Electron beam melting & vacuums
We sometimes joke about reviewing stems because, well, let's be honest – as long as they hold onto the handlebar and steerer, they're usually not that interesting. Unless we're talking about Mythos' £250 IXO stem, that is. Pronounced "icksoh" and looking like something from H.R. Giger's catalog of bike parts, the IXO is manufactured via a 3D-printing process and the result is a see-through stem that Mythos says is both light and strong.
The IXO comes in 40mm and 50mm lengths, both with zero rise, a 35mm handlebar clamp, and a 38mm stack height. Claimed weight is 136 grams, but the IXO they sent me actually ended up being a bit lighter at 127 grams.
Mythos IXO details
• 3D-Printed titanium
• Lengths: 40mm, 50mm
• Rise: 0mm
• Handlebar clamp: 35mm only
• Stack height: 38mm
• Material: Aerospace-grade titanium (Ti6Al4V)
• Weight: From 136g (including hardware)
• MSRP: £250 (including UK VAT)
• More info: www.mythos.bike
If you hadn't heard of Mythos before, there's a good chance you've never heard of their parent company, Metron, who has been making ultra-high-end components for years, mostly in the skinny tire world. The IXO is their first mountain bike stem and it's manufactured via a process called electron beam melting which does exactly what it sounds like. EBM is similar to the more common Selective Laser Melting in that both 'grow' the component via powder, but while SLM uses "normal" lasers, EBM uses a beam of electrons in a vacuum environment.
If you want to make your bike parts via EBM, all you need is a special gun that shoots out a beam of electrons from a super-heated tungsten filament at around half the speed of light, as well as a barrel or two of aerospace-grade titanium and a hell of a lot of know-how. Mythos is doing that at their Derbyshire facility in the UK, the same place where they manufacture their equally crazy-looking Elix stem that's even more expensive
. After the stem is grown, its clamping surfaces are machined down to hold onto a steerer tube and a 35mm handlebar, and titanium hardware is used because of course it is.
Wondering why you can see through the IXO? Mythos says that they employ FEA (Finite Element Analysis) and CAD to figure out exactly where material needs to be and, as you can probably tell, where it doesn't need to be. The 3D-printed result is an alien-looking shape that Mythos says exceeds the 200,000-cycle test program at ISO-specified forces while also being stiffer under both bending and torsional forces than a traditional stem.Alien looks, normal performance
The first thing I noticed about the IXO stem is that it looks a bit rough, especially in a few spots where the surface seems inconsistent. It turns out that this is a byproduct of the manufacturing process and has no effect on its strength or rigidity, Mythos said, even if it does seem odd compared to the forged and machined aluminum stems we're used to. "Many people believe that 3D printing produces a lower grade material, but EBM titanium actually matches or beats the material properties achieved by traditional manufacturing processes, meeting or exceeding all requirements of the relevant ASTM and ISO standards for Ti6Al4V (ASTM 1107, ASTM F1472, AMS 4999 and ISO 5832-3),
" Mythos told me. So why not give the stem a smoother finish? Matthews explains: "Due to titanium being exceptionally tough, it’s extremely difficult to remove material evenly to produce a smooth or polished finish, and surface finishing the visible interior of the stem is incredibly difficult. This is why we decided on the raw as-printed finish. Plus, what’s the point of 3D-printing something and then making it look like it’s made with some boring old traditional manufacturing process?
There are plenty of boring black stems to choose from and all of them cost a lot less (and some weigh less) than the IXO, but Mythos isn't trying to sell thousands of these things anyway. Personally, I love how it looks, especially on a black bike with a black handlebar, but I do have a soft spot for anything weird.
Forgetting about the price for a moment, are you a fan of the IXO's lines or would you prefer something a little more normal?
Installation is like any other stem; it should sit a few millimeters proud of the steerer tube, and it uses a no-gap faceplate and the same 5Nm of torque for all six of its titanium M5x0.8 x 14mm bolts. The steerer clamp tolerances are a bit tighter than other stems I've used and it needed a good push to slide down onto the tube (no, there were no burrs), but it all went together as intended. You'll certainly want to use a torque wrench for your fancy stem and read the instructions before picking up any tools
The stem that the IXO replaced was a standard no-frills aluminum thing that definitely wasn't doing anything wrong, but the difference on the trail between it and the 3D-printed titanium Mythos unit was... Not at all noticeable, of course. What the hell did you expect? I know that Mythos says the IXO is, "16% stiffer in torsion, and 11% stiffer in bending, when tested side-by-side with an equivalent alloy stem,
" but I'll never feel that while riding my bike because it's not like any 40mm stem a soft noodle to begin with. I'm not saying that it isn't stiffer, only that I can't tell the difference, even when I clamp the front wheel between my knees while trying to twist and turn the handlebar in my faux-science test.
So it's not a game-changer, but it also didn't do anything wrong while I used it, never creaking, groaning, or slipping, as you'd hope for such a high-end component. One thing to note, however, is that riders who've had stems take core samples from their knees might prefer a smoother backside to the steerer clamp.
If you were hoping for a groundbreaking leap forward in stem performance, this ain't it. The IXO does nothing wrong but it's also not going to change your riding in any way, which is pretty much what I expected. That said, if you're interested in the technology behind the stem and like how it looks, which describes me, I don't think it's all that crazy to consider given the other things we spend our money on.
3D-printing titanium is cool AF+
Price to performance ratio-
There are lighter and less expensive stems-
|I'll admit that I don't really care if the IXO is noticeably better or not than an $80 stem because I don't think that's what it's about. If you want tangible performance gains, spend your money on tires, wheels, geometry, suspension, or lessons, not an expensive stem with an interesting backstory. Instead, think of the IXO as a demonstration of technology usually reserved for hyper-cars, aerospace, and the medical field. |
No, I don't see myself buying a £250 stem, but the unrepentant tech dork in me absolutely loves the idea of a 3D-printed titanium anything and how it looks on my bike. Are you into it, or do you prefer a different kind of excess?— Mike Levy
Other than looking like a bit of badly cast concrete this has little to recommend it.
Still going strong
I would never run the stem personally even if it were free.
Syntace Megaforce 40mm/97g
Dude. Seriously. It’s made at half the speed of light.
They should have posted all strength/fatigue tests for this article.
I dig the novelty of riding something that looks like it was finished with a chainsaw, but has the strength and durability of forged steel.
Crack propagation is the first thing that came to mind for me..
Can 3D printing truly transcend this effect? If this thing came out of a casting looking like this, it would make a perfect doorstop.
1. Ti64 isn't "incredibly difficult" to machine or polish, so it raises some questions around material properties.
2. The surface finish of the un machined areas looks like it has very high porosity. Scary.
3. Id be interested to know the achieved density.
3d printing is all good, but the resulting mechanical properties are wildly vast compared to billet.
If 3D printing results in a product which takes 5x longer to make, costs 3x, doesnt offer significant improvements, and is unfinished, I'd say its not really viable yet...
If we're going to 3D print things that don't need to be 3D printed, at least go all-in and make some alien, organic thing via generative design and / or topology optimization.
Additive manufacturing has some amazing applications. This stem is not one of them.
Seriously my guess is that is corrodes horribly? Unlike alu which makes a nice protective layer of oxidization, mag will just turn to swiss cheese.
People often discuss the vibration attenuation of carbon handlebars, but the only noticeably harsh bar I've ever ridden was a particularly stiff carbon model, while the two most comfortable bars I've ridden have been the lightest carbon and lightest aluminum models I've ridden. This suggests the contribution to comfort that comes from the handlebar is primarily due to the stiffness (or lack thereof), rather than vibration attenuation.
Bar flex and stem flex have different impacts on comfort and control. A bar mostly flexes downward due to pressure from your hands, and each side is free to act independently. By contrast, movement from the stem is more from twisting, meaning both hands cannot move downward at the same time. Stem flex produces a poor balance of benefits to comfort vs detriments to control and precision. Therefore, it's best to allocate our precious grams to a less flexible stem and more flexible bar. Minimal flex in the stem minimizes the already low opportunity for vibration attenuation from the stem.
For anecdotal evidence, among the products I've tested have been a 74 g aluminum stem with a 810 mm handlebar and noticed no change in comfort (and, to the credit of the stem, only a slight detriment to control and precision), and a not-very-light road stem with enough flex to affect control and precision, yet no noticeable effect on comfort.
@st-lupo: There have been a couple magnesium stems, the most popular of which being a few generations from Easton, and a couple brands have used it for frames, as mentioned by ReformedRoadie. Corrosion was a problem with at least the first generation of Easton magnesium stems, but some versions had adequate resistance. The lowers of most suspension forks are magnesium, which are fairly reliable against corrosion.
Also, though I'm glad they did the cycle testing, and mentioned it, so we can trust its pretty damn strong, they must be using a pretty low-end manufacturing process to achieve this strength, because other SLS/SLM or EBM titanium parts come out with much nicer finishes (Atherton lugs, for one example).
-approx. half the price
-less than 100g (!)
-available in multiple lenght and both 35 and 31.8
-extensively engineered and tech details available
-made by a guy named Cornelius Kapfinger
Why pay for this then?
Agreed that i don't think 3D printing is ready for mass market consumer product but give it a few years. The advantages in terms of design and reduced material waste are huge. Like the early days of carbon parts right now in this space.
I'd say it looks like it was sand cast actually.
Tubular structures are always the best option if possible. All of these “exotic” shapes are just dumb-and expensive.
I might be mid-build on a Ti bike right now so this is extra important to me. lol
Either they are cutting corners for reasonable acceptance criteria, or don't know the nuances of controlling orientations for cantilevered surfaces and thermal dissipating media in EBAM. That part is a LONG way from having an acceptable surface finish behind the bar cradle, even for AM Ti in a recreational application.
For those who haven't had to do this in industry, if something makes the hair stand up on your neck when looking at it, you're probably correct to be suspicious.
What is the cool part about that stem if it looks bad,it is very expensive and it is not light?it is 3d printed.Yes.
That's all I need? Hold my Molson Canadian der bud...
With the UCI now into gravel - you may be aware of Rule 22.214.171.124.1 "It is not permitted to ride a component that is uglier than a glass jar full of fermented smashed bovine a*sholes"
You could get fined 50 Swiss Francs
Also lighter than the Enve carbon stem
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