Lo mejor del año 2012

El año que acaba de terminar es uno de los mas fáciles de resumir desde que empecé a escribir el Blog, por un lado tenemos a las ruedas de 29'' dominando totalmente el segmento XC, aunque a estas alturas ya prácticamente no es noticia. Por otro lado tenemos a las bicis de DH, que poco a poco se van pasando al carbono, aunque casi ninguna ha aprovechado para renovar sistema, y por último tenemos una autentica revolución en el mundo del Enduro, con la llegada totalmente inesperada de los modelos de 27.5''. 


La ruedas de 27.5'' llevaban ya cuatro años años en el mercado, pero nadie les hacía ni caso, solo había un par de modelos de llantas y cubiertas (Pacenti) y casi ningun fabricante tenía modelos específicos para esta medida (Ventana, Jamis y poco mas...). Este año de repente todo el mundo ha sacado un modelo de Enduro de 27.5'' y hay muchisima mas variedad de llantas, cubiertas y hoquillas de suspensión. El año que viene creo que puede ser muy similar, sobre todo en modelos de Enduro, aunque a partir de ahí no tengo ni idea de lo que puede pasar, es casi imposible predecir que va a pasar con los modelos de DH o con las Trailbikes, que quedan justo en la frontera entre las 29'' y las 27.5''.

Un saludo.

27 comentarios:

Chris dijo...

I'll venture an opinion on wheel size. Of course Gary Fisher was right that larger wheels will roll over obstacles and through dips better. The amount this simple proposition was disputed indicates just how habituated to dubious received wisdoms a sport can become.

But rightly viewed this simple truth about the relative size of wheels does not prove the superiority of 29in wheels in general. Why not 32in wheels, say? Surely, they would roll over obstacles and through dips better (allowing that there must be engineering answers to the engineering problems introduced by the big wheels). The simple answer is that rolling over stuff is not the only thing that matters when we look at what the bike is meant to achieve and that anyway we have other ways of improving the ability of a bike to roll over stuff - um, suspension!

It is already clear that the current crop of 29ers aren't for everyone. An awful lot of engineering effort (and a new very short headset standard, I believe) would be necessary before misgivings of small riders about 29ers could be allayed.

More importantly, for those of us mainly concerned with suspension bikes, it is simply harder to get a good balance between the main variables governing the ride and handling of a bicycle when using larger wheels - wheel path and anti-squat. This is not too noticable on short travel 29ers but wheel path of a long travel 29er (if anyone bothers to build such a thing) would be far from ideal - the rear-centre length would reduce quite a lot as the bike moves further into its travel.

A lot of the comparisons we have seen between 26in and 29in bikes so far have been rather slap dash - little attempt has been made to control the variables (tyre widths and treads for example) that must be controlled in order for these comparisons to be meaningful. I'd like to propose a couple of 'yardsticks' that could better allow for meaningful comparisons between suspension bikes with different sized wheels. First, stack height. Recently, a strange habit has arisen of comparing 120mm 29ers with 140mm 26in bikes. Why is that a meaningful comparison? I don't think there is a sensible answer to that question. If we take stack height as a yardstick however a 120mm 29er should be more properly compared to a 26in bike with around 160mm travel. Stack height is the best criterion for corrected sizing across bikes with different sized wheels.

The other yardstick would be average speed to power ratio. The idea is which bikes return more forward motion for the input from the rider. It is not hard to imagine that different bikes might perform better in different circumstances, downhill, uphill or over rough terrain. This could all be done against the stopwatch with the assistance of that modern convenience the power meter.

I am a medium size rider who wants one (full suspension) bike to do it all. I do not feel drawn toward 29in wheels. They are for a rider with different interests i.e. an XC orientation. I am very interested in whether 650B / 27.5in wheels will be beneficial for a rider like me. I am hopeful but not yet certain that this will be the case.

Un saludo

Antonio Osuna dijo...

Gary Fisher developed 29er bikes in the late 90s, take a look at any catalog of that era and you'll see how bad FS bikes where around that time. They were really bad, had very little travel, Fox didn't had PP yet, Virtual Pivots didn't even exist, URT were still around...

So GF did all the tests using hartail prototypes. He didn't try to build a 160mm Enduro frame with those wheels and see how it works, he was a genius but he probably had no idea FS would go that far.

27.5 wheels make everything so much easier to design, and work well, so they are here to stay.

Best regards,
Tony.

Josep Barberà dijo...

Chris, Antonio... voy a ser más explicito/concreto/vehemente, en mi opinión.

Las ruedas de 27.5" van a sustituir a las de 26" des de ya!.
Durante un tiempo (hasta su desaparicion), esas rueda pequeñas, se repartirá entre la gama baja de cada marca.

Y me detengo en un detalle importante: ha habido dos marcas importantes y muy conocidas (Giant y Specialized), que han perdido una oportunidad magnífica de dar este año el paso hacia este nuevo estandar de rueda.

Espero, que el año próximo reaccionen a lo grande, y ofrezcan al consumidor un producto en 27,5" maduro y contrastado, sobretodo en su gama enduro. Nicho natural para este diámetro.

Un saludo.

José Conca dijo...

Lo que no me convence de la 27,5 es que no está a mitad camino entre la 26 y la 29 como muchos quieren hacer creer. Está mucho más cerca de la 26 por lo que no aporta demasiado, apenas 3 cm más de circunferencia creo recordar. Habría sido mucho más acertado ponerse los fabricantes de acuerdo y estandarizar una rueda verdaderamente a mitad de camino entre las 2 medidas que ya hay.

Antonio Osuna dijo...

O algo incluso mas cerca de las 29' que de las 26'... pero eso es un poco ciencia ficción, los fabricantes nunca se van a poner de acuerdo en algo así, cada uno se busca la vida como puede, y Pacenti apostó por esta medida posiblemente porque era compatible con muchas horquillas y algunos cuadros, Un poco mas grande y la rueda no entra en ningun cuadro ni horquilla de 26'........

Un saludo.

Chris dijo...

The point of my statements above was to question the one-sided preoccupation with large wheels without regard for other dimensions of bike design and geometry. There is such a thing as too much of a good thing in my view.

A very amusing video has appeared on the web - http://www.youtube.com/watch?v=fYt6IqaHk_Q - made by someone who wouldn't likely be impressed by my reasoning. The fellow rides his rigid 36er (yes, that's 36in wheels) up a long set of stairs snaking up a hill. Whatever, else one may think of this, it is proof of the prowess of larger wheels in rolling over obstacles. This guy climbs the steps as if they weren't there.

A video I was less impressed with that also sings the praises of larger wheels - see http://www.bikeradar.com/news/article/video-29er-mountain-bikes-traction-33324/ - makes the claim that 29ers are better climbers (up rough steep climbs). The basis of this superiority is supposedly better "traction" and more "usable torque". I find the argument by the Bike Radar proponent unconvincing as it stands. Still, good traction of 29ers has been widely reported and when you combine this with the undeniable fact that they roll over stuff with less fuss than smaller wheeled bikes (look at that 36er video again if you aren't convinced) one has to acknowledge the proponents of 29ers may indeed be on to something where climbing is concerned. (Also, I wonder whether there is something about 'natural' body positioning and pedal leverage on a 29er that might also contribute to the smooth clean climbs we witness in the video - a speculation only.)

Any thoughts Antonio?

Cheers
Chris

Antonio Osuna dijo...

Well, a 36'' it's obviously too big, but 29'' are not that bad. If you work hard you can design a frame with good geometry (Short CS,etc...), and if you spend a ton of money you can buy carbon wheels and make it very light so it will climb really nice.

27.5'' it's going to work very well with AM bikes, and it's going to be very affordable. 29'' it's probably better, but only on the most expensive models.

Best Regards,
Tony.

Anónimo dijo...

Yo creo que para rally marathon la superioridad 29 es indiscutible...para todo uso vaticino una ola de ruedas de 27,5 en cuadros de 26...esto solo acaba de comenzar y hay una crisis de miedo...cambiar una bici que tienes bien montada es una locura pero nadie quiere renunciar a lo mas nuevo.saludos.
grande46

Josep Barberà dijo...

De acuerdo Anónimo a medias... Lo de 29" parece que si.

Lo de montar ruedas de 27.5 en bicis no preparadas para esto, es una tonteria.
Toda la geometria se va al carajo, sobre toto lo más importante en una bici "todo uso" como comentas.
El eje de pedalier sube una barbaridad, lo que provoca que la bici sea ingobernable a alta velocidad, por el aumento del CDG del conjunto.
Eso suponiendo que las ruedas entren, y suponiendo que entrando, no te metas en ningun barrizal... de ahí no se sale!.
La gente que leemos estos blogs, no podemos aceptar que comprando una bici estudiada y diseñada por el fabricante para funcionar con ruedas pequeñas... les metamos sin más y por que entran y es la moda, unas ruedas mayores.

Un saludo.

Unknown dijo...

I was looking at some bicycle geometry charts (on the Orbea and Specialized sites) and it has become apparent that 29er XC suspension bikes (e.g. Occam 29er) in their sagged riding position do try to replicate a certain relationship between CoM, BB and rear axle positions (in the vertical plane and relative to one another) that is the norm for a modern race oriented road bikes - about 70mm BB drop.

This supports (but by no means confirms) the proposition that 29ers, besides any benefits that derive directly from the wheel size, are also focused on efficient power transfer, just like road bikes. It also makes the claim that 29ers are good bikes for climbing kind of plausible. The climbing advantage (if there actually is one) would perhaps derive from sources other than those often credited (i.e. "traction") though. The 29er could just be more efficient at getting power to the ground i.e. it is, in a climbing context, primarily a less power limited machine, when compared to a 26in bike, rather than a less traction limited one (although that might be true too).

This is speculation but I would be keen to hear what the engineers amongst you think.

None of this alters certain disadvantages of 29ers - higher CoM, excessive chainstay length and stack height.

Cheers
Chris

Josep Barberà dijo...

Bueno Chris, lo de la teoria de que las 29", tienen unas vainas demasiado largas... queda en entredicho con la nueva propuesta de Specialized en su Enduro.
Supongo sabrás, que las vainas de esa bici, miden 43 mm.
Medida totalmente normal para una bici de 26"!!

Un saludo.

Unknown dijo...

Thanks for pointing that out Josep (and also to Antonio who made an oblique reference along these lines earlier). Specialized and Devinci deserve a lot of credit for overcoming the 29er chainstay length issue.

Do, I think this makes 29ers suitable for long travel purposes? No. The Enduro 29er will sag to about 300mm BB height in use. That translates to about 70mm BB drop. This means the rear axle will be as high or higher than the main pivot and that axle path will principally arc in towards the seat tube rather than moving rearward away from the bike (please note, this does not mean that chain growth won't occur although it be somewhat less than commonly occurs). That is not my idea of a good axle path for a mid or long travel bike. The 29in wheel will calm things down of course but can't really paper over the geometry compromise.

So, my own view is the 26in Enduro is still the better choice and that 29in wheels are more appropriate for XC than other purposes. (That may not hold for unconventional bike designs.)

Un saludo

Unknown dijo...

I think I have been too hasty with some of my comments. The shortcomings of Specialized's 29er FSR rear suspension implementation are not necessarily shared by others.

NORCO, I think, are on the right track by moving the swingarm link pivot forward and downward on larger wheeled bikes, thus preserving the rearward wheel path to an extent. Similarly, properly configured, a Santa Cruz like VPP linkage could trace a more rearward wheel path, although the current Tallboy isn't a good example of this.

Un saludo
Chris

Antonio Osuna dijo...

Chris, I think that the BB height of the Occam and the Epic is pretty standard: around 330mm. The idea of a low BB it's to improve the way the bike corners, I don't think it has anything to do with power transfer.

Axle path is a little bit worse, but bigger wheels compensate for that easily.

Best regards,
Tony.

Josep Barberà dijo...

Muy interesante.
Entonces Chris, insinuas que en las bicis de ruedas grandes, no está bien resuelto el tema de la treyectoria de la rueda trasera, durante el recorrido?.
Me parece entender, que en lugar de seguir una trayectoria más o menos vertical... lo que hace es encoger la longitud total de la bici acercando la rueda trasera en demasia hacia el interior del cuadro?.

Puede suponer este aspecto, un ralentizamiento de la bici durante los momentos de máxima compresión del amortiguador?.

Un saludo.

Unknown dijo...

Scorecard of most current mid travel 29ers: Big wheels - great! 70mm BB drop (riding) - great! Wheel path - oops! Two out of three doesn't do it for me.

If someone was to build some sort of Zerode-like AM bike with big wheels and plenty of travel I would start saving my pennies. Until then I will be giving 29ers a miss.

Un saludo
Chris

Unknown dijo...

Lo que se dice más arriba de la trayectoria de la rueda en una bici de 29 a la hora de absorber obstáculos no me parece ninguna tontería. Esto se solucionaría mezclando 29 delante y 27.5/26 detrás. ¿Tu que opinas?
Ignacio

Josep Barberà dijo...

Bueno Ignacio, como supongo lanzas la pregunta a todos, y no solo a Antonio, respondo.

Hace muuuuucho tiempo que he dicho en este blog, y en otros sitios, por qué no bicis con ruedas de diferentes diámetros?.

A mi me encantaria por ejemplo (y por talla personal), bicis de enduro con cuadros adaptados a 27.5" delante y 26" detras.

Es más, cuando las marcas nos hayan vendido suficientes bicis de 27,5" y 29" en los dos trenes, entonces empezaran a sacar mixtos como los que tu y yo decimos.

Al tiempo!!.

Un saludo.

Unknown dijo...

Efectivamente es para todos.
Yo he llevado algún tiempo una rueda de 29 delante y me gustaba pero el pedalier me quedaba un poco alto y la horqilla algo lanzada. Supongo que con alguna Banshee se podría solventar el cambio de geometría cambiando la puntera.

Ignacio

Unknown dijo...

Ignacio, Josep,

I think you are right, slightly mismatched wheels, 29/27.5 or 27.5/26 front/rear, could work. My impression is most designers are quite cold on the idea, but I can't say why.

Un saludo
Chris

Unknown dijo...

I just did some sifting through the information collected on this website and the public library of suspension linkages accessible via the Linkage program. I was wondering about whether there were any linkages that managed to produce something like a 'classic' wheelpath for a 29er with some chainstay lengthening after SAG. The rationale is simple, if you can get something approximating the classic wheelpath why not prefer that over the alternative of a shortening chainstay (horizontally after SAG) which is more commonly implemented on 29ers today? Surely the latter results in a suboptimal wheelpath.

Note:
1. My comments have nothing to do with the issue of chaingrowth.
2. High pivot designs with diverted chainlines are not considered.
3. Some well known multilink designs are not mentioned because I have no information on how they might be implemented on a 29er.
4. My comments are based mostly on real bike linkages. Where necessary, I have done a bit of creative variation on known linkages to see if anything noteworthy pops up.

It is apparent that some linkages do a better job of reproducing (a subdued version of) the classic wheelpath than others. All 29er single pivots and horst-links in the Specialized FSR style have the suboptimal shortening chainstay. Santa Cruz VPP (Blur, V10 style, etc.) likewise. Giant Maestro, the Banshee linkage, Marin Quadlink 3 all follow a similar pattern.

Bikes/linkages producing a closer to classic wheelpath included: DW-link (that was a big surprise, but DW does implement his 29er linkage somewhat differently to the normal 26in implementation), horst-link as found on the new NORCO 650B bikes and the VPP linkage found on the Antidote Lifeline bikes. The references to the NORCO and Antidote linkages are only justified as creative exploration to answer the question of whether horst-links and VPP style linkages can produce a classical wheelpath for a 29er. Those 29ers don't actually exist, but can be easily implemented with good results. The Yeti SB95 linkage also has a similar wheelpath to these bikes but might result in more pedal feedback than the others if the results I have observed in Linkage are sound.

It should be pretty obvious which 29ers I think are better.

Un saludo
Chris

Antonio Osuna dijo...

Well, if you want a rearward axle path on a 29er you have 3 options:

1. High Pivot + Idler. It's not impossible, XX1 make it an option for XC frames.

2. Floating Bottom Braket. But it has pros and cons as you know...

3. Medium High Pivot, or Virtual Pivot, but you get a lot of Pedal Kickback. XX1 helps a lot here too.

Best regards,
Tony.

Unknown dijo...

Yes that's pretty much what I'd like to see I suppose (I know you doubt the wisdom of this, Antonio). I can't think of any 29ers in the first two categories - I imagine there are some. I am not too clear on which design you are calling a "Medium High Pivot" - a Commencal Meta AM 29 or a Scott Gambler perhaps. The Commencal has very little chainstay extension / rearward path. A Gambler-like 29er would be better in this respect.

Most of the available 29ers that fall into the categories you mention are Virtual Pivots. For the most part, these too fail to have rearward paths. Actually, I made too much out of the very slight differences between the DW-link and Yeti Switch and the other mentioned linkages, they are more similar as a group than they are different.

Only the two synthetic creations I mentioned (Antidote Lifeline 29er and NORCO Range 29er) which were nothing more than mental experiments had a significantly more rearward path then the others at a bit less than 50% of the horizontal chainstay extension of similarly designed 26in bikes. The method used to create these bikes was in line with the common method we see at large today - maintain the relative positioning of pivots and BB to the extent possible and also the position of BB relative to the ground. Allow the necessary changes in the relative positioning of BB and rear axle so that at SAG BB drop is 65mm - 70mm. Interestingly, despite the more rearward axle paths these bikes did not show notably poor pedal feedback numbers in Linkage.

So, as you say, a more rearward axle path could be implemented in a number of ways. My point is this is not actually happening. We are getting second class 29ers rather than the real deal.

Un saludo
Chris

Antonio Osuna dijo...

Not so long ago, you could hear a lot of people talking about how good the big wheels were, so good that you didn't need a Full suspension at all.

You can't go from that to having the best suspension designs in the MTB world. It takes time to figure it out.

Best Regards,
Tony.

Unknown dijo...

Almost a year has passed since Antonio made this post and some of us offered our opinions.

At the start of 2013 a shift to 27.5/650B was on the cards but it has been dramatic. Interestingly, 27.5in geometry has gone from a small presence to complete domination of the mid-travel MTB sphere. In the robust process of establishing a 27.5in presence, several lines of demarcation have been drawn between 27.5in and 29in bikes which mean that the latter will remain on the shorter travel "XC" side of the divide and/or will represent a bike sizing option that has strong appeal for taller riders.

Most manufacturers (except Specialized and some specialist builders) acknowledge the travel based demarcation principle directly - it is rare indeed for a manufacturer to release a 29er with more than 140mm travel. The bike sizing based demarcation line is less universally acknowledged but is obvious in the approach being followed by ORBEA in the way it markets its hardtails. Small sizes are available only in 27.5in. Medium are available in both 27.5in and 29in. Larger sizes are available only in 29in. Will this spread to suspension bikes? I would imagine it will. None of this has been entirely settled yet although "the die has been cast" and things are really just being worked through at this point.

So, there has been a dramatic change (I hesitate to say a revolution) and it has happened very quickly. I think it is clear that the star of 26in geometry for (mainstream) MTBs has waned. Short and mid travel 26in MTBs will disappear in time. (This does not mean that 26in is bad - the bike I most covet is the 26in Kross Moon - but rather that it is shortly to be superseded.) No one was hurt by this change and there are some very appealing bikes out there as a result - the glass is still half full.

But what is happening in the DH sphere? Well, the expected showdown between 27.5in and 26in didn't occur in 2013. Personally, despite being quite at home with the changes in the XC and Trail/AM/Enduro spheres I would be happy if this slow (cautious?) approach was to continue for DH. Certainly, it is good to see the manufacturers testing rather than foisting some ill considered change onto riders. There also seems to be a lot of basic questions about the direction that change could/should take for DH bikes. Asking and answering these questions will take time. Do we want bigger (650B) wheels or do we want more travel, say? Okay, I have just invented a reason not to favour bigger wheels - no fork manufacturers are currently proposing this. Still, basic design decisions need a certain breadth of vision and should not be rushed. And, increasing wheel size does tend to narrow the option to increase travel. Worth thinking about.

Lastly, a question that has been bothering me lately is what should we make of the quoted "fork travel" values issued by fork manufacturers. Clearly, fork stroke (i.e. the distance the slider moves along the fork stanchions) and vertical travel are not the same and should not be confused. Antonio, maybe you could set me straight on this.

Un saludo
Chris

Unknown dijo...

I should mention, that Liteville, as always, is going its own way on wheel size. Their bikes will accommodate any wheel sizes between 24in and 29in and specific configurations, including configurations using mismatched wheel sizes where the front wheel is slightly larger, will be offered/recommended based on the physical attributes of the rider alone without regard to suspension travel. (I am not sure whether this applies to all of their bikes or just the 301 but up to 160mm travel, at least, it appears that 29er wheels are considered to be nothing more than an aspect of bike sizing.)

Liteville has a unique vision and while I am no more convinced today than I was a year ago about the ultimate wisdom of long travel 29ers, I am nonetheless impressed by the straightforward way that Liteville makes it case - it is a sizing option that benefits taller riders.

Un saludo
Chris

Antonio Osuna dijo...

In a couple of months I'll be writing the "Best of 2013" article and I'm pretty sure it's going to be about wheels too.

IMHO there are three ways to divide 29Ers and 27Ers: Size, Travel and Cost. If money is not a problem you can build a sweet 29er. Carbon wheels are superlight and very strong, they cost a fortune too and that's the main problem...

Best regards,
Tony.

 

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