Faserwerk Announces 'Rockstock' Carbon Bars with Viscoelastic Damping

Sep 30, 2020 at 7:43
by ARC8  


Faserwerk integrates a viscoelastic damping layer into the Rockstock carbon handlebar that reduces vibrations by a significant amount. The 189g light, 800mm wide handelbar withstands the most stringent testing.

Faserwerk is a new component brand of kreuz+quer, the company behind bike brand ARC8 and bicycle.engineering. Thanks to an investment in a manufacturing facility in Taiwan, we are in full control over all aspects of the product, be it design, layup, production process, quality control or testing. The first MTB product to come out of our new facility is the Rockstock handlebar.

The Rockstock is not only our first handlebar, but the first carbon handlebar on the market to incorporate a viscoelastic layer, reducing vibrations. But let's look at the Rockstock's numbers first:
Rockstock facts:
• 800mm wide
• 20mm rise
• 9° back sweep
• 6° up sweep
• 31.8mm clamp diameter
• 189 grams
We think that is not bad at all, before even talking about the damping feature.

Before we can get into the fascinating world of layup development and damping, we have to talk about the design. Design of a handlebar seems easy, but it is not. We went for 6° up sweep and 9° back sweep because that feels the most natural with handlebars only getting wider. 800mm seems the reasonable upper limit, but there is enough space for the controls to cut it down do 740 mm.

We tested a lot of different designs, and there were two consistent findings in all that testing: Having a smooth transition from the 22.2 mm diameter at the grips to the stem clamping are is key for a light and strong handlebar. And we basically could not find an advantage in using a 35mm clamp. 31.8 mm would end up being lighter and stronger, and we could not find anyone wishing for a stiffer carbon handlebar. So handlebar design may look very simple, but as testing of other designs showed, it is still a key element for a high perfomance product.

Layup Development
Layup development started with a simple FEA, done in Femap. Using a constant wall thickness, we can identify stress distribution and major stress directions.

Based on this, we can start designing our laminate ply by ply in Laminate Tools.

For each ply, we see distortions of the ply we have to expect when wrapping it around the mandrel, resulting fiber directions and warnings if there are areas with too much distortion, which could result in wrinkles or gaps in between fibers. This depends on where you start to apply your ply and in which sequence you wrap it, so we can set that in Laminate Tools. Also, if we force a reinforcement to follow a certain path, Laminate Tools allows us to simulate that, as you can see in th picture below. Such simulations would not be possible in FEA without a draping simulation software like Laminate Tools.

After we have built the layup, we can analyze different aspects of it, like total weight, number of plies, thickness distribution or what fiber directions are present at a certain location of the product.

This layup can then be directly simulated in FEA, with a lot of tools to look into the results a traditional FEA could not offer. The reserve factor plot quickly shows how far we are from an appropriate strength.

Navigating to an element that fails and creating a stress/failure index plot through the laminate there shows us which layers carry load, and which layers fail. That is not necessarily the same, as a layer that does not carry a lot of load can still fail due to an unsuitable fiber direction. It is also more information than we can get from testing on an actual product. So if we have a failure in testing, going back to Laminate Tools helps us to better understand the failure.

After identifying the reason for failure, modifying the layup and simulating it is done within minutes, a vast difference compared to the hours of work to create a new real sample. So as impressive as the actual numbers of the Rockstock are, it only took 3 iterations of prototypes to get there.

Viscoelastic Damping

When it comes to carbon bars, there was always one talking point: a lack of comfort. This is why started to look into options to increase damping. We tested various materials and methods. Finally we found one that significantly increases damping without lessening the strength and only adding 5 grams in weight. A viscoelastic layer is embedded in the laminate.

How does a viscoelastic layer work?

As with all damping, a viscoelastic layer transforms kinetic energy into heat. To go more into detail, when the laminate deforms under load, interlaminar shear deforms the viscoelastic layer. Instead of bouncing back like an undamped spring, internal friction transfoms this work into heat. So we had to identify areas with high interlaminar shear to make best use of the damping material. Thankfully, that was easy since we already had the FEA model where we could identify these areas.

So, how does that translate to what the Rockstock makes different than a carbon bar without viscoelastic damping? If you hit something, your handlebar deflects and bounces back. Without damping, it would now keep swinging forever. Luckily, there is natural damping in a carbon handlebar. With the viscoelastic layer, we achieved double that damping. While double may sound like double as good, the actual effect is much bigger. Look at the diagram below which shows the response to an impact. With viscoelasic damping (black curve), the vibrations caused by the impact have basically died off 0.3 seconds after the impact, while the sample purely made by carbon (red curve) is still visibly swinging after one second.

Enhanced Control Over Your Bike

Now that we went through the physics of damping, what does that mean for your riding? Imagine you hit something really hard while riding. Your handlebar will deflect significantly, more than 20 mm in our impact testing. Which is good, because a) it smooths out your ride and b) it means your handlebar does not break. But what follows is less ideal: without damping, your handlebar keeps wobbling for some time. A wobbling stick between your hands and your bike is certainly not what you want. So the faster we can stop it from wobbling, the more precise you can handle your bike. Remember the diagram above: With viscoelastic damping, the wobbling basically disappeared within 0.3 seconds. Without it is still wobbling one second after impact. If you are riding at 36 km/h that means you covered 10 m of trail with less than ideal control of your bike.

Comfort and Health

Excessive vibrations can cause discomfort and even injuries, as Lewis Kirkwood greatly explained in this interview. Putting your hand on the handlebar will add damping similarly to what our viscoelastic layer does, but what does that mean? Your body needs to absorb the energy stored in the handlebar. This can lead to effects like arm pump, reduced grip strength, numbness or inflammations. So by adding damping into your handlebar, your riding gets more enjoyable, and you can do that extra run while your friends need to give their arms a rest.


ISO does not specify any impact testing for a MTB handlebar, which seems quite irresponsible. There is however a test for BMX, where a weight of 10 kg drops from 500 mm height onto one end of the handlebar. That is quite a stringent test, but with the Rockstock, we passed double that requirement despite the handlebar only weighing 189 grams.

The Rockstock is in stock and can be purchased through the ARC8 website or selected dealers.


  • 198 0
 For all the whining in here, I think it's awesome when brands show their work clearly. I'm still not sold on vibration damping bar claims in general, but this is a lot better than nebulous "x percent more comfortable" style marketing. Definitely interesting stuff!
  • 6 0
 Good point well made.
  • 13 0
 Review needed ...
  • 4 1
 I applaud their ingenuity, and love what they're trying. I also like the engineering based marketing, But it seems a bit over complicated. Many motorcycles have rubber cones sandwiched between the fork upper crown and the handlebar clamps. I owned/rode a dirtbike with it for 5 years and only recently realized it wasn't a solid mount when I was looking to buy bar clamps for a different motorcycle. I know it's different with mtb but if you want to reduce vibrations, rubber is a great way to do it.
  • 23 0
 Just as a person genuinely interested in the development process in a sport that I enjoy, it's great to see a company walk through it step by step. Really cool to see stuff like this on Pinkbike. I think a lot of other people really enjoy the factory tours, interviews etc.... Thanks PB!
  • 27 0
 IDK, putting silver colored stickers on my rims seems like a better option
  • 3 0
 It’s really an interesting article
  • 1 0
 Couldn’t agree more.
  • 10 0
 That instagram crop could have been much better, other than that, completely agree.
  • 4 0
 @hamncheez: lol! better get out my power balance bracelets too!
  • 9 1
 A couple of points, for trail riding where you ride up the hill first, you really don't need vibration dampening. It's only after run 7 or 8 at the bike park do your hands start really feeling it. The current full carbon MTB vibration bars are still too stiff and don't really do much over nondamped handlebars. Twisted engineering makes a bar for moto, this works ok for MTB, but it's heavy and looks a bit stupid on a mountain bike. The Fasst Flex handlebar with pivots works great, but falls apart after 2 weekends at the bike park, then need to be sent back in. The guys who make it claim otherwise, as expected. Rev grips run loose work pretty well. I think most people end up running them stiff, which kills the point Currently, there is no great solution, maybe this bar will work, we need to see a video of rough dh riding, with the camera showing how much the hands are moving. The one hit video is nice, but it's not one hard hit you have to worry about, the fork takes care of that, it's high-speed chatter where you have to squeeze a handlebar so it doesn't fly out of your hands.
  • 4 0
 I think vibration dampening can make a difference. Just trying different components made with carbon or aluminum, you can notice differences in ride characteristics even when the components are not specifically made for dampening. They may subtle differences, but some riders may put more value on it.
  • 1 0
 @mark4444: I love my revgrips. Noticable difference. Plus, probably because they don't move around in your hand as much, they last at least double as long as regular grips.
  • 4 0
 @kcy4130: along that note, I have a totally patentable idea I'll share: what if we put this rubber layer closer to the source? Like a layer of rubber between the wheels and the ground?
  • 4 0
 @Weens: You'll tyre of that idea soon...
  • 2 0
 I like a loose rev grip @mark4444:
  • 4 0
Its not the same.
You don't crank a motorcycle
Infinite stiffness is great for pedaling, pulling up on one side down on the other.
Infinite stiffness may help steering feel, maybe.

Verticle flex would help smooth hard landings (one up bars are designed for this)

The vibrations aren't just from chassis inputs, your creating them by landing on the bars with your body weight as well.

Its like ringing a bell.
Check out spanks white paper about developing the vibrocore bars.

More flex means that they can move further while vibrating.

On a motorcycle they are trying to get rid of engine vibes mostly. Also you often don't yank the bars quite the same..... using the throttle instead and holding the bike with legs.
  • 1 5
flag mark4444 (Oct 1, 2020 at 8:13) (Below Threshold)
 @englertracing: I read spanks paper, which sounded great until I saw the photo of the test matching which does not have hand grips on it, it connects directly to the bar, Which I think we would all agree, gripping the bar without grips, would suck, and you would absolutely feel a lot more vibrations, especially the high-frequency ones that they claim to get rid of.

Which leads to my last point, why do people who write "white papers" always come up with rubbish?
  • 1 0
No they don't claim to get rid of vibrations but to shift the natural frequency of the bars to a less irritating/higher frequency.

Also yes they should have the weight of a hand to better simulate real conditions
  • 63 0
 « And we basically could not find an advantage in using a 35mm clamp. 31.8 mm would end up being lighter and stronger, and we could not find anyone wishing for a stiffer carbon handlebar. »

So great to see a brand doing what they found to be the best, based on technical aspects and data analysis, and not what they think people would like to buy.
  • 6 3
 Funny because I’m riding an alloy renthal lite (760 x 20) which is 35mm. And I find it far more confortable than my renthal carbon (800 x 10), which is in 31,8. Don’t know, maybe it’s the alloy, but my wallet thanks me.
  • 4 0
 @iadesp06: I had the same experience. I love my 35mm alloy bars because they're just a little more flexy, my last attempt at 35mm carbon bars hurt my hands.
  • 7 1
 @iadesp06: Maybe it´s the alloy? Like seriously you have doubts about that?
  • 5 1
 Yep. 31.8 done right works just fine and can either achieve all the stiffness you need or all the compliance you need depending on brand/material involved. 35mm looks cool and yeah, on a DH bike where some seek every bit of stiffness they can eeek out of whatever part of the bike they want it...then yeah, go with 35mm. But for most of us mere mortals, 31.8 works just fine.

That said, the IRD Manticor handlebar I have is 35mm and a VERY comfortable carbon layup. Just because its’ 35mm doesn’t mean it isn’t going to be comfortable.
  • 1 0
 @iadesp06: It's the alloy
  • 10 0
 35mm looks cooler though. Just like Kashima coating, there's really no point other than aesthetics
  • 4 0
 @stumphumper92: 31.8 isn't dead
  • 1 0
 One good thing with 35mm is that you can slide the bar in/out from the stem easier, but you rarely need to do that.
  • 38 1
 Meh, I just use anti-vibration stickers instead
  • 58 2
 Same - I stick one on each forearm and I'm good to go.
  • 4 0
 @mikekazimer: I'll be looking forward to video proof of you riding with Dynamat on your forearms.
  • 2 0
 too much effort, PowerBalance wrist band is all you need
  • 1 0
 they dont stick because my bike is already covered in snake oil...
  • 34 1
 30% body fat is the best damping system you can buy.
  • 9 1
 29.9% is where it's at
  • 3 0
 @onemind123: thought it was 28.99
  • 2 0
 Having used this system for the past few years, I can say that it all depends on the viscoelastic properties of the skin holding said fat in place. Full review tomorrow.
  • 2 0
 @vhdh666: that's so 20.19
  • 27 1
 This was incredibly refreshing to have a company treat their audience like they're intelligent people. Thank you Rockstock for taking the marketing high road!!
  • 10 0
 Except you don't even know the company's name. That's why marketing is important.
  • 2 0
 What about "bestest evarrrr fast fast swoosh" made you feel less intelligent?
  • 16 0
 - Rockshox?
- Rockstock.
- Say again?
  • 2 0
 @rickybobby18: No. Beads Gob
  • 9 0
 I honestly think the most damping from the cockpit is to be found in grips. I'm currently mid 'bro' experiment, swapping out lock on grips for push ons (currently on ODI AIRE F1 Floats) and the amount of negative feedback ( numb hands, wrists, arm pump, claw hand) I get is very much minimised. Obviously this is anecdotal evidence on my behalf, but it's absolutely made a difference. Oh, And it cost £17 for the privilege.
  • 15 0
 Yep, agreed. I still don't understand why we're trying to get compliance out of bars when grips exist. I've asked for it a bunch of times, but I'd love to see a narrower bar diameter so grips could be thicker but have the same outer diameter. 19mm is used in kids' bars so it shouldn't be TOO hard to get it done for full size bars.
  • 1 0
 I went from ESI grips to Bontrager lock-ons and the benefit was immediate. The ESIs always ended up compressed under my hand after only a couple rides, their padding crushed halfway to the bar. Not only that but one mild wreck and they'd shred. The Bontragers have so far proved to be superior in every way, especially comfort and durability. I got the 32mm dia SE lock-ons. Super happy thus far.
  • 1 0
 @brianpark: that's a great idea!
  • 2 0
 It would seem like such an obvious fix... Also great for us with small hands and short fingers. And maybe not using half of your soft grip thickness with hard plastic to make them lock-on...
  • 1 0
 I love my revgrips
  • 1 0
 Wolf Tooth Mega Fat Paw Cams. Enough said.
  • 2 0
 @brianpark: I love the new Deity Supracush grips for that reason.
  • 1 1
 @Lotusoperandi: I've been on the fence with those grips forever. They are the ugliest thing I've ever seen, so ugly ive been willing to sacrifice comfort. I'm always function over form, but they sooooooo ugly.
  • 1 0
 Oury Grips are the best sin the biz! Thick and gooey.
  • 14 2
 Bye bye 35
  • 3 0
 I've been saying this since 35mm came on the scene. Nobody has proven any advantage over 31.8, its just broscience and aesthetics.
  • 5 0
 Needs more backsweep. Like Paul Aston says:
I have been using the SQ Lab bars for a couple of years now. This 30X bar has 45mm rise, 12º backsweep, and is 780mm wide (790mm with grips). I use this because the extra backsweep is more comfortable and in one week cured some tendonitis that was building up in my arms for a few years. I usually use the 16º version...

I'll second that the 16 degree bar solved some terrible wrist pain I was having when riding daily.
  • 4 0
 Yeh, I wish more companies would offer a 12 deg backsweep bar.
  • 1 0
 @tremeer023: I can assure you, Aston was true. I wanted to get better ergonomics of riding cockpit on my 4X frame but for cheap money so I almost headlessly jumped on this XLC 780mm wide 50mm rise 12° backsweep handlebar and it's perfect.
On Rune I use 777mm Spank Spide EVO handlebar so I didn't bother trimming this XLC handlebar and I like them a bit more than Spike. They have sort of natural feeling and ride is more comfortable.
I have a rule that saddle must not be higher than handlebar. If it is, then the bike is of wrong size, wrong geometry or cockpit is worng. I think that even today with "modern" geometry 99% of riders have their handlebar low or too low, below the saddle height.
XLS for crazy 25eur
  • 16 9
 And this is why german marketing doesn't work in North America. Show me some steeze goddamit!
  • 27 2
 I love German marketing. It appeals to me greatly.
  • 30 0
 Science is steezy
  • 3 0
 to quote the voice of our science classroom: "science ruuules"
  • 2 0
 @noplacelikeloam Speak for yourself. I'll take this technical marketing over steeze and bullshit claims any day.
  • 4 0
 @cedrico: it was tongue in cheek. I dont disagree. :-)
  • 1 0
 They're not German, they're Swiss
  • 7 0
 I'd be curious to see the plot of a spank vibrocore for comparison
  • 3 0
 Agree. Before I bought some I was pretty sceptical of vibrocore, but they weren’t much more and still cheaper than carbon. Really like them, they definitely have a damped feel.

Would be good to see some back to back, real world vibration testing with some different bars.
  • 2 0
 Love my Spank Vibrocore bars, made a big difference in arm pump on long runs and over a long day.
  • 1 0
 quick question guys, does the foam inside your vibrocore bars degrade with time? is the damping still good after two or more years?
  • 2 0
 > With viscoelastic damping, the wobbling basically disappeared within 0.3 seconds. Without it is still wobbling one second after impact. If you are riding at 36 km/h that means you covered 10 m of trail with less than ideal control of your bike.

> Putting your hand on the handlebar will add damping similarly to what our viscoelastic layer does, but what does that mean?

These don't track. If your arms are damping (they are), you're not going seconds at a time with a vibrating bar. There's an argument for more flex (reducing peak G) and more bar damping (reducing pump), but not for 'less than ideal control' from lack of bar damping if your arms are doing the same work.
  • 1 0
 It would have been possible to put grips on the bars and add a few kg to each end to simulate your arms. But I expect the effects would look less impressive in the plots.
  • 4 0
 I think their point is that their bars add damping, reducing the amount of vibration your arms need to absorb, reducing fatigue and increasing control?

If you look at their time-response graph, their bars also reduce the amplitude of the force.

Not sure how much all this translates to ride feel or quality but it's interesting.
  • 2 0
 @Paddock22: I think that's what they meant, but that's not what they said.

I'm actually more interested in this technology on the road side. There are a lot of light carbon leaf-spring designs that could benefit from more damping (Canyon's VLCS, Trek's IsoSpeed, various fork designs, etc.).
  • 2 0
 @alexdi: you and I are on the same wavelengths. I had the same thought about road/cx/gravel bikes. I feel like this application of material is more applicable there since they are *mostly* rigid and have less tire.

I have a Trek Boone CX and it does have a little piece of rubber/elastomer around the isospeed pivot. If I am being totally honest though I can’t tell how much of a difference the isospeed system makes as a whole. It’s probably more of a cumulative affect as opposed to something that be acutely felt. More damping may help but there not a lot of movement there to begin with.
  • 1 0
 @mountainsofsussex: Yeah, pretty much. Not hard to dampen a system with so little mass. Add your arms, heck, even grips to the mix? I'd suspect that the results would be negligible.
  • 1 0
 Fat and muscle wobbling around also converts movement to heat (aka damping... possibly also dampening- via sweat, haha), but results in fatigue. That doesn't mean you will notice an improvement with these bars, but it's probably not going to hurt. I'd still go for an alloy bar with the geometry and grips of your choice over any vibration damped bar.
  • 4 0
 Fill your bar with lead fishing weights and rubber bands, this my friends is the path to the promised land!
  • 3 1
 Interesting concept - would be interesting to see the graph comparing other bars rather than just their own without the layer. Shows there is a difference in their design but not against the competition.
  • 1 0
 YES - finally a brand that says what we all know already - NOBODY IS ASKING FOR 35MM CLAMPS. Since this stupid trend started i've seen more people swap handlebars than i've ever seen in 20 years of biking. Those stupid brands randomly make a thicker handlebar, then try to somehow make it feel closer to the older standard which was better. sometimes we're such an obtuse sport.
  • 3 1
 Will they resit Sram brake clamps? It seems most handlebars failure I have seen where at the brake mount, and always with a sram brake.
  • 1 0
 @mollow: sram should have a collar or shim under the clamp to spread the load.
  • 1 0
 Well, I'm not jaded, but, handlebar, stems are the future, in my opinion. "It's a stem, it's a handlebar, it's a home run for the whole family". m.pinkbike.com/photo/16846298
  • 3 0
 I was not able to get the IG clip to pan down using telekinesis.
  • 3 0
 If you say Rockstock three times in a row real fast it becomes Rockshox
  • 3 0
 Do I have to say it in front of a mirror? And more importantly, will I get killed to death?
  • 3 0
 40mm rise please! not all of us want a low front-end.
  • 3 1
 My bars will deflect more than 20mm in a big impact? Whaaaaaaaaa? Is it just me, or is that more than expected?
  • 1 0
 I'd probably not be surprised to see that much. However, their plot shows pk-pk 20g, not pk-pk 20mm. The similarity in numbers makes me question the press release slightly. And the centre accelerometer is vertical while it looks like the outboard ones are probably fore-aft.
  • 2 0
 Vital did a bar deflection test a while back. Oneup was 21mm youtu.be/uPHvBgm1Vvg go to the 7 minute mark
  • 2 0
 @DHhack: Yeah, I don't doubt that it is possible to deflect bars that much during a benchtop test, but the article suggests that a large impact during riding could cause over 20mm of deflection. I just highly doubt that when you consider compliance in suspension, tires, arms, etc.
  • 2 0
 @coast2coast-4: mount a GoPro to your top tube and point it at a grip and go hit some drops to flat.
  • 2 0
 @DHhack: Lol now I'm very curious. I might have to try this although my setup will probably be 10x more hack with duct tape and a smartphone.
  • 1 0
 @coast2coast-4: I need to see this! Ideally need to have a rigid reference in shot too. I originally thought a bit of bamboo cane but that would wiggle to much. Maybe just add some bright markers to the ends of your bars
  • 1 0
 @coast2coast-4: that could work LOL
I put one on my seatpost once to see if the seatpost or the seat stays flexed more on an old hardtail of mine
  • 1 0
 Finally a bar that isn’t the standard 8x5 or 7x5 sweep and rise. Have always liked 9 degree back sweep and a 6 degree upsweep but is kinda tough to find anymore.
  • 1 0
 Interesting now there are 3 bars focused on ride flex/damping (oneup, these guys and I forget the last one). Always good to see more innovation.
  • 2 0
 I like this kind of stuff. For an engineer it's more valuable to see this, than a guy riding in the woods.
  • 1 0
 Curious what materials are used as a viscoelastic layer in a presumably pre-preg carbon layup.
  • 1 0
 Just saw the 20mm rise though. Might try a set when they come in a 30mm riser.
  • 1 0
 I have some extra dynamat from quieting down a box van, glue some dynamat to your bars instead of grips.

Same thing, right?
  • 1 0
 Stuff it inside yours bars. It helps a lot.
  • 1 1
 the weight seemed awfully bouncy in the stress test video. I assumed that it wouldnt have bounced as much with all the vibration dampening magic discussed in the article.
  • 7 0
 Depends on the frequency Kenneth
  • 2 0
 lol buy carbon bars for stiffness then make them less stiff....
  • 1 0
 I still do not get why we went from 31.8 to 35mm if 35mm is so stiff, This flies way over my head.
  • 1 0
 curious to see these tested against the one-up and enve bars
  • 1 0
 Baseball bat test like Evil Bikes or I'm not buying!
  • 2 0
  • 1 0
 Fill with an expanding insulation foam - like Great Stuff. It works.
  • 1 0
 I like the pretty colors on the graphics
  • 2 1
 More rise por favor
  • 1 0
  • 2 2
 that weight tho, for an 800mm bar? Amazing.
  • 2 1
 A little terrifying tbh.
  • 2 1
 Look mum.... no teeth
  • 2 4
 over-engineering at its finest
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