The new Atherton DH bike with its mix of carbon and titanium is definitely divisive among those who see it. Whether you think it looks wrong or right, the technology behind it is pushing brand new techniques and processes into the industry. The Atherton's are definitely trying to produce something that is very different, so to get a better understanding of how and why these bikes are made, we chatted to three of the engineers: Ben Farmer, Rob Gow, and Ed Haythornthwaite.
What is the process from design to complete bike?
Ben: First you go onto our website and enter your height, arm span, and inside leg length. Our program then shows a suggested ideal geometry. If this fits what the rider wants, then the data from the website feeds directly into the CAD system.
Rob: Basically, all the different lugs are controlled by a formula, so when you put in height, inside leg and arm span, that automatically alters all the angles. If we were to be manually changing this all the time, it would take weeks to design each bike. So, that sort of intelligence is built into the model. Once we have the riders' unique data and their desired designs, we send those to Renishaw.
(Renishaw is a manufacturing company based in Gloucestershire, United Kingdom. They produce the machinery that can print the titanium lugs for Atherton bikes.)Rob: It then takes about 16 hours to produce one bike's worth of custom lugs, based on their unique requirements.
Ben: The Renishaw machine builds the lugs using titanium powder. There is a four laser setup up in there, they all shine down onto a metal plate that sits inside and is spread with a six-micrometer thick layer of titanium powder. The lug is then built layer by layer until the design is complete. This is usually made from 3,500 layers. They are all checked dimensionally - they are real experts in dimensional checking at Renishaw. The lugs arrive to us attached to a one-foot-square plate and they all sit there until they are then cut off. There is then some final machining to be done, like bearing faces for the headset and the bottom bracket.
We then bring in carbon tubes which have been designed to our specifications. Each tube is different, with a separate layup. We then cut the tubes to length and they go into a set of jigs to ensure accurate construction. Next, we inject adhesive into the cavity in the lugs, called a double-lap shear joint. There are three reasons why this style of joint is particularly strong. Firstly, with a single-lap shear joint, when you load that and pull it to tension, it can twist, With a double-lap shear joint, when you pull it to tension, it doesn't twist, It produces what is called "shear forces."
If you ever put a bit of tape on a table and try and pull it off, how would you do it? You would peel it off. What you wouldn't do is try and pull it off, because it would be really hard to get off. That is basically how these work. So, it is very strong. The second thing is when you inject the adhesive, you can witness the adhesive being injected around the circumference of the joints, so you have complete confidence that the adhesive is in the joint. If you haven’t got adhesive in the joint, then you won't have a strong joint. The third reason is that, essentially, these things assemble themselves. You have the jig there to ensure precise positioning, but once the adhesive is in the joint the lugs and the carbon tubes slide together, it's just a case of making sure it is accurate and fully in the joint. It's very easy to assemble.
We then cure the bike at room temperature. This means we are not heating or cooling, so there is no expansion and contraction during the process. If we have it at room temperature, it is basically at the temperature where the bike will be used. In total, it takes at most two weeks to have a fully complete bike, from changing something in the computer to having it being ridden by one of our riders.
What was the idea behind choosing the combination of titanium and carbon for the frame?
Ben: What we are doing is combining the incredibly high specific strength of titanium with the high specific stiffness carbon tubing. All that comes together in a way that is unlike a carbon fiber frame. We design the lugs with a technique called "topology optimization," Which means we define the design space on the computer and then apply the boundary conditions that exist around it like: I need to have a bearing pickup here or; I need to keep the mud out of here, so it needs to be closed. Whatever it is, the computer figures out the best way to accurately use the material so it is not even 1% overused in that area. Actually, a lot of that subtlety gets missed because it is a mountain bike. Also, within the lugs is a variable wall thickness, basically it makes the use of material perfect and all of the parts.
| We can do in a month what another company might take six months to achieve—Rob |
The chainstay yoke offers the best example of this practice, the way this has been designed is to ensure mud falls off of it and to fully optimise the structural integrity of the component. So what we end up with it something with a very high specific strength. All that means is strength per specific weight. Titanium is the highest specific strength metal, for a given strength you have the lightest output. We have very high specific strength metal where the shapes are complex and the loads are complex. Loads come from all sorts of different directions and you have a vehicle with a really weird setup. You have a rider, with not much power, and the rider's main center of mass and gravity is all over the place.
Loads can come from all different directions, so you have a complicated set of things going on. With metals, they are suited to situations where both the shapes and loads are complex because their properties are the same in all directions. Once you move away from those areas of complexities where the loads get resolved, and more simple we use carbon fibre tubing.
Each lug has an incredible level of detail and design work
Carbon fiber does not work well in applications where shapes are complex, because you can't get all the fibers moving in the right directions. They don't work well when the loads are complex, because it is only extremely strong in one direction. So, with our design of using two different materials, what we end up with is something where we have the right strength in areas where we need it and we have some degree of compliance in areas where we want it, and we have stiffness in the other areas we want it.
You end up with a bike that has a very stiff suspension platform but offers some level of compliance. It works really well with the DW6 suspension platform to give impressive levels of grip. So working with Rach, Gee and Dan, they have been providing us feedback on that combination of stiffness versus compliance. We have then been playing around with the layups of the carbon tubing to build a platform which, for many riders, is more than proficient in terms of stiffness. But for the Athertons, because of what they do, they can benefit from the added stiffness. That's been the whole winter's work, really.
Rob: Because we don’t use molds, we can quickly throw in new parts and play about with thicknesses and stiffness on CAD, change parameters, test it the next week, and you have the feedback. That development cycle means we can do in a month what another company might take six months to achieve.
Why did you go with Dave Weagle's DW6 suspension platform?
Ed: The main thing with that is, with feedback, it enables us to get the characteristics they want. The DW6 is one of the few options where you can isolate each of the key characteristics like pedaling, braking, leverage ratios and progression without them compromising each other. Normally, when you adjust one, it has a knock on effect on the other. Literally, they can isolate each aspect - say if they want it to give a little bit more in the mid-stroke or something like that. You don't then mess up the pedaling or the braking,
DW6 just offers huge flexibility, which has already been demonstrated by the tweaks we have done so far. We can do that without a knock-on effect elsewhere. Just works bloody well basically. They can't believe the grip it gives in particularity. When we were originally developing it, they were certainly looking for an advantage on flat corners and off camber, and it really offers that by having that extra confidence in grip. Gee has never ridden anything like it. We are also currently the only ones using it.
Ben: Another reason we use it is because it is very well suited to how we make these frames. Basically, it concentrates a lot of mechanics around the bottom bracket, which means it works well in terms of not having lots of breaks and joints in the carbon tubing. It also just so happens that when we set this up, the rocker pivot is where we need to kink the seat tube, it was all designed in unison. We needed to put a split in the seat tube and that is where we put the suspension. It was conceived as a whole platform that was tunable for the future. We needed it to work with how we were building the bike,
Dave Weagle was driving our developments. He came back with a bunch of different concepts and DW6 was the standout, as it fitted with our construction methods and designs - and it played well with our idea of customization and fine tuning things.
| The DW6 is one of the few options where you can isolate each of the key characteristics like pedaling, braking, leverage ratios and progression without them compromising each other.—Ed |
Could you change the riders' frames between races to adjust to tracks?
Ed: That's more of a question for Gee and Rach. It's more about getting the bike spot on for them and not the track. Once they have something spot on, they don’t like changing too much throughout the season. Should you actually change a bike for different tracks? The majority of the time, no. Once they have that bike setup dialed, you don't want to change anything major. Most of the development work we are doing now is to get the bike dialed. They may tweak very slightly, but nothing major.
What have you changed on the bike so far?
Rob: All the bikes so far have had slight tweaks, as they have tried to cram in as much testing as they can. We give feedback to Dave Weagle on DW6 that we have got from the riders and he will do some subtle tweaks. We also take feedback from Pete, the Atherton's race mechanic, like this bolt is hard to get to or it would be easier if this was here. The next prototype will then have all these features. You can really accelerate the development process and be really active with the constant stream of feedback.
How many prototypes have you made?
Ben: Nine so far, including the trail bike. We started the process in the first weeks of January and we should be up to 20 machines by the first race. At this point, it is been all tiny changes and most people couldn't tell the difference between each bike. The main thing is delivering each rider a custom bike, that they can push it, and be happy about them. Most of the work now is getting the sizing dialed for each rider's custom bike.
Previously:•
Interview: Rachel, Gee & Dan Atherton Chat Business, Bikes & the Upcoming Season•
Bike Check: Dan Atherton's Prototype 29er DH Bike
MENTION: @athertonracing
This article got me 3/4-torqued for sure...
The generative/iterative design tech wasn’t something I was expecting to read about in the mtb world for a very long time...
Seems like you guys are a relatively new company, will it be bike industry focused or where the max demand for the tech lands?
Benefits though, very consistent weld, small HAZ, fast. I do believe they may find a spot in the bike industry eventually.
I’d assume it’d have to be a ti frame manufacturer vs a company like a factory making frames for
Multiple brands
@krashDH85:
check this like for like
Check this like for like
I think robot was too ahead of their time and happy that Atherton picked up where they left off. Excited to see the potential in the coming years.
But why not use hydroformed tube... I asked more than one time to the Atherton's instagram but get any answers back.
Crazy though I know - but it could possibly work.
@gcrider you can cut the hydroformed tubes to the lenght needed.
So this is like the same tech as botox and breast implants?
Yes - it’s like setting up a kids tent.
But wow - this is pretty awesome and almost too simple! The future (?). Have not checked out the site but wonder what pricing will be like.
www.cxmagazine.com/tbt-john-tomac-raleigh-signature-drop-bar-mountain-bike-titanium-carbon-tioga-eric-rumpf
What is the tensile strength of printed titanium?
That said these are being tested by the Athertons?
Probably bomb proof bikes.
Fly on a modern commercial airplane? Both the aluminum and composite ones are actually glued together. The riveting you see on modern metallic fuselages is a secondary load path, the primary thing keeping it together is glue (really fancy aerospace glue, but glue nonetheless).
Here is an excerpt from a whitepaper I found on the matter and why it concerns me a little bit:
Bond Degradation A primary cause of bond degradation in aluminum joints is hydration2,4-6 ((I'm not sure what happens with Ti - vs - Aluminum, I wonder if they bond this in a vacuum as Ti is reactive with oxygen from what I've read))
.
As explained by Davis and McGregor2, aluminum, when exposed to oxygen, forms an aluminum oxide surface layer. Hydration occurs when this oxide layer is exposed to water. This type of bond degradation typically results in a transition from a reliable cohesive failure to significantly weaker and less predictable
mixed-mode failure. This transition results in a weakening of the bond that is not predictable, quantifiable, or easily detectable. Bond degradation can be prevented or at least mitigated by proper surface reparation2,4,6,7. Prebond preparation of the surface is, therefore, crucial to long term environmental
durability4.
A good amount of us ride in extended wet weather climates (I live in NW Oregon). (Why yes, yes I'm a nerd)
Getting appropriate measurements from consumers is quite a challenge. Most people can't describe their own heigh accurately let alone inseam, wingspan and so forth. Mountainbike fit studio?
It is good to be starting on DH stuff with a custom bike just because it can be one-dimensional in comparison to a "trail" or "enduro" bike, as there is no agreement on what those things are or should do.
I am looking forward to as much coverage of their bikes as possible.
One question, do you do any testing for dry spots in your joints? Perhaps you've seen some consequences of this in early testing. With that in mind I'd reckon the glued joints are extremely robust and smaller dry spots will most likely not even be noticed. Just curious though.
The market seems just so saturated with absolute radness these days. Just 3-4 years ago shopping for a bike was easy cause 95% had such obvious flaws. Now it seems like an amazing bike is released weekly.
The difference between my top of the line '17 Yeti 5.5 and my '19 Foxy is an order of magnitude difference in the ride feel, and as a result my overall speed. The Foxy is SO MUCH better. The difference to my '13 Bronson, there just are no words.
If we were talking motocross bikes, you would have to go back 25 years to lose performance equivalent to how much bikes have changed in 5-6 years.
It's intimidating however to build a $4K frame (just a guess) based on what you think you know about ideal bike geo. You also have the issue of selling a one off unit.
Sure I have ideas about what I want but I'd be concerned about doing anymore than just altering a few numbers based on my current 'pretty close' mountain bike.
This is 100% false. Because of physics and that whole all actions have an equal and opposite reaction, you can never isolate suspension characteristics, because all of them are tied together.
I don't think it's so much about 'evolution' of the bonding process, more QC. These guys have "complete confidence"
"The second thing is when you inject the adhesive, you can witness the adhesive being injected around the circumference of the joints, so you have complete confidence that the adhesive is in the joint. If you haven’t got adhesive in the joint, then you won't have a strong joint. The third reason is that, essentially, these things assemble themselves. You have the jig there to ensure precise positioning, but once the adhesive is in the joint the lugs and the carbon tubes slide together, it's just a case of making sure it is accurate and fully in the joint. It's very easy to assemble"
What I wonder is how customizable will it be: can I pick up my own chainstay length, seat angle, reach, BB height, laverage ratio and even anti-squat? I could make my dream bike.
The marketing clain about DW6 let believe it should be easy, although I know this is marketing bs... Actually my dream bike would have a less complex kinematic but you can’t have everything right?
www.youtube.com/watch?v=bq_6DYyZPBQ
I really am curious how this will play out. The customization is amazing. I think the idea/look of these bikes has been awesome since Robot first came out. (also I drooled over those thermoplastic GT LTS's back in the day!) There does seem to be a stable market for custom high end mountain bikes. But, there's only so many of those "PRIVATEERS" that could really benefit from being able to get a custom bike, test ride, figure out how you would tweak the design and then get a replacement a couple weeks later? (Most of the pro riders who could really benefit and have the financial backing to make that possible are most often also sponsored by a competing bike company. And even if they don't have fancy metal "sinter-printers"; they are still often getting one off welded aluminum test rigs to ride, give feedback, modify and test again till they are happy anyway.)
In one of the recent Atherton bike articles on PB. (there's been quite a few!) Rach talked about how their prototypes/ "cast off bikes" become the "team bikes" for other riders because even they can't really afford to print a bike and then just replace it next week. (and it seems the whole benefit of this is to customize to the rider, so if your team riders are riding bikes that were customized to different riders it does call the whole concept into question...?)
It seems like RobotBike didn't make much of a dent in the market because this tech is still so expensive? For sure droves of people have bought various brands and styles of mountain bikes over the years because they happened to be ridden to victory by the Athertons. So it will be interesting to see if that continues. But it also seems like there was a cost/mass market availability to that success?
It sounds like Dan is setting up a "Bike resort training camp"? Maybe someday a person will be able to fill out a form, get a virtual fitting, and in two weeks show up for "training camp" on your custom Atherton...?
Anyway, best of luck to them. Just thinking out loud here... what forums are for!
Yeah other things that could work but realistically titanium isn’t a bad choice
If you look at most titanium frames that have been made very few are designed around the material itself but rather just swapping materials for something designed in aluminum or steel@stiingya:
I’m guessing cheap not part of the purchase process?
www.pinkbike.com/u/Chnoux/album
A friend of mine, during a drunk discussion years ago, were talking about 3D printing. I said once the printers are more affordable, a lot of people will start making very ugly things. My friend, business guru that he is, said "and that's why the money is in templates." Printing can be done from home, but the best designs will come from actual smart people who know what they're doing (respective of the field).
10 years from now there'll be a forum here on Pinkbike where users trade designs on everything from frames to handlebars to helmets. They will be very ugly frames, handlebars, and helmets.
Forums are the current ‘social’ interaction and Buy/Sell is currently for second-hand products, but this will change fast. Buy/Sell and socialise around other users’ designs, mods and upgrades that you can print and hack yourself.
Self-printed spares? Shim stacks? Levers? Bottle mounts lol?
They said their goal is to offer a broad range of options, most likely a top end custom printed one and a cheaper all aluminium one. The bike you see here should be very very close to what´ll be offered to consumers though.
"We’re working with some amazing guys formerly of Robot Bike Co., and they’ll be an essential part of our start up, they are as passionate about the technology and its potential to disrupt the industry and shake-up the large corporates as we are.—Gee Atherton
The Athertons met Ed Haythornthwaite, one of Robot’s founders, when he was Dan’s World Cup mechanic in 2006 and their ongoing friendship was the catalyst for this venture. Ed’s understanding of what works on a bike and his passion for improving a rider’s experience underpins the development of the entire range. Ed’s co-founders, Ben Farmer and Andy Hawkins both come from an aerospace and Formula 1 background. They are experts in composites and additive manufacturing (metal 3D printing) which allows for full customisation of every bike frame."
They also didn’t have a DH bike in the previous line up. Bringing the Athertons on board practically guarantees a WC winning bike.
Only one year))))
Move on people, nothing to see here.