Here's That £300 3D-Printed Titanium Stem You Wanted

 I don't care. Look at it.

 @mikelevy: I know right, it's hideous. Just carelessly sandblast your alloy stem to get the same surface finish.

 It has titanium gills

 Absolutely! I'm not against additive manufacturing, in fact I really like printing in FFM and SLA myself. But I absolutely hate it, when it's used in places, where it's not needed, simply to be able to put the 3D printed buzzword on it.

 *FDM (phone autocorrected)

 it's also an absolute hive for mud and crap to get in.

 but it would be awesome for internal cable routing

 @Tambo: Just wondering what you've based this comment on?

 Any time the terms "generative design" or "topology optimisation" are involved, it seems to mean "a guy trusting software to make decisions without realizing that they're bad decisions, so that you end up with something inefficient and stupid looking".

Additive manufacturing has definitely enabled this buffoonery.

 @darkstar66: His brain and the brains of people he knows.

With enough material, you can always make something strong and stiff. For the torsion loads (pulling one end of the bars, pushing the other) it does help to not have an interrupted cross section. But the resultants of the shear stresses due to torsion are diagonal and those lines are still there. It can be sufficient. But "stiff" isn't something binary. Maybe they want to tune for a certain bending stiffness (up and down) and torsional stiffness so that's when you want to play with thickness and height variations in the cross section, including removing material altogether.

Just learned I don't have a brain, apparently.

 OOOHHHH pretty, how do i get 300 cursive "L's" to buy one...?

 @mikelevy: Nice but agree with some of the comments. If you are going down this route there are better options for engineers. Take a look at Tom Sturdy’s website. www.sturdycycles.co.uk If I had the cash that’s what I’d be buying and no I have no connections to him before anybody accuses me of marketing.

 @AgrAde: so, why don't we use full rods to make alloy frames?

More material isn't always better. Bending and torsional loads have their peak stresses in the outer regions of the stresses area. More material inthe middle does not help with this. The only cases where the middle of a part gets roughly equal stresses, is with pushing and pulling axial on the part.
If you pull up or oush down on your handle bars, your stem gets bent. So you end up with compression on one side and stretching on the other. If you lay a line between the peaks, you will see that the middle of the part has pretty much no stress. Therefor, if you know your load cases, you can cut the middle section out and go closer to your accepted stresses (e.g. Rp0.2 x safety factor).
I see why one might try it and when you have it working, why not sell it.
Is it the best case for 3D-Printing? Probably not, but there are worse examples of over-engineering.

 Guys, I think my Giger counter is clicking

 @Hairyteabags: Sturdy's printed parts are made for them by Metron anyway. so the "better options for engineers" are the same engineers.

 Hitting a new low in the comment section, a PB editor complaining about bike stuff being too expensive. That's our job

 @almightybenners: Thanks didn’t know that.

 April fool's comes early?

 @Phipu: I think he was aiming at the holes in the cross section itself, at least that's what I was responding to. To complete your comment, it isn't just the axial loads (pulling or pushing) that more or less distribute the load equally across the area. Shear (so due a load normal to the axis) does that too. But these are a fraction of the local stresses that can be introduced due to the bending and torsion moments. As on most bikes these days the handlebars are much longer than the stem, it is the torsion which will be bigger than the bending moments. Exceptions may be triathlon, BMX and trials setups. But on mountainbikes, torsion is dominant and a closed cross section is the most efficient way to transfer that load. But again as said, maybe they're trying to tune the different stiffnesses and that's why they may have chosen to leave some sections open. One other reason could be to limit the stress concentrations at the bar-end and the steerer-end. As odd as it may appear, leaving out parts could help them make sure that the loads are introduced in the parts that are best able to pick up those loads. This isn't uncommon. If you have a sharp 90deg transfer from one plane to the other and you don't have room for a fillet (for instance because something has to fit there), you can make a nice rounded groove to guide the stresses along that round groove instead of close past that sharp corner.

Of course the issue here isn't that there wouldn't be room for a fillet. But apparently they do want to transfer those dominant shear stresses (whose resultants are diagonal, as I mentioned earlier) from the bolts clamping the bar to the bolts clamping the steerer. They either don't want stresses in these other parts or there isn't that much stress there even if there would have been material. In CNC, removing more material because it is not needed takes time, machine wear and energy (and sometimes the tool can't even go there). In additive manufacturing, it is the other way around. If you don't really need it that much, you'll save time, energy and material if you don't put it there.

But yeah, I don't have a brain.

 @Phipu: A start would be to google the difference between closed section vs open section beams, and how they respond to torsional loads with regard to shear stresses. Then have a go at googling stress concentration factors.

When you've got a bunch of complex and interacting loads ie tension/compression/bending/torsion, and you're designing a part that's going to see cyclic loading, then using large closed sections with simple geometry and good surface finish is where you START. This doesn't have any of those things.



"why don't we use full rods to make alloy frames"

We use tubes because tubes are a closed section beam that is very easy to produce with optimal grain structure, surface finish, and with butting and hydroforming, optimal geometry. We arrange these into a truss to balance the needs of the frame - strength/weight/stiffness. We use triangles to reduce the bending moments on the beams.

To apply the same logic to a stem, you would use a tube between the steerer and handlebar. One and done. With the strength you need, and the size that it is, any sort of truss structure makes no sense at all. Use a tube, just like everyone else does it, to make much lighter, cheaper, simpler stems than this thing. To use solid beams arranged in parallel would be absolute nonsense, but this stem does exactly that.

 You could go and put your ass on the line and buy aa 3d printer like he did if it frustrates you so much , start banging out those products

 @Hairyteabags: lol you do know its the same guy that makes them for sturdy and i have no doubt based on what i have seen that dimitris will know and have studied more about cranks than anyone ive come across that owns the 3d printer

 @Compositepro: Why buy million dollar machine when BBB stem do trick?

My bbb stem weighs 14 grams more than this thing lol. It's forged, it's simple, it uses a high strength alloy, and it was 30 dollars.

 @AgrAde: its the same as any 3d optimization process using a computer you get to a margin of error via validation and work from there via testing , you can then trust the software , happened for years for if you follow the development of CFD in F1 and the like correlating thetunnel .....to the simulation and then trackside result to the simulation result till you are within a few percent of what happens in the real world , Same with the emerging world of topology , and thats before we even look into post processing a 3d print to fix it , however always remember this GIGO mean Garbage in Garbage Out

 Hey, but it has holes you can run your cables through!

 @Tambo: but you need the holes for the bar and steerer

 @brianpark Can confirm the Newmen Evolution SL is such a good product. I've been running it on one bike for six months and have another on it's way for another bike.

It's received comments from XC nerds at a local race and from Enduro bros in the bike park, which is a rare thing.

 @Compositepro: garbage in garbage out being the key phrase here.

You need good engineers to drive the software. You can trust the software only when you understand it, know its limitations, and know what it's telling you.

 @Hairyteabags: better engineers ? the guy designed every winning track bike for the UK cycling team for the past 20 years thats 70-90 odd olympic gold medals on stuff he designed , was the UCI technical guy till he decided to leave to do his own thing? and from memory is the head of design at pinarello who just happen to win the tour de france a few times and , you know is the guy who designed the latest hour records mashing bike out of 3d printed aluminium , and thats without talking about the other stuff he does outside bikes , bit like calling ken block a learner driver buddy well done

 @AgrAde: my My Ferrari only does 11 mpg but it puts a smile on my face if a bbb stem puts a smile on your face remind me never to go into a lap dancing bar with you

 @Compositepro: nah. Weld them on. Don't forget to route the cables through first though!

Honestly stunned that @agrade is about the only one who seems to get it.

 @Compositepro: the thing is, Ferrari don't market their cars as econo-boxes. This stem blares on about high tech design and manufacture, but is no better than an item that can be banged out in their thousands from comparatively basic materials using conventional manufacturing methods and conventional design...

 5 DEV

 I was thinking the same,even check the weight of my 30 mm Newmen E.SL, 88 grams, 89€.
100% agree that stem made no sense,well said!

 @Phipu: … like the length of this post

 @Tambo: i dont think he gets it from the other end ....as someone who now has a dentist for a girlfriend i can join the ceramicspeed rapha ....dubious gains club ..... like many things out there sometimes its just because you can .... its pretty high tech ... you have the latest and greatest topology DIY software making the decisions rather than you plugging extruded bits and lopping them off in solidworks to get your design, then using the unsexy methods to make stuff , i mean everyone out there has a forged then machined stem .....some cheateing wankers even miss out the forging part , tossers, shiny new 3d laser wizz bang stereo printers are new and unless you actually know about them seem dead exciting......anyway im moving on to computer heatsinks those 19 13900 chips need an answer to their throttling issues

 @Compositepro: yeah, 3d print is wonderful! But FFS use it to its potential. And if you're not going to do that, please don't harp on about the fancy optimisation etc; just tell us it's made to look funky because that's fun and you've got a £500k printer sat around gathering dust.

 @mikelevy: there’s not many parts that look like they’re worth the money they’re being sold for. However these imo look amazing,the way they’re made and the material used makes this a premium product that’ll I’ll probably buy.

 @AgrAde: .....you did read the comment part about real people in the real world actually validating the results you know so they understand it know its limitations etc ?

 @Tambo: Its their machine they can do what they want with it if they have fancy software optimizing their design criteria who am i to judge , funky looking things sell and id love a 500k printer sat around first thing id make is heatsinks for the electronics industry or topology optimized lattices for implant surgery as its about the most usefull stuff i could see a use for

i suppose when you were marketing BTR then you were correct too in your assumptions and the belt and braces approach you preferred will appeal to a market chunk , the one thing i learned with bicycles is people buy with their heart arguing technical superiority with the 0.01% of people who even technically gave a shit or have an interest is not going to get me afford a yeti money

 @Compositepro:

Yes, but it doesn't mean that they took a holistic design approach. I'm sure the numbers that the software spat out are correct. I'm sure the design is optimised as well as that design can be. It will have hit a sort of local maximum for its design parameters if I can use that analogy. Using fundimental engineering concepts would have allowed them to find a better solution.

There's no point harping on about "high tech" topology optimisation when your design is poorly optimised. Either optimise it properly or just give up and make something that looks cool.

 @Compositepro: aye, there's a reason I'm not in marketing.

 @AgrAde: theres no point bangng on about anything, you and I may be missing some big bits of information, another massive aspect is its often the look of something that sells it , sure make a thinwall tube stem with internal stiffeners and all that shit hidden on the inside like a thomson x or a profile or whatever , but reality is your dentist buddy isnt going to look twice at it, you will have blown 300 bucks on dullness, i used to have this issue with industrial designers and their swoopy carbon fibre shit that they would then go ok engineer fill the mold.......you would kind of sit there and go shit so many problems guy you do know how carbon fibre works?? I now have to do x y and z to get your less than optimized stuff to work and its going to add weight and lose stiffness and risk cracking , but it sure does look nice they set their design criteria by drawing a nice swoopy industrial designer type thing and met them the wrong way round , your design criteria , could be the best stem on the planet technically , you knocked it out the park with the two guys who give a shit about it being the best product on the planet they probably wont buy it because they know rationally a 30 dollar stem is ok and they're broke , you will find them arguing about in on some obscure forum section never to be seen again However if its unusual you might have a chance , a bit of hype sells, a clever bit of marketing well your into the big market, Ceramic speed , Absolute black, Kogel companies that makes money from selling things you could argue technically for eons about if you were stubborn enough , dave on the other hand is a mamil and building his dream bike , this stem has just enough viable real hype to make it onto his parts shortlist and is weird looking enough to get his juices flowing ,maybe the unusual hype train isn't your thing maybe you are the messiah that sees through this , but like me too you aint never going to be rich by selling a product based on your best of everything design criteria (and even in my engineering career compromises get made everywhere for a whole raft of reasons ) because well the holistic viewpoint doesn't stop at the engineering design of the component it extends to beauty being in the eye of the beholder, uniqueness a whole load of other shit that maybe just us engineering types don't get but people who run succesful companies do , i mean would you buy a cybertruck over the more practical competitors in the UK the L200s Toyotas Nissans I guarantee someone will ?, who knows they might not sell any maybe its a showcase product to get work you will be amazed how cycling products seem to get people interested in using a company for something else

 @Tambo: me too , though to give them credit i got suckered into the toilet seat from japan

 @AgrAde: ps this is the reason i never ever speak seriously about anything on the www it gets boring

 @mikelevy: speaking purely of the finish it reminds me of a cheap alloy stem deanodised with lye

 Most engineers still use CAD for AM. DfAM tools are slowly getting adapted out there but I think one big gap that engineers face is that they have to step into CAE tools to leverage AM properly. The tool chain gets quickly expensive and the AM reward on most components isn't there to support the move. DfAM tools also produce results that visually may challenge appreciation from customers - organic shapes can be scary when your ride depends on it - and you can't or shouldn't rely on generic material properties to assess mechanical integrity of parts. Tools like nTopology are changing the game though - I don't want to be a bully or a troll here but in terms of AM, the Atherton bikes aren't particularly impressive neither... ROI of AM is bling in nature for the bike industry mostly. Happy to be proven wrong though!

 @AgrAde: "To use solid beams arranged in parallel would be absolute nonsense, but this stem does exactly that."

Ok, let's start here as this seems to be a key part of the misunderstanding. Sure, the point of a product isn't necessarily that everyone realizes what's so amazing about it. But if you're putting such an incredible amount of effort into criticizing it, you could just as well put a fraction of that effort into actually looking at the product. Give it a shot. Done? Indeed, those beams aren't parallel.

Beams in parallel would be the equivalent of a radially laced wheel. It may work nicely in a front wheel for rim brakes or for no brakes. There is no axial moment to be transferred between hub and rim. If you do need that (for a drive/rear wheel, hub brakes etc) your spokes need to cross. That's what they're doing here with the stem too. The dominant load the stem has to transfer is the torque of the bars being asymmetrically being pushed and pulled. So these beams run diagonally along the outside of the stem between the bolts.

Is this the amount of better that should encourage me to replace what I have? I'm running 26" wheels, 32mm fork stanchions etc. It works for me and the marginal improvement (if any) of what's available now isn't worth it to me, yet clearly it is for some. People were hucking Rampage cliffs with 32mm stanchioned Boxxers until just over decade ago or so, but apparently people have progressed so much that 32mm is too tiny for a trail bike now. If people feel they need something big and burly now, I'm not stopping them. I'm more than happy enough with my forged Spank Spike stem and I don't see why I would need something else, yet lots of people seem willing to spend twice that for something that essentially does the same thing. Now that someone made something through a different approach doesn't make it a bad approach, even though the product doesn't even outperform what's available now. New stuff never is. Back in the days, metal airplanes weren't better than what the wooden ones have evolved to be. And when they started with composites, they weren't making better planes out that than what they could do with metals (actually because they should go back to the anisotropic way of thinking with wood). So yeah, this stem isn't necessarily lighter than the well evolved stems we use now. But the thinking makes sense and it could evolve into something more refined. So if you don't want/need the product as it is now, excellent as I don't either. But you're questioning the thinking itself whereas it is your own thinking which is skewed.

Look at me, talking like that when I don't even have a brain...

 @AgrAde: Well it must have been a shit school. Removing material to produce stiffening structures, or adding in this case, does indeed.....drum roll....make the product stiffening. It also increases the strength to weight ratio.....

 @mikelevy: Will this team be spec’d on the GrimDonut v2?

 H.R. Giger?

 @maglor: and bees

 @mikelevy: Look at it after a muddy ride

 @darkstar66: never mind.

 @AgrAde: I love all of the engineering discussion but is this e bike compatible? I want to buy this for my weekly 20 minute ride on a green trail with my sworks turbo kenevo sl.
I think 20 minutes on an ebike is like riding a standard bike for 40 minutes. Why wouldn't you ride an ebike when you get more exercise in a shorter time?
#birdsarentreal

 @AgrAde: I don't even think they trusted the software. Says "manual topology optimization". Probably means they looked the FEA and just blindly added material to the CAD until the red spots went away.

 @almightybenners: But who designs them? Metron has the printers for making, doesn't mean Sturdy isn't doing the designing.

 @Tambo: " Ferrari don't market their cars as econo-boxes" This isnt being marketed as an econo stem ? A Ferrari is no better than a Ford ,If that frame of reference is that it will get you from A to B ., Ford's can also be banged out in the thousands from comparatively basic materials using conventional manufacturing methods and conventional design. "I" would love to experience the driving / arriving in a Ferrari feeling at some point in my life so would others , some will shun that opinion in favour of cheaper automobiles as their mode of transport , Moral of story different strokes for different folks

 @thewanderingtramp: A Ferrari IS better than a Ford if you want to display your wealth or taste (or just give the impression of having those), or just envelope yourself in precision crafted carbon, titanium, Inconel, etc, instead of marginally crafted steel and plastic that was "banged out in the thousands".

 @mikelevy: look at it after a muddy ride..............

 Stems get chosen for additive manufacturing for the same reason they were such a common early CNC product… they can be manufactured in a small machine, with a reasonable cycle time.

I use Wren stems for weight-weenie builds. Half the weight and 1/6th the price of this. I’m sure it’s not as stiff, but whatever. I’ve never been riding a MTB and thought “man, this bike would be so much better if the stem wasn’t so flexy”

 @Hairyteabags: LOL Your comparison in context =

Major league Baseball vs Little league Baseball.
NFL vs College

 I concur with your sentiments on the Newmen stems. 4 bolt for my enduro ride, and 2 bolt version (~70g if I remember correctly) for my trail and hardtail.

 Funny flex for newmen, but, legit point.

 @thewanderingtramp: I think you either missed or ignored the context of my comment.

 @reimaru: was thinking this too. (go to the museum in switzerland if you haven't)

 @Auto-XFil: My stem (Spank Spike) is 35mm long. I'm not sure whether I could even feel the flex in the stem, compared to the flex in the bars themselves.

 @maglor: Pro tip: don't crap in your stem.

 @Moonshot20: Isn't that what the Swat box in the rental fleet is being used for? Crapping in a stem requires next level precision dumping skills. Especially whilst riding. The Swat box should be doable during low speed cornering practice.

 I just ordered a stem from amazon for $27CAD that is 129 grams.

And get this, the page says that it is

"Good Design - Special colorful design, exquisite workmanship. Unique sectional profile lends the torsional stiffness required by our users."

 @vollmAir: and internal spider webbing.

 @brianpark I don't know. Stems with two face plates love to lose bolts or, worse yet, washers when one of the two pieces hits the ground.

 @eluder: I think he's referring to the new version which is a single piece of metal with two bolts in the face plate. It's an excellent piece of design.

 I’m just glad it’s going to make routing cables/hoses through the stem so much easier.

 @darkstar66: Shit school? wouldn't really matter, School is what you make of it.

If the strength to weight ratio is good then why is it heavy? Why does it even need stiffening structures?

It's heavy and needs stiffening ribs inside it because the open section lacks inherent stiffness. Not only does the open section remove stiffness compared to a closed one, but by removing material from the extremities of the section and putting it into the middle instead, you're lowering the moment of inertia of the section. Which means that you're using your material less efficiently in terms of providing stiffness.

 @AgrAde: That were true it it were the case. There is no material in the center of the cross section.

 @Tambo: NO as there is no other way to read your suggestion , an item can be replaced by a cheaper item, this works for nearly all products, depends on what your parameters for evaluation are. You are correct Ferrari do not market themselves as the cheap motor , my resonse was that the stem is not being marketed as such either.
So the example set was a high end low volume item vs a mass produced econo box item Ferrari vs Ford , many people are happy to buy a cheaper mass produced option and go fro A to B using that vehicle but the market is not complete , people like a bit of luxury in their lives if they can afford it, which was my point.

 @vinay: I'm looking at a fair amount of material inside the stem near the handlebar which seems to be adding stiffness to what would otherwise be flats.

If you're stiffening individual members on something that small with that much material in it, it's time to ask yourself if there are better options.

 @AgrAde: You mean the part that looks ribbed and widening towards the bar? These don't seem meant to stiffen the diagonal members. Instead it appears like they want to create sufficient clamping surface at the bars (as for the bars these are out of plane loads so you need to spread them) and what you see would be to transfer it into those diagonal members. CNC'd or forged and then CNC finished stems are hollow too by coring them out from the faceplate-end. They still need the same amount of surface at the bar (as it is the handlebar that limits how little clamping surface is still sufficient) and that will just go on for the entire cross section as they can't taper it from the inside. Most brands obviously taper that area from the outside (looking at your typical stem from the top down) yet here with this stem they could play with the inner shape and not leave it constant. But yeah, what you're seeing there isn't to stiffen these members. It is to spread the load on the bars and transfer it to said bars.

 @thewanderingtramp: compositepro said his Ferrari only get 11mpg..... My point was that that would only be disappointing if Ferrari had sold the car as being economical. This stem is being touted as light and stiff, yet does neither of those better than many cheaper alternatives. The Ferrari at least drives and handles and sounds awesome compared with a poverty-spec Civic, but this stem only looks 'better' than its competitors. Sure someone will still buy the stem, but that doesn't validate the marketing.

 @HankHank: A simple, forged aluminum stem with non-stupid design and quality ti hardware. Who'd have thought?

 @Tambo: i read stiff and holes in the same sentence and my mind drifted in an entirely different direction than what all engineers in this thread seem to be discussing.

 @mi-bike: I guess all the clichées aren't that far off... :-P

 @mi-bike: sensible. But you're on the wrong website. You should be on the one about hubs, not stems.

 @Tambo: here's an example:
bikehub.co.za

 @vinay: I disagree that they're not meant for stiffening the stem.

I mean, you're right regarding the clamping surface and load paths to that surface, but my eyenalisis of the thing is telling me that they're also meant to increase stiffness.

 @AgrAde: I think we can probably agree; I wouldn't put this one my bike even if it was given to me.

 on*

 @Tambo: best you stick to flying in airplanes while not understanding how they work…

 @Tambo: I could save 14 grams though

 @AgrAde: but you'd have to see that waste of tech every time you looked down...

 @SonofBovril: seems I've got a better grip on how to make aeroplanes than most people

 @Tambo: I could feel like I'm justifying my degree every time i peer down towards my stem and judge it harshly. I'm getting hard just thinking about it.

 @Tambo: at the rate things are going in the uk im going to have to get rid of it anyhow and buy a mclaren

 @Tambo: we need the guy back in the comments who said dont compare aeroplanes to bikes

 @brianpark: Or better yet a '3D forged' stem for $10 that weighs only 143 grams and comes in sick colors. Would be great to see this stress tested against more expensive options, wouldn't be surprised if it's actually stronger.
www.amazon.com/gp/aw/d/B09DFX3342?ref=ppx_pt2_mob_b_prod_image

 @Compositepro: it's a good point!

 @DoubleCrownAddict: Forging will always give you the best product because of the way the grain structure forms near the surface. That said, I'm not too sure whether the stem in your link is actually forged. The surface quality and the errors near the edges make me think it is made by investment casting, which in turn doesn't get you such a great grain structure. Good forged stems don't have to be expensive though. Mine is from Spank and I think it is really great. I don't know about weight though. I think the weight of a stem doesn't matter that much as it is pretty central. The parts it holds are pretty crucial so I'd rather see it do what it should and has to weight what it has to to do its job properly.

 @mikelevy: SHUT UP!

 @mikelevy: have you seen Locked Components 3D printed stem? Much more gorgeous, lighter and a bit cheaper?

 Don't worry Pinkbike commenters, an ACTUAL engineer who ACTUALLY works with additive is here to call out all your (and Mythos') ridiculous bulls***.

First off, all you keyboard engineers who think putting holes in something makes it less stiff. WRONG! This looks a lot like a truss style structure to me (diagonal lines everywhere). Truss structures have been around forever, and work great because they can be light, strong and stiff. See: cranes, bridges. Because I'm a total nerd with far too much time on my hands I did my own little FEA experiment, and hey what do you know, cutting some holes out of simple round and square section stems had little effect on stiffness. This plus Ti has a higher elastic modulus than Al, this stupid titanium stem with holes in being stiffer than an average stem feels easily believable. My FEA also showed a strain distribution that pretty much explains exactly where the design for this overpriced chunk of titanium bragging rights probably comes from - the material in the corners doesn't look like it does a whole lot, so they cut it out.

Second, those webs on the inside of the stem are not for stiffening IMO. Integrating super thin webs of material into a part to support other bits of the part during the process is really common in design for additive. They're probably no thicker than the spot size of the beam (around 0.4mm) and probably melted using a fast and low energy parameter, giving them roughly the load bearing properties of aluminum foil. They probably weigh less than 5 grams total. To give Mythos credit, keeping these in as a design feature is pretty genius, and far better than the stupid meshes everybody else seems to use when they design for additive.

Third, someone at Mythos has definitely given this the full can o' Bri'ish baked beans, because if my very rough measurements are correct its like 5mm thick on the sides which is total overkill (assuming my FEA is anywhere near right). I get they're used to designing roadie stuff, and I guess thought that us off-roadies would just want something burly that weighs a ton, and they're kinda right actually? Nevermind, good job Mythos, but make it lighter for the apparently very prevalent XC crowd in the Pinkbike comments next time.

Fourth, comparing this to any composite stem is totally pointless, because this will survive an impact, and your carbon stem will delaminate and snap. At least after your carbon stem brakes, you can run one of these without a weight penalty after all the weight you've saved by not having teeth any more. Downside being I'm not sure you'll be able to say Mythos with a lisp. Comparing it to alloy stems, is it really that much heavier? I've got stems from Hope and Burgtec which both are about 150g for a 40mm. Plus they're advertising weight with bolts which barely anyone seems to do- if they put Ti bolts on it (which for this price they really should) there's an easy 10 grams saved.

Fifth, it's nice to see somebody finally make an additive mtb component that uses an obviously additive geometry. Everybody thinks Sturdy and the Athertons are doing such a good job making round tubes with additive, but its a total waste. Athertons could take loads of cost out of their lugs if they just welded them out of Ti tubes and still keep every other feature, including the custom sizes, and they'd look basically identical. Sturdy's bikes look super nice, sure, but do they really look THAT different to any other welded Ti tube bike? I will say though Mythos could definitely have done a better job with this design, could easily be lighter, surface finish needs work, whole thing looks like a rush job to me.

Just my 2 cents, but this smells like a marketing exercise to me. Put their name on the front page and in the mouths of the people by making a wacky half-baked stem with very little time, effort or money. Does it do everything a stem needs to do? Yes, it holds a handlebar onto a steerer tube. Does it do anything else functionally? No. Does it "play to the strengths of additive"? Probably, I bet they spend less time making these than the combined lead time and shipping time of your average Taiwanese CNC shop. No tooling needed either, so I bet they'll tweak the design every time they make one.

I can't decide if I like this thing or not. I believe their marketing, and I'm interested in them as a company, but this feels like unjustified and overpriced additive bike bling just as much as Atherton bikes and Sturdy. Equally, I'm not sure what other features I actually want to see from an additive stem, I think I'm more pissed off with their marketing than I am the stem itself.

 @breeze-eng: What I like about Robotbike/Atherton is that they used double shear lap joints where the lugs hold the carbon tubes. I doubt Hope is doing that with their machined lugs. If you hold the tubes on only one side (inside or outside), the delamination could still start from the free edges. I trust the Robotbike approach more for that. And it would be pretty tough to weld a lug like that together. For the rest, I already agreed with you.

 @breeze-eng: so, you "believe their marketing" AND you're "pissed off with their marketing" (last paragraph*)? For an engineer this is a remarkable display of indecisivenes!

* I can't really believe I made it all the way to the end of your dissertation. I guess I have too much time on my hands too...

 @vinay: Not a bike expert, but I’ve got enough experience to tell you that double lap joints on tubes are complete overkill for anything other than pullout resistance, which AFAIK is useless on a bike frame. Bonded joints are very often the strongest area of a bonded tube assembly, even if it’s “only” a single lap joint. Single lap joints typically fail by peeling in tension, which is really hard to achieve on a bonded tube. Ideally on a tube you’d use a tapered single lap joint to spread the load evenly between components. I’d be surprised if double lap joints don’t overstiffen the lugs and cause the carbon to fail at the end of the joint. I imagine there’s a lot of additional local lamina in their tubes to counteract this.

IMO the only benefit atherton gain from using double lap joints is decreasing the length of the bonding area, making their lugs smaller, which helps from an additive standpoint. But cleaning supports out of the inside of a double lap joint will be a nightmare, so the benefit they get from the size is likely completely lost on some of their lugs. Anything else anybody spouts about double lap joints being better for bikes is marketing BS.

 @breeze-eng: curious to know how Atherton would achieve their tube to lug joint design with standard fabrication techniques?

 @mi-bike: I believe their marketing is technically accurate, but I think they should be marketing it differently, hence the confusion. As with most engineers I’m good at numbers not words.

 @Tambo: switch to single lap joint, weld small tube onto big tube, bond small tube into carbon tube. Or even better use tapered end tubes for tapered single lap, and weld tubes into lugs as normal. My previous comment explains why their double lap joint isn’t needed, and why they use it anyway.

 @breeze-eng: their tubes are cut from lengths, so no local reinforcement

 @Tambo: it’s not new we used to make flexures for f1 cars using pi joints inner machined outer wire cut and welded and then it taper locked when we bladdered the carbon wishbone……. Some idiot then invented the full carbon flexure

 @breeze-eng: Interesting. I learned to just avoid free edges at all costs. Not necessarily for pull-out resistance, but against delamination. Unless those tubes are UD (which could be possible if they make them with pulltrusion) even pulling or pushing could cause delamination. Most likely they're filament wound, then trimmed. Most elegant would be to insert the tapered connectors in the mandrel so that you can actually use those as the turning points (so that the fibers there are in circumferential direction), slide out the round center piece of the mandrel (so it should indeed fit through a connector), then attach the connectors to the printed lugs. It could get bulky around those turning points though, which may be downside there. Just brainstorming. To which extend you can still get away with single lap joints, I don't know. Would you expect supports in the gap between the two laps of the current design to be needed? I expected that if both of the lips are tapered, they have sufficient support by themselves. Otherwise, cleaning them out may be a challenge but as the tubes have a circular cross section, it shouldn't be too hard to just make a simple tool for that and use it on a drill.

Funny thing is, it seems like I'm defending printed stems and frame parts whereas I wouldn't buy it myself. I just ride a simple steel hardtail and a forged aluminium stem. Works perfectly fine for me. But it is fun to reconstruct the reasoning behind a certain approach. Always better than to dismiss it as a failure right away.

 @vinay: My experience is the same re: the double lap joints. I used to work for a consultancy that specialized in oddball analysis-based design and we had a few mountain bikers that were interested in developing a similar product to the robot/atherton bikes. We came to the same conclusion that robot did - double lap using additive ti paired with off the shelf tubing made the most sense, and the main development cost was getting the geometry of the lugs perfected so that the joint was reliable and easy to glue in a way that took the free edges completely out of the equation.

I'm somewhat the same with regard to adopting these things myself - alu frame and no carbon or ti components here.

 @AgrAde: One possible solution I was thinking of (other than using the connectors as inserts in the mandrel and later on attaching these to the lugs, as I mentioned above) would be to print/cast/machine only the inner lip to the lug. Then have a metal sleeve that slides over the sleeve and then attaches to the lug. Kind of similar to a typical hose connector. Again it may not be the lightest (because you need to connect this sleeve to the lug somehow) but it may be much easier to produce. As for Atherton, I actually expected they would have used pulltrusion tubes which are UD with a braid over it for protection. These are much cheaper to make/buy and I thought often the performance of UD is what you want. Plus, if it is pure pushing and pulling, the UD fibers won't delaminate. After all, delamination starts because of the shear that cracks the matrix. Not sure why they're not doing that. I've had good experience with carbon/epoxy pulltrusion tubes as part of a suspension linkage. They're fine. And cheap. They also do them with glass, aramid etc.

 @breeze-eng: pull-out resistance can be useful on a bike. When just riding along, a downtube is in tension, and when coasting a chainstay is also in tension. Landings, especially to flat, hugely increase those tensions.

 @justinfoil: Yeah, but that's not the issue. You can get the same pull-out resistance just using a bigger single lip. I'm talking about delamination because of free edges. From what I understand, these tubes are made using filament winding. Basically the way sewing thread is wound on a bobbin. It isn't under such an extreme angle, but definitely under an angle. Imagine if you'd have that pattern and you'd pull it in axial direction, the angle between the fibers has to change. If you would have cut the winding in shorter tubes and you'd load it like that, the edges will start to raffle. The matrix (glue/epoxy) that has to keep the fibers in place with respect to each other will crack and this will slowly progress deeper into the laminate. If you can stop this from initiating at those edges, you've stopped the main failure mode of these composites. The best way to stop it from happening is to not have free edges in the first place. I once got a pair of Magura Louise Carbon 2007 brakes where the "carbon" applies to the brake lever, saving a wopping 9g or so. A crash onto the tip of the lever and it would delaminate. I later got their Marta 2009 brake which also had a carbon brake lever, but made from a braid (basically the way your socks are knitted). So it goes around, no free edges. It is way more robust. Not saying I care the slightest about the carbon stuff, this just happened to be what I got back then. Either way, if you can't avoid free edges altogether, the best approach to keep delamination at the free edges at bay is to restrict both faces of the surface. So inner and outer surface. At least that's how I've been taught. @breeze-eng mentions you can get away with these single lips to some extend and for these frames you're still within that envelope. That's his call, I'm not going to argue. I personally don't know to which extend you can get away with it but I don't necessarily question it. More often than not, we're building/using constructions that aren't the most efficient way to get the job done. Just that we're overbuilding stuff so much that we can get away with this. Think of houses, furniture etc. So yeah, it might go for these Robotbike/Atherton bikes too. Is it needed? At least it is more the textbook approach.

 @vinay: raffle ? ffs just stop

 @Compositepro: Sorry, not native speaker. I looked it up, meant to say "fray".

 @vinay: You were right, the stem I ordered is a die cast piece of junk.

 Hurry up my chimney already

 @oatkinso: Let him deliver his presents first.

 Finally!

 Not Santa we wanted, but the one we needed.

 www.pinkbike.com/news/enter-to-win-a-sram-gx-eagle-axs-upgrade-kit-pinkbikes-advent-calendar-giveaway.html

(USA, Canada, Germany, and UK only this year)

 Hey bring this over to the advent page

 ..

 good catch, oh the irony

 Yeah… was looking for this comment, should have been in an Uno, it would have been perfect! But they spent all their money on the stem so they had to get a bike with good value.

 My butler washes my bike, so no problem.

 @Bitelio: upvoted, poor people ewwwww

 This should be top comment!

 Suppose it depends whether you want it or not. Mountain biking is so expensive anyway and a lot of it is for the ascetic too. Only thing putting me of is the 35mm bar clamp tbh. Stems last a lifetime so I’d see it as a decent purchase. Looks very special. But we could all run slx instead of Eewings too. But we don’t.

 I live in the uk and ride most days/evenings in all weathers. I can honestly say when I clean my bike after a wet muddy ride,not once have I thought my stem is filthy…ever! It may have a few bits of splash on it but nothing heavy. I’ll happily run this stem. It’s so nice to see a stem that’s not a block of cnc aluminium with no individual style. This looks amazing.

 @mikelee: You totally can ! It sure looks incredible and I'm pretty sure it has been designed with that in mind in addition to the structure/stress needs. But it serves no other purpose nor issue addressed by the industry on this particular component.

 @mikelee: I agree with you, but I still couldn't justify 300 notes for a stem.

 I have never seen my stem get even a light covering of mud, it is way up out of the reach-o-mud. Look at the webbing in a fork brace then come back and tell me its any worse? For the one occasion you go bog racing I dont think in the grand scheme of things a stem with mud in it will be deal breaker.

 I miss hearing CRT monitors go bWOINgWahwahwahwah when you degaussed them and that warm, staticy feeling when you put your arm hair up to the screen

 CRTs really did not exist until the 1950s.

 @EdSawyer: "The earliest version of the CRT was known as the "Braun tube", invented by the German physicist Ferdinand Braun in 1897"

"The first cathode-ray tube to use a hot cathode was developed by John Bertrand Johnson (who gave his name to the term Johnson noise) and Harry Weiner Weinhart of Western Electric, and became a commercial product in 1922."

en.wikipedia.org/wiki/Cathode-ray_tube

 @EdSawyer: nah the libs invented CRT to indoctrinate kids… oh wait.. I’m an idiot

 @speed10: You gotta know it's the Quantum Dots that do the indoctrinating. So small, no know even knows what they do to help a TV picture, they change when you observe them. What are they hiding?!

 That Cathode Ray Gun used to shoot right at our faces! Every day! I think it made us tougher

 @muumuu: Delicious electrons getting blasted straight into your eyeballs! It's why kids liked to sit so close to the screen; innate need for more electrons! And since electrons are negatively charged, it helps to destroy their natural positivity and turn them all into cynical beasts.

 5Dev customers disagree with you.

 @tomhoward379:
Do they have any customers though?

 @rich-2000: I know at least one plus their insta is full of builds with them on.

 @tomhoward379: exactly the point i was trying to make......marketing and timing

 How about a $300 titanium 3D printed Ibis head badge for your new 4vS frame. I’m working on one for my new Ripley and may decide to sell them.

 Nah, Santa cruz way too mainstream for this. Probably best suited to an Atherton frame to match the lugs...

 And if gorilla tape is used for installing, does Mr Engel approve?

 Well that didn't last long. I also didn't realise the comments get bounced about in the page and don't stay in the order made!

 @bunjiman82: you can reorder them im told I wish they would just do them in most offended order , or list by dumbest f*cker , list by funniest

 @Compositepro: