En esta entrada voy a analizar a una de las grandes novedades de esta temporada, el primer modelo de una marca especializada en la fabricación mediante impresión en 3D, una técnica que ahora mismo es bastante cara (5.700€...), pero en un futuro será un poco mas accesible y que tiene algunas ventajas respecto a la fabricación tradicional en Fibra de Carbono: No se necesitan moldes y esto permite crear modelos con geometría a la carta y modificaciones rápidas en el diseño. La nueva Robot Bike R160 es un modelo de Enduro con ruedas de 27.5'' y un sistema de suspensión tipo 6-Bar con 160mm de recorrido diseñado por Dave Weagle...
Como podéis ver en la tabla de excel y en las gráficas anteriores el sistema de la nueva Robot Bike R160 tiene una Eficacia de Pedaleo bastante alta, pero los porcentajes de Anti-squat en los desarrollos mas largos son un poco excesivos (+150%). Como es lógico en un cuadro de este tipo todo el mundo va a realizar un montaje "de lujo" y casi todo el mundo utilizará una transmisión tipo 1x12 (Sram Eagle), pero rebajar los porcentajes a un nivel mas adecuado de Anti-squat sigue siendo complicado ya que habría que utilizar unos desarrollos bastante grandes (36T). Otro detalle interesante es que a pesar de la complejidad del sistema, la gráfica de Anti-squat tiene un perfil muy plano, algo que se podría haber conseguido con un sistema mucho mas sencillo. El Pedal-kickback (25º) como era de esperar es muy elevado, mientras que el Brake-squat (69%) se mantiene en un nivel medio, un buen dato si lo comparamos con otros sistemas de Pivote Virtual, aunque las diferencias son mínimas.
En la gráfica del Leverage Ratio vemos como el sistema es muy progresivo (3.15-2.2), unas cifras muy buenas para un modelo de Enduro. En cuanto al amortiguador la marca ofrece varias opciones (RSMP, FFX y FFX2) y en principio creo que el Fox Float X2 es una gran opción, pero lo mas importante es que el amortiguador tiene una medida completamente estandar (216x63mm) por lo que el propietario siempre va a tener la opción de montar otro amortiguador.
Un saludo.
Como podéis ver en la tabla de excel y en las gráficas anteriores el sistema de la nueva Robot Bike R160 tiene una Eficacia de Pedaleo bastante alta, pero los porcentajes de Anti-squat en los desarrollos mas largos son un poco excesivos (+150%). Como es lógico en un cuadro de este tipo todo el mundo va a realizar un montaje "de lujo" y casi todo el mundo utilizará una transmisión tipo 1x12 (Sram Eagle), pero rebajar los porcentajes a un nivel mas adecuado de Anti-squat sigue siendo complicado ya que habría que utilizar unos desarrollos bastante grandes (36T). Otro detalle interesante es que a pesar de la complejidad del sistema, la gráfica de Anti-squat tiene un perfil muy plano, algo que se podría haber conseguido con un sistema mucho mas sencillo. El Pedal-kickback (25º) como era de esperar es muy elevado, mientras que el Brake-squat (69%) se mantiene en un nivel medio, un buen dato si lo comparamos con otros sistemas de Pivote Virtual, aunque las diferencias son mínimas.
En la gráfica del Leverage Ratio vemos como el sistema es muy progresivo (3.15-2.2), unas cifras muy buenas para un modelo de Enduro. En cuanto al amortiguador la marca ofrece varias opciones (RSMP, FFX y FFX2) y en principio creo que el Fox Float X2 es una gran opción, pero lo mas importante es que el amortiguador tiene una medida completamente estandar (216x63mm) por lo que el propietario siempre va a tener la opción de montar otro amortiguador.
Un saludo.
18 comentarios:
Thanks for analyzing this; I was very curious to see how the 6-bar would come out. Not that different, I guess.
En RideMonkey el inventor del I-Track habló bastante bien del nuevo sistema de Weagle (sin entrar a analizarlo técnicamente, sino más bien en cuanto a sus posibilidades). Parece que en particular, en la Robot no se gastaron mucho en sacarle todo el partido posible, porque las características de la suspensión podrían haberse logrado con un sistema bastante más simple. Yo honestamente hubiera esperado una articulación trasera tipo Split Pivot, pero calculo que con el titanio no hubiera sido tan simple de ejecutar, así que aprovecharon que la patente del Horst expiró y le dieron para adelante.
Podian a ver creado un monopivote... y. y ya me puedo morir tranquilo, monozipote con ti y bicarbonio :P lo mas de lo mas :D jejejeje :)
SlimShady, there has been some discussion of this linkage already on another page on this site:
http://linkagedesign.blogspot.com.au/2013/06/instant-center-on-6-bars-tutorial.html
Antonio, things are more or less as you had expected. It looks pretty good, though. A flatter AS curve than a typical FSR with a bit of relief from kickback due to a decline in AS deeper into travel. Kickback seems in line with current classical DW-link which is not low but isn't too bad either. The AR curve improves on the DW-link. Whether more tinkering with this linkage will provide additional scope to further improve the AR curve, is unclear, at this stage, but the AR curve of the this bike as it stands is already good, although not as good as a classical FSR, perhaps.
Un saludo
Chris
http://www.pinkbike.com/news/first-ride-tantrum-missing-link.html hay que ver esto.
DJB2011,
The linkage is distantly related to the Felt Equilink and like that linkage it is a 6 bar Stephenson I link, I believe. I don't think there is any special significance that follows from the biasing link - Equilink on the Felt bikes and the short link sitting behind and just above the more elevated rearward mount of the shock on this bike - attaching to forward projecting sections of the lower and upper short links in the manner of a rocker. That is just one of many ways to govern the relative motion of the lower and upper short links using a third link that determines the bias/relative rate of rotation of the two mainframe mounted links thus connected.
I looked at the video explaining this linkage - see
https://www.youtube.com/watch?v=uh44UMTOmB0&feature=youtu.be
That is a weird experience. Brian, the guy doing the talking, disconnects linkage pivots in order to explain how the linkage works. But, that is an entirely invalid move, because the linkage can only work at all as a connected whole, that moves as one system, not as a series of free parts. Also, a claim is made that chain tension from pedalling can hold the linkage in a position that keeps the rear suspension in a fully extended state. First, that claim doesn't amount to much because for a bike with a properly adjusted SAG, there is no amount of chain tension (that can be generated by a rider) that can somehow lift the bike up and hold it there when its natural tendency on the contrary will be to return to SAG. Second, in the only imaginable circumstance where chain tension might produce the said effect - after the suspension fully extends due to a dip or leaving the ground - if chain tension holds the linkage and suspension in a fully extended state, that would be a very bad thing. Chain tension would be overriding the normal and correct behaviour of the suspension to return to SAG according to its natural and correct function with a stupid operational scenario of holding the bike in an extended state for no reason. As the claim is probably BS, in any case, perhaps, there is little reason to worry about this. Finally, not just the claim about the effects of chain tension but everything that Brian says is BS. He talks about a lot of forces that don't exist and fails to talk about the one that does - anti-squat. A normal analysis of this linkage and bike provided by the Linkage program will give the true picture of how this bike acts when pedalled.
Un saludo
Chris
Chris... prepare some popcorn, get confortable and open this link...
http://forums.mtbr.com/all-mountain/new-inovative-suspension-tantrum-cycles-any-thoughts-1009862.html
I tried, but it was impossible.
Best regards,
Tony.
Well, thankfully one guy there talked about suspension in rational terms - Vrock. I believe you may know him. Meanwhile, people over at Pinkbike were also reveling in the metaphysical powers of this linkage, so I took what I learned from Vrock and fed it back to them. I felt obliged the help, such was the delerium they were suffering. For my troubles I was inversely upvoted to -1 - my inverted popularity may have grown even more since the last time I checked. As I have achieved an inverted popularity from people living in an upside-down world, I figure I must be doing alright. I will wear my inverted popularity as a badge of pride.
Un saludo
Chris
Esta muy discutido el foro pero igual me gustaria ver el funcionamiento.
Jajaja, realmente imposible. No lo había visto hasta ahora, pero no pude resistirme a ver como era con el Linkage y me llevé un chasco después de leer la prueba de Pinkbike. Por ejemplo las Scott (hasta ahora al menos) tienen un LR regresivo y lo he podido probar y he comprobado que no es un funcionamiento óptimo, se cumplía la teoría de forma clara.
Además muchas cosas de las que comenta en su web no parece que se cumplan, no se si por marketing o errores suyos (cosa que dudo, espero).
Lo de la relación entre el LR y el amortigudor, en fin... y lo que comenta Chris del vídeo ya me ha parecido increíble, no tiene ningún sentido mover cada bieleta por separado porque el funcionamiento de todo el conjunto es totalmente diferente. He is comparing apples and oranges ;P
Que opinión te merecen las nuevas Unno? A mi la de DH me ha dejado un poco frío (sin estar nada mal ojo), quizás tenía unas expectativas demasiado altas :S
Otra cosa, tengo la idea de que un anti-squat plano alrededor del 100% o ligeramente creciente es lo ideal para pedalear, especialmente de pie ejerciendo fuerza. Y acompañado de un LR bajo y no demasiado progresivo al inicio, tipo yeti o alguna de DW. Estoy en lo cierto? Pienso que quedaría una suspensión eficaz pero no incómoda y con un buen funcionamiento para bajar a tope, con buen tramo medio y recorrido aprovechable fácilmente (enfocado al enduro jeje).
Un saludo a todos!
Antonio,
Crazy as it seems I appear to be in a debate with Brian Berthold over at Pinkbike.
http://www.pinkbike.com/news/first-ride-tantrum-missing-link.html
The user "stillunimpressed" would be me. Actually, I'm seriously out of my depth and the whole thing is pretty amusing, although not obviously funny. I'm sort of paddling around in the shallow conceptual waters that I am comfortable with but there are many things I am clueless about, and it probably shows.
I would be grateful if you take a look at what I have been saying and point out any gross errors. I'm sure there must be some not least of which my points are mainly qualitative and obviously not quantitative. I could very well understand if you chose to decline.
I'm more or less done with debating the fellow. There are some elementary definitional matters that he rejects, even after invitations to reconsider and when there is nothing at stake. I don't get it and will be cutting my losses. Still, I would prefer some considered criticism from you, that perhaps can guide me to neither grant too much or concede too little to Mr. Berthold.
Others may like to consult the debate as either light entertainment or gentle self-flagellation.
Cheers
Chris
This man is Tony Ellsworth 2.0
It is impossible to argue with him because he really believes in all the crap he says... He thinks he is right and the rest of the world is wrong. The part when he talks about 6 bars for example, a Knolly is a 6-bar, but I can accept someone calling it a 4+2 system. Same Axle path as a 4-Bar, and two extra links that only change the shock rate...
But his system is definetely a 6-Bar. If you move the position of any of the pivots, the Axle path changes, so it's a 6-bar. I can't believe he is calling it 5-Bar.
And BTW I just saw Anopura's comment. LOL.
Best regards,
Tony.
What remains weirdly remarkable about the bike is the way it can apparently hoist itself up, raising up the chassis on the rear suspension linkage to final top out of the shock, as if the bike climbs its own aggressive pre-SAG AS curve. Excuse the intermingling of physical description and poetic images but describing what happens isn't so easy. And somehow that aggressive LR curve manages to consume the suspension extension as it is occurring putting it away as a ride height bank by sucking it all in and, by that means, spontaneously altering the SAG point, i.e. reducing apparent SAG/increasing ride height.
I had heard about this kind of AS curve being discussed in motorcycling circles as a traction destroying, compliance compromising and stability upsetting mistake that never should be made. I never expected to see such a thing in the bicycle world.
Mr. Berthold will have to prove why what is anathema to the motorcycling world should be considered just what the doctor ordered for mountain bikes.
Un saludo
Chris
Las dos ventajas principales de la impresión 3D es la personalización y el poder usar tubos de fibra de carbono evitando los moldes, que en principio rebaja los costes de construcción de un cuadro. Si no consiguen rebajar el precio, la personalización de la geometría por sí sola únicamente va a alcanzar un sector del mercado muy reducido. Un público selecto, eso sí, esto no es para las masas.
I've left a reply in pinkbike. What a discussion Chris! haha
I do not know if this man is wrong or what happens. Also in one of the videos you can see how the shock bottoms out quite easy when try to climb a hill. I think this is a proof of the regressive and high LR.
Un saludo
I thank you for that MrBlackmore. Today, you are a hero to me.
Friendly regards
Chris
I came across several references to a new suspension system DW has been working on called ORION. It is a 4 bar that can be easily adapted for use in MX motorcycles - the highly compact ORION dual short link linkage can easily be mistaken for a normal single pivot so inconspicuous is the linkage hardware.
ORION appears to be closely related to the linkage on the R160. The compact 4 bar assembly immediately above and behind the BB on the R160 is very reminiscent of and no doubt was inspired by the ORION linkage. The major difference is that ORION doesn't employ a seatstay or upper rocker link - the normal looking (but actually novel) ORION swingarm floats on mounts attaching to two short links (just like the rigid rear triangle of a dual short link mountain bike) without any direct connection to the main frame. Put another way, if you eliminate the seatstay and upper rocker on the R160 and extend the lower suspension arm/chainstay/swingarm all the way back (without any intermediate pivots) to the rear wheel axle as the carrier structure for the wheel and axle then you would indeed have a version of ORION. That kind of setup would be impractical on an MTB, of course, but with suitable modifications ORION could be used to great advantage on MTBs.
The benefits of such a linkage would be i) the ability to achieve a relatively flat AS curve in ii) an extremely compact package that iii) is mechanically simple and iv) strong and v) light, while remaining vi) versatile with application for conventional suspension bikes as well as high pivots and motorcycles. Also, as the R160 demonstrates ORION's versatility extends to the ability to mix and match with other design approaches to achieve novel results.
The recent appearance of the extremely interesting i-Track based Craftworks ENR underlines the growing need for linkage designs that can be readily adapted to bikes of that sort. The suspension linkage of the ENR is well designed but I have a strong suspicion that an optimised form of ORION for this kind of application (including the floating idler cog characteristic of the i-Track design) would be even better.
Un saludo
Chris
If you eliminate the rocker link you can't manipulate as well the LR and that's something very important if the bike has an air shock. I guess the Ibis Ripley is the closest thing that we are going to see to the Orion System and it works pretty well, but times goes by and it's still the only one of it's kind, DW haven't used it for any other bike with a bit more travel.
Best regards,
Tony.
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