IRC Mibro tubeless and tube at
Performance, same width, kevlar, tpi, psi, and tread pattern:

Tubeless:
Weight: 770g
Size(S): 26 x 2.25
TPI: 66
Bead: Kevlar - Folding
Max PSI: 50
http://www.performancebike.com/shop/profile.cfm?SKU=20046&subcategory_ID=5430

Tube:
Bead: Kevlar - Folding
Max PSI: 50
Weight: 590g
Size(S): 26 x 2.25
TPI: 66
http://www.performancebike.com/shop/profile.cfm?SKU=20047&subcategory_ID=5430

What are the tubeless tires eating that makes their butts look so big?

Cheers,

Carl Fogel

Quoted message said:

RonSonic said:

Quoted message said:

On 3 Aug 2006 08:23:41 -0700, "newsboy" <[email hidden]> wrote:

>Richard Cunningham, the editor of Mountain Bike Action, makes the
>following statement in a bike test."Converting the tires to tubless,
>would greatly improve the Santa Cruz's rolling resistance and boost
>it's climbing potential as well"
>Assuming equal tires, tread paterns,and inflation pressure, is this a
>true statement. If it is true, by what mechanism is performance
>increased?

Dear Newsboy,

Leave out "greatly" and it's a reasonable claim.

Basically, the weight of the tire is a good indicator of its rolling
resistance--the more material squashed out of shape, the greater the
frictional losses.

The tube is flattened so hard against the inside of the tire that it
effectively becomes part of the tire--more material.

Lose the tube, and you lose some material. Less material, less rolling
resistance.

What makes you think a UST tire weighs less than a conventional tire plus tube?

[snip]

Dear Ron,

Ignorance, as Johnson said, pure ignorance.

You're not only right, you're righter than your comment seems to
indicate.

The closest that I could find to the same model with the specs and the
same tread in both tube and tubeless was the IRC Mibro at Peformance:

Tubeless:
Weight: 770g
Size(S): 26 x 2.25
TPI: 66
Bead: Kevlar - Folding
Max PSI: 50
http://www.performancebike.com/shop/profile.cfm?SKU=20046&subcategory_ID=5430

Tube:
Bead: Kevlar - Folding
Max PSI: 50
Weight: 590g
Size(S): 26 x 2.25
TPI: 66
http://www.performancebike.com/shop/profile.cfm?SKU=20047&subcategory_ID=5430

The tread patterns look identical (some other tube/tubeless pairs that
I compared had similar model names, but very different tread).

Same max psi, same width, same tpi, same kevlar, same model, same
tread . . .

But the tubeless model weighs 180 grams more than the tube model!

Performance sells house-brand 26x2.1 tubes that weigh 200, 130, and 99
grams, including the valves.

I'm baffled--a tube and tire weigh less than a tubeless tire of the
same model in the bicycle world.

It's as if they added a whole tube to the inside of the tubeless tire
(even though the rim-side section isn't needed) and then added even
more.

Now someone has to explain this for me. Either I picked a very weird
model as an example (possible), or something weird is going on.
Someone must know the details and be willing to explain them to show
how mistaken I was.

If the tubeless tire does weigh more than the tube and tire of the
same construction (iffy--maybe construction is the key difference?),
then the tubeless tire should have worse rolling resistance.

Cheers,

Carl Fogel

Ok then, we all agree the original statement by Mtn Bike Distraction is
BS....gee, what a shock!!

Quoted message said:

Er, yes, but why does a tubeless tire apparently weigh more than the
same model with a tube?

<snip volumes of data>

Quoted message said:

What are the tubeless tires eating that makes their butts look so big?

Good question - tire technology is close to horse racing in my
interest list (near the bottom).

My guess?

1) It takes as much or nearly as much extra material to make the tire
air-tight as it would take to build a tube.

2) Manufacturers realize that if riders realize that if it's more
hassle to change a flat on a tubeless tire, they've got to make sure
they don't have many flats - and add tread depth and/or kevlar layers
to prevent flats.

One could ask an even more appropriate question - "why even HAVE
tubeless tires in the first place". As near as I can tell, the answer
is the same as for many other "advancements" in the bike business...

Because we had a solution in search of a problem that doesn't exist.

Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $795 ti frame

Quoted message said:

RonSonic said:

Quoted message said:

On 3 Aug 2006 08:23:41 -0700, "newsboy" <[email hidden]> wrote:

>Richard Cunningham, the editor of Mountain Bike Action, makes the
>following statement in a bike test."Converting the tires to tubless,
>would greatly improve the Santa Cruz's rolling resistance and boost
>it's climbing potential as well"
>Assuming equal tires, tread paterns,and inflation pressure, is this a
>true statement. If it is true, by what mechanism is performance
>increased?

Dear Newsboy,

Leave out "greatly" and it's a reasonable claim.

Basically, the weight of the tire is a good indicator of its rolling
resistance--the more material squashed out of shape, the greater the
frictional losses.

The tube is flattened so hard against the inside of the tire that it
effectively becomes part of the tire--more material.

Lose the tube, and you lose some material. Less material, less rolling
resistance.

What makes you think a UST tire weighs less than a conventional tire plus tube?

[snip]

Dear Ron,

Ignorance, as Johnson said, pure ignorance.

You're not only right, you're righter than your comment seems to
indicate.

The closest that I could find to the same model with the specs and the
same tread in both tube and tubeless was the IRC Mibro at Peformance:
The tread patterns look identical (some other tube/tubeless pairs that
I compared had similar model names, but very different tread).

snipped refs

Quoted message said:

Same max psi, same width, same tpi, same kevlar, same model, same
tread . . .

But the tubeless model weighs 180 grams more than the tube model!

Performance sells house-brand 26x2.1 tubes that weigh 200, 130, and 99
grams, including the valves.

I'm baffled--a tube and tire weigh less than a tubeless tire of the
same model in the bicycle world.

This is not some unique or uncharacteristic specimen. It's like that pretty much
across the board.

Quoted message said:

It's as if they added a whole tube to the inside of the tubeless tire
(even though the rim-side section isn't needed) and then added even
more.

It isn't only the tire side, but there is a required rim strip to seal the spoke
holes and in the case of a conversion like stan's to wrap around the rim and
seal the bead. Don't neglect the slime-like sealant that is generally required.

But, yes there's almost an entire inner tube's worth of additional rubber on the
tire carcass itself. That will absorb force to conform to the trail.

Quoted message said:

Now someone has to explain this for me. Either I picked a very weird
model as an example (possible), or something weird is going on.
Someone must know the details and be willing to explain them to show
how mistaken I was.

If the tubeless tire does weigh more than the tube and tire of the
same construction (iffy--maybe construction is the key difference?),
then the tubeless tire should have worse rolling resistance.

I'll be looking forward to any explanation myself, but having felt the call of
mountain bike fashion myself, I couldn't find it.

Again, lower pressures are possible without pinch flatting or spinning the stem
off and there is a possibility that in very rough or sandy terrain that could
reduce resistance. A guy my size needs to protect his rims and I don't see it
doing me any good.

But there is no weight advantage in either UST, Stan's or the popular "ghetto"
conversions.

Ron

Mark Hickey said:

Quoted message said:

Er, yes, but why does a tubeless tire apparently weigh more than the
same model with a tube?

<snip volumes of data>

<snip>

Quoted message said:

One could ask an even more appropriate question - "why even HAVE
tubeless tires in the first place". As near as I can tell, the answer
is the same as for many other "advancements" in the bike business...

Because we had a solution in search of a problem that doesn't exist.

Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $795 ti frame

My impression (and it could be off whack - I've been away from MTBs for
quite a while) is that the tubeless tires are mainly used for downhill
work, where weight is less of an issue. They're supposed to be less
prone to snake-bite punctures (a common problem in downhill racing),
because the whole casing needs to be bitten, not just the tube as in a
convention tyre-n-tube combo.

Users of cross country MTB bikes are more weight concious than their
ski-lift using downhill brethern, and generally require less tyre
volume anyway.

Hence, based on their intended usage, conventional tyres tend to be
lower volume and lighter than the larger volume, and heavier tubeless
ones.

That's my understanding of how it started off - I don't know how far
tubeless tyres have penetrated into the cross-country market since
then.

bookieb

bookieb said:

Mark Hickey said:

Quoted message said:

Er, yes, but why does a tubeless tire apparently weigh more than the
same model with a tube?

<snip volumes of data>

<snip>

Quoted message said:

One could ask an even more appropriate question - "why even HAVE
tubeless tires in the first place". As near as I can tell, the answer
is the same as for many other "advancements" in the bike business...

Because we had a solution in search of a problem that doesn't exist.

Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $795 ti frame

<snips lot's of own aimless rambling text>

Quoted message said:

That's my understanding of how it started off - I don't know how far
tubeless tyres have penetrated into the cross-country market since
then.

bookieb

Incidentally, I agree. "Solution in search of a problem" is exactly
what occurred to me in respect of this particular "innovation".

bookieb

Quoted message said:

On Thu, 03 Aug 2006 21:45:03 -0700, Mark Hickey <[email hidden]>

Quoted message said:

Quoted message said:

I'm baffled--a tube and tire weigh less than a tubeless tire of the
same model in the bicycle world.

Carl, what are we gonna do with you? You are well-read, but you gotta
pick up a couple books on marketing.

It doesn't matter what something actually WEIGHS - it only matters
that it's perceived as "lighter"... facts seldom enter into these
decisions (and seemingly are becoming less and less important in
general).

It's like 1-1/8" headsets and stems and forks (which all weigh more
than their perfectly fine 1" brethren), yet the "perception" was that
they allowed the use of some different kind of magic technology that
made 'em lighter - so they sell like hotcakes, even to the
weight-weenie crowd (go figure).

Or how about some of the pedal systems that are actually a few grams
lighter than the typical Look pedals? Of course, the cleats weigh
five times as much as the Look cleats, making the combination much
heavier... but they sell like hotcakes to weight weenies too (at least
they can lift the bike to admire it without the "cleat penalty"😉.

Or maybe adding "lightweight carbon fiber rear ends" to titanium
frames? Just keep 'em away from a scale if you've already bought one.
But perception rules again.

So you get the customer to focus on the fact there's "no tube", put
the real weight in small print or express it in a fraction of a stone
or some other obscure method, or use vague language (... new
ubertubeless wondertire that's 38.77% lighter than the average tires
on bikes in India...).

Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $795 ti frame

Dear Mark,

Er, yes, but why does a tubeless tire apparently weigh more than the
same model with a tube?

A quick look at Performance shows heavily treaded tubeless 26x2 MTB
tires at ponderous weights . . .
750g
790g
780g
700g
750g
700g

Not one under 700 grams.

The heavily treaded tube-using 26x2 tires seem to be bulemic . . .
565g
560g
560g
550g
620g (husky)
520g
570g
820g (wire-bead pig!)
580g (also wire-bead, but obviously eats no candy)
695g (how embarrassing)
495g (see what a 1.9 inch waist will do for you?)
500g (smaller knobs help, too)
810g (hulking 2.3-inch big-knob porker)
480g (very sparse knobs)
465g (full 2.1 inch, big, close-set knobs--oddly light)
680g
780g (2.5-inch mammoth)
345g Kenda Klimax "world's lightest mountain tire" 1.95 wide

Looks like around 600 grams.

Again, the apparently identical IRC Mibro tubeless and tube at
Performance, same width, kevlar, tpi, psi, and tread pattern:

Tubeless:
Weight: 770g
Size(S): 26 x 2.25
TPI: 66
Bead: Kevlar - Folding
Max PSI: 50
http://www.performancebike.com/shop/profile.cfm?SKU=20046&subcategory_ID=5430

Tube:
Bead: Kevlar - Folding
Max PSI: 50
Weight: 590g
Size(S): 26 x 2.25
TPI: 66
http://www.performancebike.com/shop/profile.cfm?SKU=20047&subcategory_ID=5430

What are the tubeless tires eating that makes their butts look so big?

I'd boil it down to the oversimplified version and then let one of our staff
propeller heads explain what I've missed:

It takes X mass of rubber and windings to make a structurally sound mountain
bike tire that holds air using presently available materials and practice.

It's that simple. Absent any new technology, they have to use as much rubber as
the other style.

BTW, the UST rims also weigh more.

Ron

Mark Hickey said:

Quoted message said:

I'm baffled--a tube and tire weigh less than a tubeless tire of the
same model in the bicycle world.

Carl, what are we gonna do with you? You are well-read, but you gotta
pick up a couple books on marketing.

It doesn't matter what something actually WEIGHS - it only matters
that it's perceived as "lighter"... facts seldom enter into these
decisions (and seemingly are becoming less and less important in
general).

It's like 1-1/8" headsets and stems and forks (which all weigh more
than their perfectly fine 1" brethren), yet the "perception" was that
they allowed the use of some different kind of magic technology that
made 'em lighter - so they sell like hotcakes, even to the
weight-weenie crowd (go figure).

Or how about some of the pedal systems that are actually a few grams
lighter than the typical Look pedals? Of course, the cleats weigh
five times as much as the Look cleats, making the combination much
heavier... but they sell like hotcakes to weight weenies too (at least
they can lift the bike to admire it without the "cleat penalty"😉.

Same deal with saddles lately. Shorts are getting thicker, with gel even, and
saddles are thinner.

Ron

RonSonic said:

I'd boil it down to the oversimplified version and then let one of our staff
propeller heads explain what I've missed:

It takes X mass of rubber and windings to make a structurally sound mountain
bike tire that holds air using presently available materials and practice.

It's that simple. Absent any new technology, they have to use as much rubber as
the other style.

BTW, the UST rims also weigh more.

Ron

Dear Ron,

Er, so why do the tubeless appear to weigh more than the tube plus a
tube?

Cheers,

Carl Fogel

RonSonic said:

Quoted message said:

RonSonic said:

On Thu, 03 Aug 2006 12:43:33 -0600, [email hidden] wrote:

>On 3 Aug 2006 08:23:41 -0700, "newsboy" <[email hidden]> wrote:
>
>>Richard Cunningham, the editor of Mountain Bike Action, makes the
>>following statement in a bike test."Converting the tires to tubless,
>>would greatly improve the Santa Cruz's rolling resistance and boost
>>it's climbing potential as well"
>>Assuming equal tires, tread paterns,and inflation pressure, is this a
>>true statement. If it is true, by what mechanism is performance
>>increased?
>
>Dear Newsboy,
>
>Leave out "greatly" and it's a reasonable claim.
>
>Basically, the weight of the tire is a good indicator of its rolling
>resistance--the more material squashed out of shape, the greater the
>frictional losses.
>
>The tube is flattened so hard against the inside of the tire that it
>effectively becomes part of the tire--more material.
>
>Lose the tube, and you lose some material. Less material, less rolling
>resistance.

What makes you think a UST tire weighs less than a conventional tire plus tube?

[snip]

Dear Ron,

Ignorance, as Johnson said, pure ignorance.

You're not only right, you're righter than your comment seems to
indicate.

The closest that I could find to the same model with the specs and the
same tread in both tube and tubeless was the IRC Mibro at Peformance:
The tread patterns look identical (some other tube/tubeless pairs that
I compared had similar model names, but very different tread).

snipped refs

Quoted message said:

Same max psi, same width, same tpi, same kevlar, same model, same
tread . . .

But the tubeless model weighs 180 grams more than the tube model!

Performance sells house-brand 26x2.1 tubes that weigh 200, 130, and 99
grams, including the valves.

I'm baffled--a tube and tire weigh less than a tubeless tire of the
same model in the bicycle world.

This is not some unique or uncharacteristic specimen. It's like that pretty much
across the board.

Quoted message said:

It's as if they added a whole tube to the inside of the tubeless tire
(even though the rim-side section isn't needed) and then added even
more.

It isn't only the tire side, but there is a required rim strip to seal the spoke
holes and in the case of a conversion like stan's to wrap around the rim and
seal the bead. Don't neglect the slime-like sealant that is generally required.

But, yes there's almost an entire inner tube's worth of additional rubber on the
tire carcass itself. That will absorb force to conform to the trail.

Quoted message said:

Now someone has to explain this for me. Either I picked a very weird
model as an example (possible), or something weird is going on.
Someone must know the details and be willing to explain them to show
how mistaken I was.

If the tubeless tire does weigh more than the tube and tire of the
same construction (iffy--maybe construction is the key difference?),
then the tubeless tire should have worse rolling resistance.

I'll be looking forward to any explanation myself, but having felt the call of
mountain bike fashion myself, I couldn't find it.

Again, lower pressures are possible without pinch flatting or spinning the stem
off and there is a possibility that in very rough or sandy terrain that could
reduce resistance. A guy my size needs to protect his rims and I don't see it
doing me any good.

But there is no weight advantage in either UST, Stan's or the popular "ghetto"
conversions.

Ron

Dear Ron,

As I understand the weights, the same model of tubeless tire weighs
more than the tube version plus a heavy inner tube.

And as I understand things, the rim strip, metal rim, and possibly
even the tubeless valve that fits into the rim aren't included in the
tubeless tire's weight.

If all they did was glue the equivalent of a tube to the inside, they
could leave out the substantial rim-side section of the tube and thus
save weight.

So we're both left wondering why the tubeless weighs so much.

Cheers,

Carl Fogel

Quoted message said:

RonSonic said:

Quoted message said:

On Thu, 03 Aug 2006 21:35:13 -0400, RonSonic
<[email hidden]> wrote:

>On Thu, 03 Aug 2006 12:43:33 -0600, [email hidden] wrote:
>
>>On 3 Aug 2006 08:23:41 -0700, "newsboy" <[email hidden]> wrote:
>>
>>>Richard Cunningham, the editor of Mountain Bike Action, makes the
>>>following statement in a bike test."Converting the tires to tubless,
>>>would greatly improve the Santa Cruz's rolling resistance and boost
>>>it's climbing potential as well"
>>>Assuming equal tires, tread paterns,and inflation pressure, is this a
>>>true statement. If it is true, by what mechanism is performance
>>>increased?
>>
>>Dear Newsboy,
>>
>>Leave out "greatly" and it's a reasonable claim.
>>
>>Basically, the weight of the tire is a good indicator of its rolling
>>resistance--the more material squashed out of shape, the greater the
>>frictional losses.
>>
>>The tube is flattened so hard against the inside of the tire that it
>>effectively becomes part of the tire--more material.
>>
>>Lose the tube, and you lose some material. Less material, less rolling
>>resistance.
>
>What makes you think a UST tire weighs less than a conventional tire plus tube?

[snip]

Dear Ron,

Ignorance, as Johnson said, pure ignorance.

You're not only right, you're righter than your comment seems to
indicate.

The closest that I could find to the same model with the specs and the
same tread in both tube and tubeless was the IRC Mibro at Peformance:
The tread patterns look identical (some other tube/tubeless pairs that
I compared had similar model names, but very different tread).

snipped refs

Quoted message said:

Same max psi, same width, same tpi, same kevlar, same model, same
tread . . .

But the tubeless model weighs 180 grams more than the tube model!

Performance sells house-brand 26x2.1 tubes that weigh 200, 130, and 99
grams, including the valves.

I'm baffled--a tube and tire weigh less than a tubeless tire of the
same model in the bicycle world.

This is not some unique or uncharacteristic specimen. It's like that pretty much
across the board.

Quoted message said:

It's as if they added a whole tube to the inside of the tubeless tire
(even though the rim-side section isn't needed) and then added even
more.

It isn't only the tire side, but there is a required rim strip to seal the spoke
holes and in the case of a conversion like stan's to wrap around the rim and
seal the bead. Don't neglect the slime-like sealant that is generally required.

But, yes there's almost an entire inner tube's worth of additional rubber on the
tire carcass itself. That will absorb force to conform to the trail.

Quoted message said:

Now someone has to explain this for me. Either I picked a very weird
model as an example (possible), or something weird is going on.
Someone must know the details and be willing to explain them to show
how mistaken I was.

If the tubeless tire does weigh more than the tube and tire of the
same construction (iffy--maybe construction is the key difference?),
then the tubeless tire should have worse rolling resistance.

I'll be looking forward to any explanation myself, but having felt the call of
mountain bike fashion myself, I couldn't find it.

Again, lower pressures are possible without pinch flatting or spinning the stem
off and there is a possibility that in very rough or sandy terrain that could
reduce resistance. A guy my size needs to protect his rims and I don't see it
doing me any good.

But there is no weight advantage in either UST, Stan's or the popular "ghetto"
conversions.

Ron

Dear Ron,

As I understand the weights, the same model of tubeless tire weighs
more than the tube version plus a heavy inner tube.

And as I understand things, the rim strip, metal rim, and possibly
even the tubeless valve that fits into the rim aren't included in the
tubeless tire's weight.

If all they did was glue the equivalent of a tube to the inside, they
could leave out the substantial rim-side section of the tube and thus
save weight.

That's how the no-tubes conversions work, take essentially half an innertube and
stretch it around the rim and over the bead. Put the tire on and insert latex
sealant and air. The 4 - 8 fluid ounces of sealant is water based and not light
itself.

Quoted message said:

So we're both left wondering why the tubeless weighs so much.

Many of them are oriented toward rougher riding than the lighter XC tires in the
500ish gram range. Maybe someone here with real experience with the things can
fill some of this in. Where's that newly promoted Squid, they're supposed to
know about this stuff.

Ron

Quoted message said:

If the tubeless tire does weigh more than the tube and tire of the
same construction (iffy--maybe construction is the key difference?),
then the tubeless tire should have worse rolling resistance.

i can assure you that the construction is quite difference. you
can decrease rolling resistance by inflating the tire to a higher
pressure.

On Fri, 04 Aug 2006 17:12:01 -0800, [email hidden]

(Dennis P. Harris) said:

Quoted message said:

If the tubeless tire does weigh more than the tube and tire of the
same construction (iffy--maybe construction is the key difference?),
then the tubeless tire should have worse rolling resistance.

i can assure you that the construction is quite difference.

Dear Dennis,

So what's the difference?

Cheers,

Carl Fogel