A Closer Look at the Production Privee CNC'd Downhill Bike
In January, Production Privee broke the news on the team change that nobody saw coming. As a company that primarily specialized in steel hardtails, it came as a great surprise to see them unveil a CNC'd aluminum downhill bike for Alex Marin and the Brigade downhill team.
Although Production Privee's name is the one primarily attached to the bike, it was actually created in partnership with Forestal Bikes. Forestal is another Andorran brand and they own a production facility in the small principality. The two brands announced they would be working closely together in March 2020 with the aim of creating "bikes that break the mold". We saw the first fruits of their endeavours with Pavel Alekhin's custom titanium dirt jump bike unveiled in December last year.
From what we can tell, Forestal will continue working on its upcoming eMTB, while Production Privee will make handmade and unique frames from the same factory. This downhill bike is primarily an R&D exercise for the brand and the first step on a path that should eventually allow them to, "design, engineer and manufacture [a bike] in quite short notice". Although Cedric Gracia is involved with the Forestal Group for testing purposes, it's the Brigade Team that will be taking the lead on this project.
The Construction
This downhill bike has been a surprisingly quick project to pull together for Production Privee. In-house manufacturing apparently meant that after the design team scribbled for a month, the engineering and machining stage of the project took just three months and then the bike was ready. Production Privee admit that a large part of this project is R&D for future projects and say that the advantages of using CNC production are " the freedom of shaping, thickness management... the ability to modify design, geometry, structural, kinematics parameters quiet fast."
This isn't the first time we've seen a CNC'd downhill bike. Most recently, Isak Leivsson was testing a 200mm version of Pole's Machine that could well have been the longest World Cup downhill bike ever. There is a key difference between Isak's Pole and the Production Privee's bike though. While both bikes are milled from aluminium in 2 separate sections, the Pole bike is glued whereas the Production Privee is welded.
There are quite a few machined-in flourishes, including these swirls on the downtube. and an integrated seat clamp
At the moment, Production Privee is keeping any geometry or other numbers close to its chest although they will tell us that each bike will be tailored to the needs of its rider.
Suspension
The suspension system is based on Forestal's Twin Levity system. This is a linkage driven single pivot that has been adapted from the Forestal Syrion eMTB, although Production Privee have played around with the leverage ratios and travel to suit it to downhill. Apparently the brand would have been willing to go back to the drawing board if the Brigade riders weren't happy about the performance, but the first reviews from Alex and the rest of the team have been enthusiastic, so it's the system the team will be sticking with.
What's next for Production Privee & Forestal?
From what Damien Nosella, founder of Production Privee, will tell us, this bike is more of an R&D project than a serious commercial proposal, although the brand has said a production version could be available by 2022.. He said, "using alloy is part of deeper R&D program we’re carrying. As we are starting our production facility with the targets of setting up new manufacturing processes, being able to CNC and weld alloy are a small part of what we need to achieve... It’s more a milestone needed to be achieved leading to new stuff that we will implement during the year." Damien has also told us that he hasn't yet fully turned his back on steel and that only parts of any future chassis will use CNC'd aluminium.
Reading between the lines, we're expecting Production Privee to combine new school and old school production techniques in a similar fashion to Actofive's very impressive P-Train that was released in May last year. There's no timeline on any future projects yet but what better place to test a new direction than in the furnace of World Cup downhill? We'll be watching the Brigade team very closely to see how their new frame gets on.
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Less clear on the advantages over just welding some aluminum tubes together though.
why carbon fiber molds are too expensive?
Making traditional tubular frames requires that you either use off-the-shelf tubes, or pay for the tooling to draw and hydroform custom ones. By contrast, aluminum welding and CNC machining are two very well understood and easy to control processes that require no special tooling. It also gives engineers ultimate freedom over wall thickness and tubing sizes.
Bonding aluminum, like in the Pole Machine, is strong, but the process is hard to control perfectly, and the end result has a finite lifetime. Welding, on the other hand, is even stronger and lasts for the life of the base material (given proper post-heat treatment).
They're getting dialed on their CNC equipment so they can start producing molds. And they're figuring out geo so when they do make molds, they make it right.
It's clearly not the same thing nor the same job
For this CNC’d frame from an environmental perspective, metal is better than carbon, because carbon is just reinforced plastic. Aluminium is very easy to recycle.
The real cost savings for aluminum vs carbon happens once you go into production. The materials and labor are just cheaper. Even with CNC you can see the PP has forged links and dropouts. But otherwise it's just three processes, mill 2 halves, weld, and assemble.
Carbon fiber bikes are more expensive because of the cost of the mold (which must be cnc machined) even if less resistance is required to this mold compared to forging, so maybe no’s that much expensive
Also this is a difficult material to work and requires to be worked by hands to do the junctions between the two sides of the frame
For metals , most of the times , pipes are made by rolling , which creates a better mechanical characteristics as the fibers of the metal are concentrated, while when you machine with CNC on a big bloc , you just cut the fibers.
Also CNC involves most of the times lots of waste as most of the material from the original block is machined , and can generate costs
Forging is the manufacturing process that gives the best mechanical properties as it keeps all the material fibers , so basically , for instance for a pair of pedals , CNC doesn’t mean anything, and it would be ridiculous to prefer it over forged pedals
That’s the thing though, finding high quality carbon in the bike industry is like finding chicken teeth. Take most carbon frames to Mclaren or someone like that and they’d just laugh at you. It’s the lowest possible grade of carbon built cheaply in China and that’s why it performs so badly compared to alloy at least with alloy you’re getting premium materials. I’m sure carbon done correctly could outperform alloy if you spend enough money but we’re not seeing that currently with these cheap carbon frames.
That being said, the raw materials are pretty much the same. The difference comes down to manufacturing controls and tolerances, where the bike industry is woefully behind aerospace (perhaps understandably) and likely behind automotive (any auto engineers out there wanna comment?).
@emptybe-er: Very true; but, ugly beads are one thing. Im fine with that. If your not getting proper penetration like on the back end of that top tube, take it back to the kitchen.
This is a boutique race frame! Cmon. I have CC students that could call that out.
Immaculate welds are a waste of time and resources on a project like this; if it was a production prototype to show off I’m sure the welding would be more aesthetically pleasing.
I'll see myself out.
Quit using an apostrophe where an "e" would do just fine. Past-tense of "CNC" is "CNCed". Apostrophes are for contractions and possessives.
Same with "spec'd" or the even worse "specc'd": it's "specced" or even just "specified"; or maybe "equipped" is better, until you guys turn it into "equip'd"...
I'm surprised these bigger outfits aren't using AM junctions with welded tubes like what Sturdy cycles and Huhn cycles are doing: so much more accurate and significantly less wasteful both in energy and material terms (never will machining a whole frame out of a billet of virgin aluminium ever be considered environmentally friendly, probably not even compared to carbon moulded frames).
But if you want to replicate the look of a carbon monocoque frame in aluminium for a prototype without investing in stamping tools I guess this fits the bill-et.
Neither make any sense for any kind of volume and with DMLS/AM Metal / what ever you want to call it, if you can make it any other way, then you should - from a cost prospective. Only place for DMLS is producing parts which cannot be made any other way
I'm expecting some backlash here...
Looks like a stump jumper!
LOOKS LIKE A SESSION!! Wooooooo
Ah there we go!
It's also on all the DH bikes shown, not just the first picture.