Sul canale 17 onestamente non so che dire...
"Cerchiamo nella bdc/componenti quello che non troviamo nelle gambe!!!"
"Chi non è pieno si ritira" Graziano Gasparre
Nuove Fulcrum Zero 2017
- Creatore Discussione fabbio
- Data di inizio
Sul canale 17 onestamente non so che dire...
"Cerchiamo nella bdc/componenti quello che non troviamo nelle gambe!!!"
"Chi non è pieno si ritira" Graziano Gasparre
Ragazzi, è inutile farci tanti problemi, il nuovo riferimento è il 17 c...
si questo senza dubbio, volendo o no sarà così. più che altro si discuteva sui vantaggi/svantaggi relativi al suo nuovo cerchio, ed il costo..
cmq sembra che le nuove shimano C24 mantengano il 15C (l'ho letto da un altro utente poco fa)
Interessante....
Rotating weight is crucial
An ounce off the wheels is worth a pound off the frame, goes the old saying, implying that rotating weight, especially on the wheels, is supremely important. The claim is sometimes laid out in less hyperbolic terms that weight on the wheels counts twice because when you accelerate you have to get it both spinning and moving forward.
Problem is, its not true. In 2001 bike engineer Kraig Willett analysed the forces on wheels (link is external) and concluded:
When evaluating wheel performance, wheel aerodynamics are the most important, distantly followed by wheel mass. Wheel inertia effects in all cases are so small that they are arguably insignificant.
The idea that rotating mass is important comes from the belief that wheel inertia matters, because its inertia that has to be overcome to accelerate a wheel. But Willett clearly demonstrates that wheel inertia doesnt matter, so rotating weight is also relatively unimportant.
Why not? Well, you don't do much accelerating when you ride a bike, and even when you do the acceleration is relatively low, so the power expended accelerating a bike with heavy wheels is only fractionally higher than that needed for light wheels. Overall weight matters when youre climbing, but even thats not as big a factor as people imagine and its a lot cheaper to save weight off your middle than the bike.
In fact you spend most of your time, and therefore effort, shoving the air out of the way, and thats a far better basis for choosing wheels. The roughly tenfold difference in the effect of aerodynamics versus total mass means youre far better off with a pair of good aero wheels than a pair of light ones.
Narrow tyres are faster
You can see where this one comes from. In cycling, smaller things are lighter and lighter things make you go faster, right? Well, no, not for tyres. Countless measurements have demonstrated beyond doubt that rolling resistance of tyres is lower if the tyres are wider, as long as the construction carcass thickness and materials, tread rubber and depth etc is identical.
But is that the whole story? What about weight and aerodynamics?
As discussed above, weight, even rotating weight, has a much lower effect on performance than people think, so the few grams difference between 23mm and 25mm tyres is immaterial.
Were not aware of any detailed modelling of the aerodynamic effects of fatter tyres, but lets have a bit of a stab at it. Aerodynamic drag arises from an objects frontal area and its drag coefficient.
Drag coefficient depends on an objects shape and how air flows over its surface. A very aerodynamic shape such as a smooth wing might have a drag coefficient of 0.005, while a bricks is more like 2.0.
Multiplying the drag coefficient by the frontal area gives you the aerodynamic drag, so drag force increases as, say, a tyre gets wider.
According to CyclingPowerLab (link is external), the frontal area of a cyclist in the drops is about 0.36m². The change from 23mm to 25mm tyres adds 0.001436m², an increase of 0.4%. Thats the increase in power youll need to maintain any given speed. It takes 102 watts to maintain 18 miles per hour in this scenario, which increases to 102.5 watts with the fatter tyres.
According to BicycleRollingResistance.com (link is external), theres a 0.3 watt difference in rolling resistance per tyre at this speed between 23mm and 25mm versions of Continental GP4000s II tyres at 120psi. The half-watt increase in aerodynamic drag is therefore almost exactly countered by the decrease in rolling resistance.
The problem here is that youre not going to get the other benefit of fat tyres a softer ride if you keep the pressure the same. If you do reduce the pressure, then the rolling resistance goes up too, and you end up with slightly more total resistance.
With 28mm tyres it turns out you have a bit more leeway and can drop the pressure a little. At 100psi our 28mm GP4000s IIs have 0.5 watts per tyre less resistance than 23mm tyres at 120psi, and one watt more aerodynamic drag.
Narrow tyres, then, faster or slower? The answer, it turns out, is it depends. The total aerodynamic and rolling resistance depends on tyre size and pressure, and which is faster changes with how you fine-tune those variables.
An extra complication we havent mentioned yet is speed. As you go faster aerodynamic drag increases more than rolling resistance. At finishing sprint and time trial speeds, youre almost certainly better off with narrow tyres.
If you dont race, though, you might have noticed that were talking about small differences in resistance. A 28mm GP4000s II at 80psi has the same rolling resistance as a 23mm at 120psi. Does the extra watt of air resistance matter? Its definitely not a difference you can feel (the threshold for that is 5-10 watts depending on the individual) and its going to make a tiny difference to your ride time even on a long ride. You might well decide the comfort is more than worth it.
http://road.cc/content/feature/1944...-dead-frames-skinny-tyres-rotating-weight-and
Quindi vai di C17
Rotating weight is crucial
An ounce off the wheels is worth a pound off the frame, goes the old saying, implying that rotating weight, especially on the wheels, is supremely important. The claim is sometimes laid out in less hyperbolic terms that weight on the wheels counts twice because when you accelerate you have to get it both spinning and moving forward.
Problem is, its not true. In 2001 bike engineer Kraig Willett analysed the forces on wheels (link is external) and concluded:
When evaluating wheel performance, wheel aerodynamics are the most important, distantly followed by wheel mass. Wheel inertia effects in all cases are so small that they are arguably insignificant.
The idea that rotating mass is important comes from the belief that wheel inertia matters, because its inertia that has to be overcome to accelerate a wheel. But Willett clearly demonstrates that wheel inertia doesnt matter, so rotating weight is also relatively unimportant.
Why not? Well, you don't do much accelerating when you ride a bike, and even when you do the acceleration is relatively low, so the power expended accelerating a bike with heavy wheels is only fractionally higher than that needed for light wheels. Overall weight matters when youre climbing, but even thats not as big a factor as people imagine and its a lot cheaper to save weight off your middle than the bike.
In fact you spend most of your time, and therefore effort, shoving the air out of the way, and thats a far better basis for choosing wheels. The roughly tenfold difference in the effect of aerodynamics versus total mass means youre far better off with a pair of good aero wheels than a pair of light ones.
Narrow tyres are faster
You can see where this one comes from. In cycling, smaller things are lighter and lighter things make you go faster, right? Well, no, not for tyres. Countless measurements have demonstrated beyond doubt that rolling resistance of tyres is lower if the tyres are wider, as long as the construction carcass thickness and materials, tread rubber and depth etc is identical.
But is that the whole story? What about weight and aerodynamics?
As discussed above, weight, even rotating weight, has a much lower effect on performance than people think, so the few grams difference between 23mm and 25mm tyres is immaterial.
Were not aware of any detailed modelling of the aerodynamic effects of fatter tyres, but lets have a bit of a stab at it. Aerodynamic drag arises from an objects frontal area and its drag coefficient.
Drag coefficient depends on an objects shape and how air flows over its surface. A very aerodynamic shape such as a smooth wing might have a drag coefficient of 0.005, while a bricks is more like 2.0.
Multiplying the drag coefficient by the frontal area gives you the aerodynamic drag, so drag force increases as, say, a tyre gets wider.
According to CyclingPowerLab (link is external), the frontal area of a cyclist in the drops is about 0.36m². The change from 23mm to 25mm tyres adds 0.001436m², an increase of 0.4%. Thats the increase in power youll need to maintain any given speed. It takes 102 watts to maintain 18 miles per hour in this scenario, which increases to 102.5 watts with the fatter tyres.
According to BicycleRollingResistance.com (link is external), theres a 0.3 watt difference in rolling resistance per tyre at this speed between 23mm and 25mm versions of Continental GP4000s II tyres at 120psi. The half-watt increase in aerodynamic drag is therefore almost exactly countered by the decrease in rolling resistance.
The problem here is that youre not going to get the other benefit of fat tyres a softer ride if you keep the pressure the same. If you do reduce the pressure, then the rolling resistance goes up too, and you end up with slightly more total resistance.
With 28mm tyres it turns out you have a bit more leeway and can drop the pressure a little. At 100psi our 28mm GP4000s IIs have 0.5 watts per tyre less resistance than 23mm tyres at 120psi, and one watt more aerodynamic drag.
Narrow tyres, then, faster or slower? The answer, it turns out, is it depends. The total aerodynamic and rolling resistance depends on tyre size and pressure, and which is faster changes with how you fine-tune those variables.
An extra complication we havent mentioned yet is speed. As you go faster aerodynamic drag increases more than rolling resistance. At finishing sprint and time trial speeds, youre almost certainly better off with narrow tyres.
If you dont race, though, you might have noticed that were talking about small differences in resistance. A 28mm GP4000s II at 80psi has the same rolling resistance as a 23mm at 120psi. Does the extra watt of air resistance matter? Its definitely not a difference you can feel (the threshold for that is 5-10 watts depending on the individual) and its going to make a tiny difference to your ride time even on a long ride. You might well decide the comfort is more than worth it.
http://road.cc/content/feature/1944...-dead-frames-skinny-tyres-rotating-weight-and
Quindi vai di C17
Shimano che non è l'ultima arrivata non segue così facilmente le "mode" ma pondera sempre molto cosa deve fare ...
"Cerchiamo nella bdc/componenti quello che non troviamo nelle gambe!!!"
"Chi non è pieno si ritira" Graziano Gasparre
Beh con campagnolo possiamo dire che se la giocano!:rosik:
Ad ogni modo solo le nuove Dura Ace C24 sono C15, mentre le C40 e C60 sono C17...quindi...
Ultima modifica:
qui però la domanda sporge spontanea.. perché le C24 rimangono con il "vecchio cerchio"?
C40 e C60 avranno sempre la versione copertoncino o restano le "vecchie" 9000??
su bdc mag presentano la nuova racing zero con cerchio 17c
la "sacca d'aria" che si crea con i 25 sul cerchio 15 c mi mancava
adesso anche i più perplessi nel passaggio a cerchi da 17c, pur di non avere la sacca d'aria, abbandoneranno i 15c
:rosik:
la "sacca d'aria" che si crea con i 25 sul cerchio 15 c mi mancava
adesso anche i più perplessi nel passaggio a cerchi da 17c, pur di non avere la sacca d'aria, abbandoneranno i 15c
:rosik:
su bdc mag presentano la nuova racing zero con cerchio 17c
la "sacca d'aria" che si crea con i 25 sul cerchio 15 c mi mancava
adesso anche i più perplessi nel passaggio a cerchi da 17c, pur di non avere la sacca d'aria, abbandoneranno i 15c
:rosik:
In realtà le fulcrum zero rimarranno in produzione con i cerchi da 15 a cui si affiancherà le zero competition da 17, oltre alle Carbon e nite , non è altro che un allargamento di gamma per soddisfare tutti i potenziali acquirenti!
"Cerchiamo nella bdc/componenti quello che non troviamo nelle gambe!!!"
"Chi non è pieno si ritira" Graziano Gasparre
Comunque la si pensi il canale 17C è già di fatto lo standard di riferimento.
DT Swiss ha presentanto le sue nuove ruote carbon per copertoncino "RC38 SPLINE® C Mon Chasseral" ed hanno canale 15c.
Quasi tutto il resto della gamma però ha canale da 18/19mm.
Ho testè preso un set di conti gp4000s2 da 23mm da usare con le mie R1.
E per inciso mode o non mode, sacche d'aria e non, se mai mi capitasse "l'occasione" con ruote 17c - tipo Fulcrum R0Carbon - monterei senza problemi questi copertoni appena presi come molti hanno già fatto...:-)
DT Swiss ha presentanto le sue nuove ruote carbon per copertoncino "RC38 SPLINE® C Mon Chasseral" ed hanno canale 15c.
Quasi tutto il resto della gamma però ha canale da 18/19mm.
Ho testè preso un set di conti gp4000s2 da 23mm da usare con le mie R1.
E per inciso mode o non mode, sacche d'aria e non, se mai mi capitasse "l'occasione" con ruote 17c - tipo Fulcrum R0Carbon - monterei senza problemi questi copertoni appena presi come molti hanno già fatto...:-)
Spesso i rivenditori non sanno o fanno finta di non sapere .
Comunque ribadisco la fulcrum avrà a catalogo 4 zero, cioè le zero c15, le nite, le Carbon e le conpetition c17!
"Cerchiamo nella bdc/componenti quello che non troviamo nelle gambe!!!"
"Chi non è pieno si ritira" Graziano Gasparre
Interessante....
Rotating weight is crucial
An ounce off the wheels is worth a pound off the frame, goes the old saying, implying that rotating weight, especially on the wheels, is supremely important. The claim is sometimes laid out in less hyperbolic terms that weight on the wheels counts twice because when you accelerate you have to get it both spinning and moving forward.
Problem is, its not true. In 2001 bike engineer Kraig Willett analysed the forces on wheels (link is external) and concluded:
When evaluating wheel performance, wheel aerodynamics are the most important, distantly followed by wheel mass. Wheel inertia effects in all cases are so small that they are arguably insignificant.
The idea that rotating mass is important comes from the belief that wheel inertia matters, because its inertia that has to be overcome to accelerate a wheel. But Willett clearly demonstrates that wheel inertia doesnt matter, so rotating weight is also relatively unimportant.
Why not? Well, you don't do much accelerating when you ride a bike, and even when you do the acceleration is relatively low, so the power expended accelerating a bike with heavy wheels is only fractionally higher than that needed for light wheels. Overall weight matters when youre climbing, but even thats not as big a factor as people imagine and its a lot cheaper to save weight off your middle than the bike.
In fact you spend most of your time, and therefore effort, shoving the air out of the way, and thats a far better basis for choosing wheels. The roughly tenfold difference in the effect of aerodynamics versus total mass means youre far better off with a pair of good aero wheels than a pair of light ones.
Narrow tyres are faster
You can see where this one comes from. In cycling, smaller things are lighter and lighter things make you go faster, right? Well, no, not for tyres. Countless measurements have demonstrated beyond doubt that rolling resistance of tyres is lower if the tyres are wider, as long as the construction carcass thickness and materials, tread rubber and depth etc is identical.
But is that the whole story? What about weight and aerodynamics?
As discussed above, weight, even rotating weight, has a much lower effect on performance than people think, so the few grams difference between 23mm and 25mm tyres is immaterial.
Were not aware of any detailed modelling of the aerodynamic effects of fatter tyres, but lets have a bit of a stab at it. Aerodynamic drag arises from an objects frontal area and its drag coefficient.
Drag coefficient depends on an objects shape and how air flows over its surface. A very aerodynamic shape such as a smooth wing might have a drag coefficient of 0.005, while a bricks is more like 2.0.
Multiplying the drag coefficient by the frontal area gives you the aerodynamic drag, so drag force increases as, say, a tyre gets wider.
According to CyclingPowerLab (link is external), the frontal area of a cyclist in the drops is about 0.36m². The change from 23mm to 25mm tyres adds 0.001436m², an increase of 0.4%. Thats the increase in power youll need to maintain any given speed. It takes 102 watts to maintain 18 miles per hour in this scenario, which increases to 102.5 watts with the fatter tyres.
According to BicycleRollingResistance.com (link is external), theres a 0.3 watt difference in rolling resistance per tyre at this speed between 23mm and 25mm versions of Continental GP4000s II tyres at 120psi. The half-watt increase in aerodynamic drag is therefore almost exactly countered by the decrease in rolling resistance.
The problem here is that youre not going to get the other benefit of fat tyres a softer ride if you keep the pressure the same. If you do reduce the pressure, then the rolling resistance goes up too, and you end up with slightly more total resistance.
With 28mm tyres it turns out you have a bit more leeway and can drop the pressure a little. At 100psi our 28mm GP4000s IIs have 0.5 watts per tyre less resistance than 23mm tyres at 120psi, and one watt more aerodynamic drag.
Narrow tyres, then, faster or slower? The answer, it turns out, is it depends. The total aerodynamic and rolling resistance depends on tyre size and pressure, and which is faster changes with how you fine-tune those variables.
An extra complication we havent mentioned yet is speed. As you go faster aerodynamic drag increases more than rolling resistance. At finishing sprint and time trial speeds, youre almost certainly better off with narrow tyres.
If you dont race, though, you might have noticed that were talking about small differences in resistance. A 28mm GP4000s II at 80psi has the same rolling resistance as a 23mm at 120psi. Does the extra watt of air resistance matter? Its definitely not a difference you can feel (the threshold for that is 5-10 watts depending on the individual) and its going to make a tiny difference to your ride time even on a long ride. You might well decide the comfort is more than worth it.
http://road.cc/content/feature/1944...-dead-frames-skinny-tyres-rotating-weight-and
Quindi vai di C17
Oppure di C15 con i 25mm.
A parte l'ironia, davvero non credo che per un amatore ci sia una differenza apprezzabile. Mi soffermerei piuttosto sul confort offerto dai copertoni più larghi, una differenza molto più significativa per le nostre pedalate di tutti i giorni... anche sui C15!
Speriamo.
Al momento però, la cosa un po' sconcertante a mio avviso è che leggo qui su BDC mag e altrove articoli su R0 17c ma sul sito fulcrum...niente.
Speriamo.
Al momento però, la cosa un po' sconcertante a mio avviso è che leggo qui su BDC mag e altrove articoli su R0 17c ma sul sito fulcrum...niente.
Un po di pazienza [emoji16]
"Cerchiamo nella bdc/componenti quello che non troviamo nelle gambe!!!"
"Chi non è pieno si ritira" Graziano Gasparre
quindi delle nuove R0 da 17C "normali" ci saranno solo le competition? quelle con il raggio e qualche particolare rosso giusto?
A quanto pare si
"Cerchiamo nella bdc/componenti quello che non troviamo nelle gambe!!!"
"Chi non è pieno si ritira" Graziano Gasparre
Giobbe docet :-)
Davvero però non trovi un po' strano che la novità riguardante la ruota in alluminio (forse) più diffusa sia presente ovunque tranne che sul sito fulcrum?
A me sì e francamente mi sfugge la ratio di tutto ciò...
da quello che leggo su bdc-mag e dalle relative foto sembrerebbe ci sia anche una versione normale R0 (per capirci con i raggi tutti neri, e con le grafiche nuove), che praticamente sostituisce l'attuale modello.
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SCOTT ADDICT RC PRO Taglia S (52)
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