En esta entrada voy a analizar a la nueva Foes Trail Mixer 2016, un modelo realizado en colaboración con el distribuidor Timberline Cycles, que fue el que tuvo la idea de crear una version de la Foes F275 con una rueda delantera de 29''. El sistema sigue siendo el clásico Monopivote con Bieletas de Foes con un recorrido ajustable de 140mm-152mm, aunque en este caso hay que tener en cuenta la llegada de los nuevos amortiguadores Fox Float EVOL...
Como podéis ver en la tabla de excel y en las gráficas anteriores el sistema de la nueva Foes Trail Mixer tiene una Eficacia de Pedaleo bastante alta. El sistema está optimizado en torno a una transmisión tipo 1x11 con un plato de 28T-30T por lo que se puede decir que está muy bien ajustada. Al ser un sistema tipo Monopivote es preferible quedarse un poco corto antes que pasarse con los porcentajes de Anti-squat. De esta manera se consigue que el Pedal-kickback (18º) y el Brake-squat (89%) se mantengan en un nivel alto, pero que no llega a ser excesivo.
En la gráfica del LR vemos como el sistema es del tipo Regresivo-Progresivo-Regresivo (2.3-2.4-2.05-2.1), pero los tramos al principio y al final del recorrido son muy pequeños por lo que podemos simplificar un poco y decir que el sistema tiene una progresividad bastante suave (2.4~2.1) y un LRM muy bajo gracias al amortiguador de 216x63mm. La bieleta ofrece dos posibilidades de anclaje para el amortiguador, pero tanto la geometría como la horquilla de 140mm dejan bastante claro que la posición mas lógica es la de 140mm. En cuanto al amortiguador este modelo viene equipado con un Fox Float DPS con cámara EVOL y creo que es una decisión acertada, sobre todo desde un enfoque tipo Trail-AM, ya que la cámara EVOL se adapta muy bien a este tipo de LR y con 140mm de recorrido "no es ogligatorio" montar un Fox Float X...
Un saludo.
14 comentarios:
Foes has stuck to the 'low leverage ratio' concept in suspension design like nobody else. I am curious to ride a bike of this sort. Those forces curves seem very good. If I am reading things correctly, those curves would translate to a firm ride with moderate escalation. Indeed the forces curves, notwithstanding that firmness by design, do not suggest the suspension lacks compliance - there are many bikes without such low leverage ratios that have steeper gradient curves that clearly would be less compliant in the last quarter of travel.
Just about all decent suspension bikes seem to aim for a target zone of 6 - 10 N/mm at SAG. That governs the responsiveness of the suspension. The Mixer is at the upper end of that range. I wonder whether that might make the Mixer a bit too firm at the SAG point.
Un saludo
Chris
Gradient curves depends too much in which shocks is the bike using and if you mix old and new bikes in the same graph you get huge differences... In this one the Foes has a 216x63 EVOL, the Canfield has a standar 200x57, SC Hightower 200x51 EVOL and Nicolai a standar 216x63.
The Foes looks firmer around sag compared to the others, but if you use a similar shock in all of them, gradient curves will be a lot closer...
Best Regards,
Tony.
Antonio, allowing the selection of shock is a major factor, do you still have an opinion about whether there are benefits for suspension performance by favouring either the lower or higher ends of that 6 - 10 N/mm band at SAG?
Cheers
Chris
I know why some people like to have a lot o support (Jumps, berms, etc...), but it would be interesting to do a WM experiment and see what really happens when there are a lot rocks in the middle of the trail... Right now I'm doing an experiment with oval rings and maybe when I finish that I can check what happens with all these new shocks.
Best regards,
Tony.
Great!
Hola Antonio.
Aprovechando esta entrada...te pregunto algo que llevo dando vueltas mucho tiempo. Estoy pensando comprar un cuadro de 27,5" y montarle delante horquilla y rueda de 29". Estaba entre dos, el Fireeye Burning y el Conway WME, sobre todo por el precio y porque creo que son dos buenos cuadros(llegando a esa conclusión por tus análisis). La idea es montar delante una 36 talas de 160 que ya tengo. Tiene un rake de 51mm. ¿Que te parece la idea?. ¿Cuál te parece mas apta?.
Gracias!!
Ninguna de las dos, a un cuadro de 27.5" no le puedes poner una rueda de 29" y mucho menos con una horquilla con tantisimo recorrido porque vas a destrozar la geometría. Lo que si podrías hacer es montar una rueda tipo 27.5" Plus. Si lo que buscas es seguridad en la rueda delantera puede que te de buen resultado y en unas malas puedes volver a una rueda normal y la horquilla sigue valiendote...
Un saludo.
La verdad que pensaba que no era para tanto el cambio de geometría. Gracias por ponerme en mi sitio, je je. Veo buena idea lo de la 27,5" Plus. Te refieres a solo delante o detrás también?.
Un saludo.
Yo también tenía la duda de Millabike, en este caso para la Capra. Pensaba que si tienen una versión de 27'5 con horquilla de 180 mm, se podría meter una rueda 29" con horquilla de 160 mm sin afectar la geometría apenas. O hay algo que se me escapa?
Una rueda de 29" levanta la dirección unos 3-4 centimetros en comparación con una rueda de 27.5" y para mi eso es demasiado. Poner una horqilla de 180mm en vez de una de 170mm es algo mucho mas simple y no afecta casi nada...
Un saludo.
It is normal for MX motorcycles to have mismatched wheel rim sizes - 19in in the rear and 21in in the front, commonly - but that does not usually mean that the overall tread to tread diameter of the tyres varies much. To give a sense of proportion a Maxxis MAXXCROSS MX IT front tyre (80/100-21) is 27.8in in diameter whereas the rear tyre (110/90-19) is 27.6in in diameter. I suspect that there are probably good reasons for the close match between tyre diameters. The Mixer, however, has mismatched tyre diameters and that probably isn't a good idea.
Perhaps, a 29in at the front and 27.5+ at the rear would make more sense, assuming the latter can be accommodated on the bike. But, there is really more at stake than just getting a rough match between front and rear tyre sizes. Are mountain bike tyres as currently constructed as good as they could or should be? A 650B wheel rim is 584mm in diameter (23in approximately) and a 29er wheel rim is 622mm in diameter (24.5in). Common mountain bike tyre profiles, i.e. tyre width relative to sidewall height, seems in line with MX tyres. MX tyres divide up the tyre surface differently, though - there is a lot more noticeable tread curling around onto the sidewall and the tread free part of the sidewall is a relatively thin strip. If normal (and admittedly heavier) MX tyre construction is anything to go by, there is a lot of scope for improvement in mountain bike tyres.
Interestingly, the MX world has experienced fads, quite similar to the 'plus' tyre fad. Some time back, there were those who had announced the death of the "thin", "low air volume" tyre supported by the old style 21in front rim in favour of a newer, "wider", "high air volume" tyre, that would be mounted on a 20in rim. Guess what, the fad failed - the announcement of the death of the 21in rim was bogus! No one could win races with those supposedly advanced tyres. The problem is that you can't just add vast amounts of sidewall without introducing scenarios in which traction will be diminished as a result of the complexities of tyre design. The mantra of wider tyres may well be sound but you will typically want those wide tyres to be implemented in low profiles, without substantially increasing the surface area of the sidewall, if you want to experience the full benefits that those wider tyres can offer. If reason was governing events, there would be no need to go to larger 'plus' tyres (or smaller rims) to get the additional tyre width that riders have begun to demand. A standard diameter tyre could be made in a wider/lower profile casing that is designed to mount on wider, but otherwise normal, rims.
Un saludo
Chris
Buenos días Antonio.
Sería posible que analizases la Foes Mixer Enduro?
Gracias.
http://foesracing.com/bikes/frames/foes-mixer-enduro/
Antonio,
Could you tell me what default value you use for rider weight (and bike weight, too, if you happen use that as well) in your forces calculations. And, for steel and titanium springs do you use a default spring rate or not?
Thanks in advance
Chris
In Response to Chris's comment,
As history now shows, mixed wheel designs are the next step in mountain bike design and decidedly not just longer, slacker, more complex linkage designs.
The advantages of the "Mullet" design now championed by Mullet Cycles which is the brand successor to Mike Vidovich's (formerly the operator of Timberline Cycles) are manifold. Offset axle heights decrease rollover resistance in addition to the difference inherent to 29" wheels versus 27.5" expressed as attack angle. The differences in scrub ratios and rotational momentum between the two wheel sizes allow for greater stability in cornering as well as ease of initiating the turn. Mike spent years developing the Foe's Mixer and now the Mullet Cycles designs that he now sells. The answer to the dedicated mixed wheel geometry question is not slacker head tube angles as current trends follow. The stop gap measure of "flip chip" adjustment is completely insufficient to adapt symmetrical geometry to asymmetrical wheels. A dedicated mixed wheel geometry has far too many benefits to merit reverting to the primitive road bike on knobby wagon wheels that currently predominate due to hold overs from previous UCI rules.
Mike V is an avid moto rider and former Gas Gas dealer at Timberline. He is a certified suspension technician and the Peacemaker model from Mullet Cycles will feature his own single pivot design with custom tuned shock options. The Single pivot URT design minimizes excess linkage arms and maximizes torsional rigidity. Radial and needle bearings both make up the pivot position.
Moto design might indicate to the uninitiated that rim differences are immaterial to performance due to effective tire wheel diameter. Larger rear tires prevent rear flats and are accommodated by smaller rear rims. Moto tires are described in terms of aspect ratio which MTB is sure to follow as larger tire widths are much more useful in the mixed wheel as opposed to symmetrical wheel configuration. The 1/4th horse power produced by a human cyclist is what accounts for the wheel diameter difference as opposed to the torque forces capable of a motor driven cycle. Rear tires are compressed more readily when motor level torque is applied.
Linkage designs in mountain bike rear suspension are not necessary due to the developments in rear shocks and their tuneability.
I look forward to Antonio analyzing the Mullet Cycles Peacemaker when it is released as it is the proper successor to the Foes Mixer which is only now adopting changes that Mike suggested years prior to 2020. Nevertheless the Peacemaker will outstrip the entire industry Foes included.
Respectfully,
Ben Schild
Idaho Falls, ID
United States
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