The Vulcain Cycles Magma Isn't Another Single Pivot Steel Bike

Feb 12, 2021
by James Smurthwaite  

We first featured Vulcain Cycles in our 'Boutique European Downhill Bikes that Dare to be Different' article in 2019. The project is the brainchild of Julien Verbicaro, a former World Cup junior racer who went off to study mechanical design, started his own bike company at the age of 25 and designed and built the Magma downhill bike in Auvergne, France. Since that article, he's been testing his bike alongside a test rider and ensuring it is refined and ready for production.
Vulcain Magma Details

Intended Use: Downhill
Frame Material: Steel (aluminium rocker)
Travel: 200mm
Head Tube Angle 63.5°
Sizes: Custom (450mm reach pictured)
Weight: 16.75kg (no pedals)
More info:

Julien has been through 4 further prototype stages since we first featured his bike in 2019.

While the new version of this bike doesn't look significantly different from the one posted two years ago, there are some crucial changes that Julien has been working on to improve on his first design. The first prototype ran on 27.5" front and rear but downhill design has moved on since then and the Magma is now designed around a mullet set up. The other change comes in the materials used. The front triangle on the production bikes will be built from Reynolds 921 and the aluminium rocker has been redesigned to be lighter and stiffer.

Reynolds tubing of various shapes and sizes is the bread and butter of many a steel frame fabricator

Julien uses Reynolds 921 for the front triangle and 853 for the swingarm

The thing that first drew our attention to this bike was the fact that it wasn't simply another cookie-cutter steel single pivot that you see in a lot of steel bikes. The four-bar design remains in this bike, but it has also undergone some revisions to prepare the bike for launch. The 3D printed parts needed to get the correct shapes are now 3D printed from 15CDV6 and the lower bracket is aluminum and now bolted on to the frame so it can be changed to accommodate metric or imperial sized shocks. The final refinements came in the form of improving the tire and chain clearance and reducing the machining for complex parts.

3D printed parts finish the frame off and allow Julien to design a four-bar system.

One of the advantages of Julien's small and in-house operation is that he can design the geometry of the bike to suit each customer. Some numbers are fixed, such as a 63.5° head tube angle, 438mm chainstays and 74° seat tube angle, but the rest can be decided by the customer when they order their frame. More info on the geometry options can be found here.

The production model will have a few further changes including black anodisation on the aluminum parts and a bolted, not welded, lower shock bracket.

Julien's propensity for the raw metal aesthetic goes as far as this crankset from Hope and braided hoses.

Julien has big plans for Vulcain and won't be stopping with this downhill frame. Next up will be a 160mm enduro bike that will be closely related to the Magma but with some tweaks to the kinematic for a more efficient pedalling platform. After that Julien will be starting to bulk out his range with an all-mountain bike, a hardtail, a dirt jump bike and an eMTB. He is also pulling together some budget to try and race the Magma on the World Cup circuit with a race team.

[PCAPTION]Test rider, Tristan Bohn, has been putting the Magma through its paces and Julien has plans for a race team in future.[/PCAPTION]

Magma frames start from €3,099 and are available via a Kickstarter now for a reduced price of €2,699, here.


  • 98 0
 OMG thats a beauty for sure!
  • 18 0
  • 74 0
 "Magma" ....can't not say this word in the style of Dr Evil.
  • 53 2
 And the bike cost...? One hundred MILLION dollars.
  • 10 0
 @bigtim: it's more like the first time he says "ONE million dollars" then laughs maniacally and the UN all crease up laughing. €3000 Euros doesn't seem too OTT, 1/4 or more of it's in the shock.
  • 8 0
 Who needs swag when you've got mojo, baby! - AP
  • 11 0
 Sharks with friggin’ lasers on their heads!
  • 4 0
 "Why make trillions when we could make billions?"
  • 3 0
 and riding this bikes is like "ivana humpalot"
  • 51 0
 "The Vulcain Cycles Magma Isn't Another Single Pivot Steel Bike"...

Maybe because it's a horst link?
  • 26 0
 Yup, a Horst link bike, that rarest of breeds...
  • 5 0
 Thank you! Yes.
  • 4 0
 @FuzzyL:I wish Ironhorse came back. And Balfa...
  • 1 0
 @giantwhip: Balfa... My first real MTB. Bought used 2 step fr for 300$. Even though the bike was to small for me and everything on it was broken, I loved it.
  • 26 4
 I'm all for metal bikes and always a pleasure to see a nice steel bike instead of the all plastic ones. Just that rocker needs to be a bit more pleasing to the eye imo.
  • 7 0
 On the raw bike I think the rocker looks good. Its got a chunky, industrial aesthetic. On the painted red shot the raw rocker looks cheap to me, like the department store bikes that make it a different colour to highlight that it has Full Suspension (tm) or an older Kona or something like that. I think if it was colour matched to blend in it would look great.
  • 33 1
 @Patrick9-32: The rocker you're speaking is a prototype one, the final design is thinner and black anodized for a better look Smile
  • 4 0
 @vulcain-cycles: Nice, I bet it looks neat.
  • 1 3
 yeah, think I'll just wait for the Cascade link
  • 2 0
 I think they were going for that 'old-school Kona Stinky' chic!
  • 3 0
 @vulcain-cycles: Dang dude! I think it looks so sick in the chunky raw alloy.
  • 1 2
 @vulcain-cycles: Next time you get pics posted on PB, please make sure they get some closer pics of the welds on your frame. I like the looks of your frames here, quite beautiful, really, but I'd really like to see your welds. I'm gonna bet that they are eye-poppers, too.
  • 18 3
 *turns on megaphone* LOOKS LIKE SESSION
  • 2 2
 A rather expensive, steel version LoL
  • 1 2
 Looks like a Coal Bikes
  • 5 0
 2010 just called, they want their joke back
  • 1 0
  • 1 0
 Whispers: "Looks like a steel Gambler..."

In all seriousness, it's beautiful!

Just curious about why the lower pivot wasn't made out of a single yoke or the NDS dropout having an integrated braketab? Being 3d printed and all, it would seem cleaner and easier for production/alignment... I guess this is a prototype anywaysand trying to keep cost down.
  • 8 0
 That'a sooo sexy!!! STEEL IS REAL
  • 9 0
 So is aluminum, it just doesn't rhyme.
  • 8 0
 @southoftheborder: "Nah mate, al-you-min-ee-um is a figment of your imagination, innit?"

-the Brits
  • 4 0
 Wonderful exciting sexy job Julien. Bravo!!!
Looking forward to seeing the 160mm bike you`re working on.
I`m a steel lover - aggro hardtail junky - and thinking about a full suspension machine in a near future to replace my quite obsolete Slayer SXC.
Stanton, Cotic, Starling and so on do great bikes, but if I can get such a wonder made in Auvergne...
I`ll probably get in touch with you one of these days Wink
Cheers mec!!!
  • 4 0
 Those Reynolds tubing give the shape of the frame such a laminar flow. For those Reynolds tube numbers, I'm not surprised as they're far from turbulent.

(where my fluids people at?)
  • 2 0
 For a full suspension, I think Strouhal is more appropriate ;-)

  • 2 0
 Hey look, an engineer without the introduction of “I’m an engineer”! Wink
  • 3 0
 I tell ya what, if I had the metalworking skills and access to the equipment, I would 100% be one of these dudes making these small-runs of custom steel tubed bikes.* I love this crap for some reason. I know it isn't even at all, but I love it.

Nothing but respect for all these folks.

*OK, mine would be poorly designed, yet somehow still cookie-cutter hard-tails with questionable weld-strength that not even my family would like. And I would be surprised when I lost my shirt on the operation.
  • 7 0
 you can get a new shirt for as little as $7 so if you can't find yours it's not a huge loss.
  • 4 0
 "The front triangle on the production bikes will be built from Reynolds 921"

921 is stainless... Already decided to make that drastic of a material change without a prototype?
  • 3 0
 Stainless is a pain, prices will have to go up I suspect!
  • 2 0
 Are any of these steel frame manufacturers actually making a living off their businesses? I've never seen one on the trail, but I do live in Canada and this seems to be more of a European/British thing.
  • 4 0
 I live in Canada and ride a steel Canfield N9. Maybe you're riding in the wrong places...
  • 2 0
  • 1 3
 @Stoaks: Chromag... and?...and?... try again.
  • 1 0
 @danstonQ: Surly?
  • 1 0
 @Stoaks: Chromag doesnt weld, they contract out (to legendary welders!), and the far east.

Not really the same as Starling.
  • 1 0
 @Kainerm: Owned by the biggest p+a distro in the US. I dont think it's Surly that let's them pay the bills. Part of it for sure.
  • 1 0
 Man i would really love to own the upcoming enduroversion. @vulcain-cycles but please get a good welder. I have owned (and still do) a couple of steel fs-bikes and all were not straight or had wonky tolerances. My moxie hardtail is the first thats perfectly straight and has good tolerances, its no fs though.
  • 6 1
 beau travail ! ????
  • 5 2
 who the hell specifies a total bike weight when selling frames! That is totally irrelevant...
  • 6 0
 Naked frame weight: 4.2 kg (all screws included, model with a reach of 450mm) from their website
  • 3 0
 Has keewee chromozone vibes. For those who know.
  • 3 0
 Reynolds 921 , stainless nice.
  • 2 0
 It's pretty different from the "Final Version" drawing on Kickstarter. Might want to update that listing.
  • 3 0
  • 3 0
 Love it!
  • 3 2
 But if I can't change the head tube angle, chainstays and seat tube angle, what's interesting ....... just the size?
  • 11 3
 All the real dimensions you need that your frame suit you. Reach, Stack, Wheelbase, HeadTube, SeatTube and Fork heights.
Rest of the geometry parameters like chainstay and Headtube angle are locked to ensure a perfect behavior, in the way we have designed for it, whatever your size.
If we allow to change these parameters, we also take the risk to haves bikes that don't have a proper riding behavior between a small frame and a bigger one Wink
  • 4 2
 @vulcain-cycles: I also understand that it is complicated to change these parameters, but personally I would prefer to be able to change the angles (obviously even slightly) than reach or stack, it is more a custom-tailor bike rather than a custom-made bike. Others do it, of course it has a cost, but I believe that for an artisan producer it is an added value.
  • 4 0
 @vulcain-cycles: why are the chainstays not at least somewhat proportional to the reach? I.e. maybe have three different lengths? One of the biggest things I have noticed in the past few years of bike geo development is that personally, I find that getting the ratio of chainstay:reach dialed in is one of the key factors in a bike feeling "right"
  • 7 2
 @trialsracer: Virtual point pivot on a 4-bar linkage kinematics means at each point of the suspension, the instant pivot center change. Therefore, any change of a rear parts lengths means you will change the behavior, and the kinematics parameters, or worst ruin all the effort to get a good kinematics... And if you trust brands who say there is no problems with behavior by changing chainstays... humm may these are magicians Smile
  • 1 0
 @vulcain-cycles: well Forbidden managed it on the new Dreadnought, yes it's costly and means more work but it is possible, you just move where the pivot point on the main frame is.
  • 8 1
 @Danzzz88: It's not as simple as "you just move where the pivot point on the main frame is" unfortunately . As I said upper, on the magma DH we use a 4-bar linkage with a virtual pivot center. On the Forbidden, it's a simple high pivot that connecting the frame and the rear wheel, the path of the wheel is known and never change even the chainstay lenght become bigger or smaller.. that's why they can do it, without taking risk to change the kinematic parameters, but on a Virtual pivot center, everything is different Wink
  • 2 6
flag nouseforaname (Feb 12, 2021 at 12:16) (Below Threshold)
 Custom frame - but can't change two of the key variables for a DH bike, HA and RC. Can change WB though, by magic presumably, or just making a really unbalanced bike.
  • 1 0
 @nouseforaname: If it were as you say, there would be only one perfect geometry and all the others unbalanced, it does not seem to me that it is so, each manufacturer has his "ingredients" and each rider "cooks" them as he likes best.
  • 1 0
 @pk71: Absolutely. People can believe what they want to, and may the order books of Vulcain Cycles be ever full.

It's not like I'd buy one anyway, so my opinion is even more worthless.
  • 3 0
 Wow, beautiful frame
  • 2 0
 Gotta let a little heat out of my collar... that is one sexy rig
  • 3 0
  • 3 0
 Thats a sexy bike
  • 1 0
 That would be beautiful to just sit and look at even after you wake up after the Vulcain wallet-pinch.
  • 1 1
 I always thought steel was choice simple designs, why overcomplicate with 4 bar ? In a long run oversized bearing placement of the rear end
  • 2 0
 Hmmmm pretty!
  • 3 1
 A steel (FSR) Turner?
  • 1 0
 Propensity or predilection?
  • 2 0
 Very. Impressive.
  • 4 2
 Looks like a session
  • 5 1
 But 1,000 times more beautiful.
  • 2 2
 Not just another steel single pivot. Just another Horst Link...........meh
  • 1 1
 Why does this look exactly like the bike Isaak Levisson was building and racing?
  • 1 0
 Whatever happened to titanium frames?
  • 1 0
 I gotta admit, I’m a weld geek... this bike gets me hard!
  • 1 0
 @vulcain-cycles: 26in freeride version of the frame ? thanks.
  • 2 1
 go go go Bro'!
  • 6 7
 this must be the only bike where Cane Creek eeWings would actually look nice
  • 1 1
 Looks like a Coal Bikes (look it up)
  • 2 1
 Nice Kona Broby!
  • 1 1
 Atherton's called, you've got a litigation in the mail
  • 1 0
 Maaaaan that is nice.
  • 1 4
 Wow! Another imaginationless boring bike... What a waste of life...
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