Specialized
just released the 2018 Epic, a 100mm-travel all-out cross-country race bike, so it was no surprise to see Kate Courtney aboard the new machine in Andorra, shot here by Pinkbike race photographer Irmo Keizer. Gone is the FSR design, with the rear axle pivots now replaced by a flex-stay system that's said to shave 240-grams on its own, or a weight saving of approximately 39% over the previous model. The top drawer S-Works frame is claimed to be a whopping 345-grams lighter than the 2017 version, with the total weight coming in at 1,900-grams for a medium with a shock. Geometry has also been updated - there's a longer reach paired with a shorter stem, and they've gone with a shorter, 42mm offset fork. The goal was added stability but without taking away from the nimbleness that cross-country bikes are known for.
| It rides a little bit more like a trail bike. They changed the geometry, especially in comparison to the Era. As soon as I got used to it, it is a lot more stable descending. As soon as you get your weight in the right place, it is also a lot more stable around corners. That is a huge advantage on this course in Andorra with all the slick roots and rocks here. All the geometry changes and the updated Brain have really improved the performance.
This week is the first time I've ridden the bike. It is always challenging to get on new equipment and getting it dialed in. Luckily my mechanic Brad and I have worked together for over three years; he really knows how I like my ride to feel. He was able to get my suspension to feel like it did on the era. He also made some other changes to get it to where it is now. One of the biggest challenges with a new bike is to get used to the new center of gravity. The dropper post for this race helps me as I do not have to worry about the seat and navigating around it. I can put my body where it provides most stability.
At first, I was a bit skeptical with the short stem and tried a longer stem, but I settled on the 60mm one. My position on the bike is almost identical to what it was on the era. I feel confident as I feel I am not making huge changes mid season yet gain performance and handling.—Kate Courtney |
Courtney's Epic is rocking a 60mm stem and a party post, albeit a short-travel one.
The new Epic employs an equally new shock and Brain setup that's bolted to the disc-side dropout.
Something tells me that Raphael Auclair is a fan of carbon and electronics. His 100mm-travel Pivot Mach 429SL is a tech dork's dream, with carbon rims and cockpit from ENVE, and Fox's iRD electronic lockout that allows the compression settings of the fork and shock to be changed at the same time with a handlebar mounted remote. Raphael is also running Shimano's XTR Di2 setup, or at least the rear derailleur, shifter, and required electronics. The front of his drivetrain is a Rotor REX-1 crank with noQ non-oval ring, and there's also a tidy chain guide from Paul Components that acts as extra insurance.
The simple and classy looking Paul Components Chain Keeper guide is the antithesis of the battery powered suspension and carbon fiber frame and components.
Unlike a lot of World Cup rigs, Auclair's stem isn't slammed as low as possible. Instead, there looks to be 20mm of spacers under his stem. He's also running Maxxis' fast rolling Ikon rubber.
More carbon fiber, more electronics, and yet another dropper post for the Vallnord cross-country course. This red rocket is Reto Indergand's BMC Fourstroke 01, another bike with Shimano's XTR Di2 drivetrain and Fox's Live Valve suspension. The dropper post is KS's LEV CI that offers 65mm of stroke and weighs around 450-grams thanks to a carbon outer tube and pared down components. The Vallnord course is no joke, and tire choice is one of the most important decisions that a racer can make; some roll the dice on mega-light rubber, while others opt for something a bit more robust. Indergand has gone with a set of Vittoria's Mezcal tires, sans tubes.
Indergand prefers organic pads for his XTR Race brakes, and he's also running a very trick carbon fiber guide that probably weighs about as much as a sheet of paper.
Did you spot that tiny silver square on the inside of the fork arch? Many World Cup cross-country and downhill racers are sticking these silver-colored squares onto different parts of their bike, and while they look like tiny GPS trackers from a spy movie, their true intention is much more interesting. They're made by Axxios Technology, a Swiss company that says that their AXS Sensor System is able to allow a rider to go faster thanks to their tiny silver stick-on squares providing a ''massive reduction of the negative impact of vibrations of the bike.'' How much faster? ''Among the best racers in the world, the improvement is 1 second per racing minute; among amateur pilots, time saved is even greater, about 2 or 3 seconds per minute.'' Those numbers are no joke when you at the level of Mathias Flückiger, whose bike is pictured here.
Axxios claims that the AXS Sensors on Mathias' bike reduces vibrations by 26-percent.
Axxios says this is possible due to a series of small oscillating circuits (capacitors and inductors) inside the stick-on AXS Sensors that act as very fast access energy reservoirs. I'm going to let them explain how the system works: ''Whether in a solid, liquid or gaseous medium, the AX Sensor acts directly within the material by inducing atomic diffusion. It affects the electrical and mechanical properties of the material onto which it is bonded, by means of electromagnetic interactions. Effectively, because this material and the AXS Sensor are of different natures, a difference in contact potential is created at the interface, since the energy required to remove an electron differs between the two materials. All potential differences give rise to an electromagnetic field that affects the basic material: higher elasticity modulus, higher natural frequency, and reduction in amplitude of parasitic oscillations.''
More vibration control is said to equal less fatigue, better performing suspension, and more traction, but does it actually work? The AX Sensors are being used in motorsport, human-powered sport, and industrial fields, but I'd have to try it myself before becoming a believer.
But I guess since AX "affects the electrical and mechanical properties of the material onto which it is bonded, by means of electromagnetic interactions", it's gotta work, right? Ha ha...
You would think a bearing race made from other materials then standard steel would have a better effect then a sticker.
AXS have a lot of marketing people, but not a lot of engineers
I'll bet that they're just repackaging a viscoelastic sheet in sticker form... They sell tons of this stuff for quieting down vibration in vehicles, air ducts, motors, etc... It's also really cheap.
ie:
store.secondskinaudio.com/damplifier-pro-20-sq-feet-trunk-pack-12-sheets-butyl-vibration-sheets-cld
@Thustlewhumber: There are different ways to dampen out vibrations or avoid resonance and for each of these approaches there are different ways too. One approach is to balance out a wheel using weights. This is most common and makes a lot of sense to do. It is well worth the weight you're going to add but as I mentioned previously it may be near impossible to do if you've got liquid sealant in there. I think another WC DH racer added weight to his frame, wasn't it Jack Moir? And I read somewhere (ex 4X racer and current EWS racer) Jared Graves likes a bit more weight here and there too, though I'm not sure whether that's actually balanced weight. But as for the AXS technology, it isn't claimed to work by adding mass here and there. In fact they may actually try to avoid it, which is why they stick it close to the axle (onto the hub shell).
One other way is to change the stiffness. And that isn't just the E-modulus. It is about the structural stiffness actually. So the amount of material, the shape of the cross section or other reinforcements matter too. This includes tensioning, like we do with wheel spokes, guitar strings etc.
Now what this AXS technology claims to do (I just read the article, haven't done any further research) is to change the stiffness of the base material (magnesium fork lowers, in this case) by means of electricity. And the electricity is generated due to electrochemical reactions between the base material and their sticker. Now this is where I am out of my depth. Yes I do know you can do this with certain ceramics. Your speakers (or maybe just the tweeter) work this way. I wouldn't be surprised if this could work to some extend on metals too. I can't give you a resounding yes there (and nowhere did I do so), but I wouldn't say no either. If it works as they say it does, I would be concerned about corrosion though. Not sure how quick it will go, but the aluminium or magnesium it sticks to is going to corrode. Steel and titanium may be better off but that could very well be the reason that it won't be effective there either.
As you note, if there's actual current flow between the patch and metal (which the paint may prevent), then all you'd get is corrosion.
The other massive problem is that frames are made from a massive variety of aluminium, titanium and steel alloys, in an even wider variety of tube profiles, connected through different bearing and linkage layouts. That means they're all going to experience different frequencies and modes of vibration during the same conditions. These patches would have to be custom for each bike, both in design and placement, to target the specific freq and mode characteristics of each frame, but they aren't.
Essentially, there is no single credible piece of justification in their provided explanation for why these patches should work.
"Reducing the amplitude of each vibration through the interaction at the very heart of the material by diffraction effect, our product..."
axxios-tech.com/bike
Diffraction isn't even an electrical effect, in the sense of potentials and currents, etc - it's the divergence of electromagnetic waves during wavelength-scale interactions, such as passing through a thin slit. Funnily enough, the same 18th Century scientist, Thomas Young, is credited as pioneering both the Young's (elasticity) Modulus of materials *and* performing the first electromagnetic wave diffraction experiment, to prove the wave-properties of light, so it's almost like someone at AX/ Axxios has just thrown those two, unrelated concepts together after reading his page on Wikipedia, in the hope no-one would fact-check them.
I am more than glad that those bracelets spawned such reasonable discussion, makes me think that Humanity actually is developing
It isn't all about stiffness though. Damping matters too. I heard that it is more the resonance which makes a frame feel uncomfortable than the actual knock. You hear it when you tick it. Wood sounds dull no matter how much wood you use. So a wooden frame would dampen a lot of vibrations hence would probably feel comfortable. Aluminium is really resonant, steel and titanium are slightly below that but apparently enough to make it noticeable. As for carbon, I don't know. I'm tempted to say it would be more in the resin used than in the carbon fibres themselves.
@Smevan: I do know the Youngs modulus can't be changed through metallurgy. I also know that piezoelectric materials can stiffen under an electric charge. What we have here is not metallurgy, they're not changing the alloy. Agreed metals like magnesium (fork lowers) or aluminium (hub shell) aren't piezoelectric ceramics either. They are reactive though, it shouldn't be too hard to get a current running if you damage the coat and attach a metal sticker to it. What is being explained in the article is something that resembles a piezoelectric process which, as I mentioned, is a subject I'm not comfortable enough with to either completely slay or believe. It takes a more thorough article by the company itself for me to develop a stronger stance. And based on that, a bit of background research too. As it is now, they stick these to pro bikes only so it is not something I should worry about at this stage. Most of all, remember that this short explanation isn't first hand. Even a quote could be out of context. I've read quite some stuff where it became quite apparent that the journalist completely slaughtered the well intended explanation of the company representative. I know a professor who, because of that, refuses to give an interview. Because they write nonsense and put his name underneath. But yeah as it is now, the article hasn't convinced me that it does actually work yet none of you has convinced me either that it doesn't. Seems like a few people have a hard time accepting that.
As for diffraction (sorry, still haven't checked their website, just your response) it seems they're referring to the physical vibrations. You can do that. It is like playing an open string on a guitar and then gently touching the string just above the 12th fret or near the 5th or 7th. They call these harmonics in music, or frageolette. But it is a form of diffraction, isn't it?
I suppose if they ever plan to offer such tuning service to the general public, they'll publish their own explanation. Most likely though, they won't. The general public is not likely to accept accelerated corrosion in their fork lowers or hub shell as well as the sponsored athletes are.
Anyway, I'm reading stuff here in PB that hurts more in a bicycle related context. People need to have their saddle high to apply more power on the pedals? Really, which athlete can apply more power seated than standing up? And we need a steep seat tube angle for technical climbing? I've never seen anyone ride up a really technical climb while seated. I guess low gearing, high saddle with a steep seat angle is great for grinding up long steep fireroads. But calling it like that is never going to sell. But as long as that stuff is being published, I guess AX is free to sticker up pro bikes, aren't they?
"none of you has convinced me either that it doesn't. "
fact is, you shouldn't listen to some random dude on the internet. you should listen to what science says. and what science says (you can verify it with any Electromagnetism Textbook, or Optics) is that AX claims are just a big flaming pile of pseudoscientific horsecrap. It's a trick as old as the world. you cover your snake oil with some nice words that resemble those written in a proper scientific pubblication (go to any antivaxxer or chemtrail site, you'll find the same stuff) but taken out of context, mixed up and intepreted in the wrong way. as a scientist, i'm everyday frustrated by this kind of stuff, especially when i realize how many people fall for these kind of scams
Quickly checked the Axxios website (thanks @Smevan), couldn't make much out of it. It doesn't necessarily seem to revolve around piezoelectricity and I couldn't see how they wanted to increase stiffness. It seems like they want to excite the atoms in some kind of anti-frequency to counter the vibrations induced by the trail. See, I could have studied all I wanted about electricity and I still couldn't have bust this. I guess PB and Axxios just need to have a chat then, explain the matter so that we can sleep at night again. Maybe they even have an application that helps against snoring.
@vinay Piezoelectric materials don't stiffen (change their modulus) under voltages, they *deflect*, which is not the same thing - they elastically expand and contract. There's also no instruction on the AX website, or evidence in this article to suggest that the finish is being stripped first, to allow direct patch contact and even if it was, the aforementioned corrosion would then be a problem.
What you're describing with guitar strings is not diffraction at all, but a phenomenon known as "standing waves". What you're doing with a natural harmonic in guitar is touching the vibrating string to introduce a "node" (a point of zero displacement) and force the string into a higher mode of vibration. Incidentally, it's funny you mention the lack of resonance in wood and guitars, in the same post. Wood is not inherently dead to vibration at all and an important thing to understand is that damping affects specific ranges of vibration frequency, so components/systems will always respond to some vibration freqs with resonance. Vibration freqs and modes are also heavily affected by the way the material is used, so you need to look at the component geometry, as much as its material, to assess how it will resonate.
If nothing here is convincing you that these patches are rubbish, then I'm sorry to be blunt, but it's because, as you've shown, you don't understand the relevant physics. You wouldn't stand a chance of understanding Axxios' explanations anyway though, because they're completely nonsensical:
"Several effects also arise as a result of the displacements (compression – expansion) of the vibrations in the material and the induced magnetic field:
the resulting eddy currents are responsible for the occurrence of mechanical forces (Laplace), which counteract the vibratory flow"
axxios-tech.com/systeme-axs
"Vibratory flow" is pure pseudoscience - vibrations don't "flow" and you don't counteract vibrations with eddy currents, since eddy currents do not produce vibration and are not a consequence of mechanical vibration either. Vibration of a non-magnetic alloy cannot induce the alternating magnetic field Axxios claim is producing eddy currents either, so that pat of their explanation is ridiculous too.
Indeed should have kept the E-modulus out of it too. Piezoelectricity can be used for damping purposes though though reading through their material, I don't think this is what they're doing (see my previous post).
As for convincing me whether it is going to work or not, that simply doesn't work this way. It takes a clear explanation from Axxios about how it is supposed to work. Until then I stick with what I said in my first post: it might work, maybe it doesn't.
yes. diffraction (and refraction) are wave phenomena, independent from the nature of waves. their manifestation can be different but the mechanics behind are the same.
"As for convincing me whether it is going to work or not, that simply doesn't work this way. It takes a clear explanation from Axxios"
well Axios can say whatever it wants, but no words are enouh to go against the laws of physics, my friend.
en.wikipedia.org/wiki/Seismic_refraction
a couple of examples
>That's still not diffraction. Diffraction is interference of waves due to obstacles. I don't think diffraction could be used to dampen vibrations.
They tried it in DH first, giving them for free to some big names. They tried it a little before ditching it. But then the free add was done for AX.
I don t understand why pinkbike is giving them this sort of exposure. AX must have given good €, and if not not, it s just stupidity !
AX anti-vibration pad, what, like -- a piece of lead or tungsten weight with double sided adhesive?
Perhaps yes if something is balanced, you would negate some vibration due to imbalance, but this is probably some huge End of the Rainbow BS!
Link please, lol.
If this is how they work, then the theory is at least sound for their principle of mechanics - just how effective they would really be depends on the surface finish, bond adhesive quality and numerous other factors; results would be largely self gratifying in that they would probably end up dampening much smaller, higher frequency vibrations running along the frames finish surface [paint] and sensor adhesive rather than mitigating actual core vibrations running through the component and frame - this would leave the measurable results extremely subject to bias of the manufacturer and almost impossible to quantify a true effect.
...... or I could be talking total BS
The issue is that Saying that even mr Fluckinger can win a second on a lap is just ridiculous, as I strongly doubt that even Nino is able to deliver such consistency to come within 1 second repetitevely on 20-30min lap. Even on fkng road bike on flat course.
In general bike industry is excellent at exploiting the fact that in MTB variables are many, with human factor being dominant and saying this shaves a second or three and when it doesn't, they will tell you: but track was wet and ruts got deeper.
Cooling fons on a shock most likely help slightly, but are probably there mainly for the looks. The only dry (yet still dirty) parts on a bike when riding in the rain are the brake calipers, the rotor and the surrounding areas (frame and hub) and rear shock (the effect is not as noticeable on the fork due to higher oil content and higher system mass and no leverage ratio, thereby greatly reducing the damping energy density).
-I recall many years ago Nico Vouilozz upset about his frame decal weight , so why would an XC bike want deadening material? Less vibration ? Isnt that why we buy carbon frames?
skip to the analysis...
www.tsb.gc.ca/eng/rapports-reports/aviation/2014/a14w0177/a14w0177.asp
An unexpected high rotational imbalance was created on the number 3 tire when it failed during takeoff. During landing, the failed number 3 tire was spun by contact with the ground and was maintained at a rotational speed that was the same as or very close to one of the natural frequencies of the main landing gear (MLG). This caused the lock links to trigger (through the proximity sensors gap) the proximity sensor electronic unit (PSEU) to de-energize the solenoid sequence valve (SSV), thereby relieving system pressure from the extend port of the unlock actuator. In this condition, the excessive vibration then caused the lock links to overcome the force from the downlock springs and unlock the stabilizer brace as a result of gear dynamics, which led to collapse of the right MLG.
...or, if all that fails to make you vibration free....you can still rock your spandex on the road circut.
solutions.3m.com/wps/portal/3M/en_US/Adhesives/Tapes/Support/Technical-News-Articles/?PC_Z7_U00M8B1A00NI60IDFIPS8T3HR2000000_assetId=1273695394295
- cue the collective laugh of pinkbikers with 30mm flatland bmx stems on their endurobroooo bikes.
IFIFY