P
Pete
Guest
"Mike Vandeman" <[email protected]> wrote in message
news:[email protected]...
> On Tue, 01 Jun 2004 16:18:38 GMT, "Pete" <[email protected]> wrote:
>
> .
> .Gears. Most bikes sold today have multiple gears.
>
> 10, not 15 or 21.
C'mon, Mikey...when was the last time you saw a *new* "10 speed" for sale?
In any event...the number of gears is irrelevant. More gears = less spread
between each one. Top and bottom are still pretty much the same. (Except for
the so-called MegaRange rear cluster with an extra big low gear, found on
many 'city bikes', as well as some mountain bikes)
>
> .Road/City/Hybrid/Comfort/MTB. Irrelevant.
> .Brakes. Most bikes sold today have two brakes. Irrelevant.
> .Frames. Stip a low end road bike, and a low end MTB down to the bare
frame,
> .and I'd be surprised if you found more than a pound or so difference.
Hardly
> .'overbuilt'
>
> If that were true, we wouldn't need mountain bikes. There must be some
> difference, or people would be mountain biking on 10-speeds.
The difference is marketing. What is on display for people to see and buy?
Things shaped like mountain bikes. Never mind that the vast majority never
leave the pavement. Or at most go across the grass in the front yard.
> .> .They *are* road tires, dumdum. They just happen to fit common mountain
> .bike
> .> .rims.
> .>
> .> Implying that they are WIDER than normal road tires, and hence have
more
> .rolling
> .> resistance. DUH!
> .
> .Please show some data illustrating that point. I've posted data to the
> .opposite. Your turn.
>
> Something so obvious doesn't need "data". It is simple physics.
Yes, it IS simple physics.
Simple physics to show that the contact patch will, at a given pressure and
weight, be the same size, no matter how wide the tire.
Simple physics to show that a rounder and shorter contact patch, of the same
area, causes less sidewall deformation, ergo less internal friction, ergo
less rolling resistance.
Not obvious, but simple.
100 pounds per square inch means exactly that. A 100 lb load results in a 1
square inch contact patch. Now....is that patch long and skinny, or wide and
short?
There is specific test data, from multiple sources, that show that wider
tires (of the same construction and pressure) may well have less rolling
resistance than narrower ones. I've posted links showing these tests.
OTOH, as a counter, you can only say "It's obvious". No theory, no
supporting data, no documented tests. Nothing. Just your usual frothing at
the mouth. And as usual, completely wrong in your assumptions.
Thanks for playing, Mikey. This has been fun.
Pete
I apologize to all those still reading this for my semi-annual "poking the
monkey with a stick" exercise. I'll stop now.
news:[email protected]...
> On Tue, 01 Jun 2004 16:18:38 GMT, "Pete" <[email protected]> wrote:
>
> .
> .Gears. Most bikes sold today have multiple gears.
>
> 10, not 15 or 21.
C'mon, Mikey...when was the last time you saw a *new* "10 speed" for sale?
In any event...the number of gears is irrelevant. More gears = less spread
between each one. Top and bottom are still pretty much the same. (Except for
the so-called MegaRange rear cluster with an extra big low gear, found on
many 'city bikes', as well as some mountain bikes)
>
> .Road/City/Hybrid/Comfort/MTB. Irrelevant.
> .Brakes. Most bikes sold today have two brakes. Irrelevant.
> .Frames. Stip a low end road bike, and a low end MTB down to the bare
frame,
> .and I'd be surprised if you found more than a pound or so difference.
Hardly
> .'overbuilt'
>
> If that were true, we wouldn't need mountain bikes. There must be some
> difference, or people would be mountain biking on 10-speeds.
The difference is marketing. What is on display for people to see and buy?
Things shaped like mountain bikes. Never mind that the vast majority never
leave the pavement. Or at most go across the grass in the front yard.
> .> .They *are* road tires, dumdum. They just happen to fit common mountain
> .bike
> .> .rims.
> .>
> .> Implying that they are WIDER than normal road tires, and hence have
more
> .rolling
> .> resistance. DUH!
> .
> .Please show some data illustrating that point. I've posted data to the
> .opposite. Your turn.
>
> Something so obvious doesn't need "data". It is simple physics.
Yes, it IS simple physics.
Simple physics to show that the contact patch will, at a given pressure and
weight, be the same size, no matter how wide the tire.
Simple physics to show that a rounder and shorter contact patch, of the same
area, causes less sidewall deformation, ergo less internal friction, ergo
less rolling resistance.
Not obvious, but simple.
100 pounds per square inch means exactly that. A 100 lb load results in a 1
square inch contact patch. Now....is that patch long and skinny, or wide and
short?
There is specific test data, from multiple sources, that show that wider
tires (of the same construction and pressure) may well have less rolling
resistance than narrower ones. I've posted links showing these tests.
OTOH, as a counter, you can only say "It's obvious". No theory, no
supporting data, no documented tests. Nothing. Just your usual frothing at
the mouth. And as usual, completely wrong in your assumptions.
Thanks for playing, Mikey. This has been fun.
Pete
I apologize to all those still reading this for my semi-annual "poking the
monkey with a stick" exercise. I'll stop now.