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isn't this stealing...?
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well on your conscious be it
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why would anyone care if wiggle lost some money?!
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have been told off this morning for being rude about council estate girls
so I want to see how it feels to be all self rightious
why not give wiggle a call and ask them if it was a genuine mistake or not -
keep em thiner tiers= less rolling resistance= good.
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wider tire = more surface area = more likely to pick up glass/ thorns then a thiner tyre.
keep them.
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chris crash keep em thiner tiers= less rolling resistance= good.
Contentious.
Thinner tyres = more rolling resistance / less aerodynamic drag.
http://www.roadcyclinguk.com/news/article.asp?SP=&v=2&UAN=1929
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eh?
"Despite this, the 25c format is too fat for racing. The width of the tyre increases frontal area and air drag, ruling it out for time trials on smooth roads. The increased weight is a significant handicap in any acceleration, so they aren't much use in a bunch. For training, touring and randonnees, however, the fatter tyre is simply a superior option, provided it will fit in your frame. "
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That makes sense, doesn't it? If you're rolling along in the 25mph+ zone, you'll notice a bit of extra drag on 25s, and if you want to sprint, obviously they're not going to spin up as quickly (like the way deep section rims are sluggish to accelerate).
But just rolling along, there's less rolling resistance, due to the way the tyre deforms, physics of contact patch - wider tyre has shorter/wider contact patch, and it's the length of patch that effects rolling resistance.
It's all pretty academic really. I ride 25s at 80/85psi in the winter due to the comfort, and the extra bit of lateral grip on sketchy surfaces. And I'd use them in Paris-Roubaix type rides... if I had the talent to race, or the money/time to randonnée :)
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"wider tyre has shorter/wider contact patch"
Is that true? I'd've thought that it would be the wheels size (diameter) that affects this, and since we're comparing 700s of different widths wouldn't they have the same length contact patch? I mean...same size, both 360 degrees?
I'm sure this has got more to do with me not knowing enough about tyres. I understand thinner tyres will be faster for racing, but i don't get the physics which explains why the converse should be true at slower speeds.
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This sort of covers it: http://www.slowtwitch.com/mainheadings/techctr/wheels_tires.html
Quite boring though, isn't it.
I experimented with lower pressures on hillclimbs one year. Running 80psi in both front and rear (23s). It definitely helped reduce wheelspin on wet/leafy/greasy surfaces, but I think it was scrubbing my speed due to my extra weight (whilst standing) over the front wheel - just felt too squirmy, and cost me 5 to 10 seconds over 2mins.
I think wet/slippery hillcimbs are the only occassion I'd consider running more pressure in the front tyre than the rear. Oh, and I'd always be on 23s of course, due to acceleration and weight :)
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BringMeMyFix
But just rolling along, there's less rolling resistance, due to the way the tyre deforms, physics of contact patch - wider tyre has shorter/wider contact patch, and it's the length of patch that effects rolling resistance.I'm not so sure about that, the deformation of the tyre would depend allot on the amount of weight on the bike, and:
"Standard friction equation
The standard equation for determining the resistive force of friction when trying to slide two solid objects together states that the force of friction equals the coefficient friction times the normal force pushing the two objects together. This equation is written as
Fr = ?N
where:
* Fr is the resistive force of friction * ? is the coefficient of friction for the two surfaces (Greek letter "mu") * N is the normal or perpendicular force pushing the two objects together * ?N is ? times NFr and N are measured in units of force, which are pounds or newtons. ? is a number between 0 (zero) and ? (infinity).
Applies to static and kineticThis equation applies to both static and kinetic sliding friction. Static friction is the friction before an object starts to slide. Kinetic friction is the friction when the object is actually moving or sliding.
Static friction and kinetic friction have different coefficient of friction values.
Independent of area for sliding hard surfacesAn interesting result of this equation is that in the case of sliding friction of hard surfaces, the friction is independent of the area of the surfaces. In other words, it is just as difficult to move a 1 square-cm object as a 1 square-meter object, if they both are pressed to the surface with the same amount of force.
This is not intuitive. You would think that there is more friction when the surfaces are larger, but the friction equation states otherwise. You can verify this fact with experiments.
Soft, adhesion, rolling and fluidIn situations where the surfaces deform or there is molecular adhesion, the friction is not independent of the areas in contact. In these cases surface area usually comes into play. This is also true for rolling and fluid friction.
When solid surfaces are soft and deform or when one material is a fluid, the shape of the solid object may be a factor.
Although the standard friction equation still holds, the coefficient of friction may have area, shape and other factors included in it....
...Coefficient when surfaces not hard and sliding
In the case where a surface is soft, there is molecular adhesion, and in rolling and fluid friction, the coefficient of friction is not a simple number. The coefficient may be dependent on the area of the surfaces, the amount of deformation, the amount of adhesion, the shape of the surfaces, the radius of the wheel or the viscosity of the fluid.
What this means is that although the standard friction equation holds in these cases, the coefficient of friction will only hold for a specific configuration. In other words, you can't accurately give something like the coefficient of rolling friction for a rubber tire on pavement without stating the type of rubber, area on the pavement, inflation of the tire, and its tread pattern."
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Oh right.
the-smiling-buddha
photoben
kboy
eeehhhh
runcible_rakan
CHUG_IT
chris_crash
BringMeMyFix
tomasito-
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About
Wiggle's Cock Up=your Saving..
Posted by
@clefty
Hello gang,
Wiggle cocked up my order for some Rubino's albeit in my favour. I ordered a set of regular red/black 700 x 25 for my road bike at £16.99, but they sent me a set of pro 700 x 23 worth £28.99. I initially was going to send them back as I defo want 25's but then I thought HANG ON, why shouldn't i (or someone else on this forum) take advantage of this cock up.
So with that in mind, if someone wants to buy me a set of red and black regular rubinos 700 x 25, they can have the set of pros saving yourself 8 quid. If not I will just send them back to wiggle - but seems a shame not to take advantage..
whisper me if you're interested