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by James Huang
March 18, 2016
Photography by James Huang
Once solely the stuff of dreams, prototypes, and engineering experiments, metal 3D printing is finally starting to trickle into bicycles that people can actually buy. Moots and Reynolds both previewed 3D-printed dropouts at this year’s North American Handmade Bicycle Show, while two builders — Bastion Cycles and Métier Vélo — have based their entire frame designs around the technology. What once was the subject of science-fiction movies is quickly becoming reality, and an entire new world of possibilities has opened.
It still isn’t practical to build complete frames on a 3D printer. The printers are too small, for one, and there’s no advantage to using the technology for simple tubular structures that are better served by more conventional manufacturing methods. However, that hasn’t stopped Bastion Cycles and Métier Vélo from using 3D printing where it makes the most sense: at the joints.
Both companies are taking a similar approach, using 3D-printed 6/4 titanium lugs bonded to pre-formed carbon fibre tubes. The benefits are the same from either outfit: the possibility of fully custom geometry with no additional tooling costs, along with the ability to create structures that otherwise wouldn’t be possible (or practical) through forging, casting, or machining.
“Performance-wise, [3D printing] enables us to really manipulate not only the external shape of the titanium to get stiffness and strength into it, but on the inside, we’re able to manipulate the structure with things like lattice work and ribs and variable wall thicknesses to put the strength where we need it,” Bastion Cycles co-founder and managing director Ben Schultz told CyclingTips. “This means we can achieve the weight and stiffness and strength of a carbon bike, but using titanium, which, when we use it selectively at the nodes, actually creates a better ride comfort than if it were carbon fibre.”
Bastion Cycles says its 3D-printed titanium lugs allow ample design flexibility in terms of tuning ride quality.
Indeed, Bastion Cycles’ single initial model — a disc-brake equipped road bike — could easily pass for a moulded carbon composite frame, had the company chosen to cover the structure in paint. The printed titanium lugs are artfully sculpted with character lines rarely seen in metal frames and a surface finish that’s remarkably smooth for a printed part. Those lugs are then bonded to filament-wound carbon fibre tubes.
Métier Vélo, on the other hand, still highlights the lugs’ 3D-printed origins, but with shapes more reminiscent of classic steel with scalloped and pointed sleeves as well as the company’s stylised fleur-de-lis logo integrated right into the surface of each lug. While the adjoining tubes are still carbon fibre, Métier Vélo founder Jamie White has opted for roll-wrapped tubes from Rock West Composites, located nearby in South Jordan, Utah.
Lugs and logos are printed in one round. Support structures required during the printing process are removed before frame assembly. Photo: GPI Prototype & Manufacturing Services.
“[3D printing] is total design freedom,” White told CyclingTips. “This kind of approach is ideal for small custom builders because it costs the same to do one bike as ten bikes. There’s no real economy of scale.”
“One thing I’m offering is free repair or replacement,” he added. “If anything happens to the frame, I just want people to bring them back. [Repairs are] pretty easy to do. If there’s a dinged carbon tube, I can just replace the tube and if there’s any titanium damage, I can just reprint the parts. It’s a nice way to build a bike from a repair and durability perspective.”
White takes a consciously conservative approach to his frame design, using lugs that he considers “overbuilt” by supplier GPI Prototype & Manufacturing Services, with wall thicknesses ranging from 0.75mm to 1.5mm depending on location. Likewise, whereas many carbon fibre frames have paper-thin tubes you can literally squeeze between your fingers, the tubes White sources from Rock West measure a stout 1.3mm. Even the bond surface areas are three to four times what White considers to be necessary for the applied loads.
“The software package I use has some finite element analysis in it,” he said. “All of the lugs are way overbuilt. That’s one of the things I consulted with GPI about. The modelling I’ve done shows that the carbon tubes will break before the bonds or lugs give out.”
Assembling the frames is (at least in concept) and plug-and-play operation. Photo: Jamie White.
White has some destructive testing planned for later this year that will likely allow him to pare his frames down a bit, but even then, he doesn’t plan on ever catering to weight weenies.
“Because I use more more titanium and carbon than is minimally necessary, my frames probably won’t ever be much below 1,100g or so,” he said. “There’s about 400-600g of titanium, and the rest is carbon. My goal is to make tough, durable, and repairable frames that perform well. If someone wants a 550g climbing frame, I am not their builder.”
Based in Melbourne, Australia, Bastion Cycles is being far more aggressive in what it can produce, using lugs with walls as thin as 0.5mm while also incorporating ribs, cross-members, and lattice-like internal structures that it says adds measurable strength and stiffness. Claimed frame weights are impressively light, right around 1kg — a substantial 200g lighter than Métier Vélo’s. However, Bastion is more comfortable flirting a little closer with the edge of reliability thanks to a full battery of in-house ASTM durability testing, a distinct rarity amongst the hand-built crowd.
Bastion Cycles is also using 3D-printed titanium lugs and bonded carbon fibre tubes.
Bastion Cycles is also highlighting the capabilities of its flexible manufacturing techniques with an extremely clever online configuration tool that lets potential buyers customise their frame’s geometry and build kit as well as its ride quality, stiffness, and projected tire clearances — all with an instant estimate of the final frame and complete bike weights. The online tool also generates a nifty graphic that visually compares the current selection with other well-known industry benchmarks.
In either case, riding on the cutting edge of bicycle frame manufacturing technology won’t come cheap. Métier Vélo is currently selling its frames for a whopping US$8,500 with a Chris King bottom bracket and headset; Bastion Cycles’ frame is a comparative bargain at AU$7,500 including a Whisky No.9 carbon fibre fork, headset, and bottom bracket.
Moots and Reynolds also showed off 3D-printed bits at NAHBS, and while neither project is quite as ambitious as what Bastion or Métier Vélo showed off, you’re far more likely to see one of these out in the wild. Both are being printed by i2M in Birmingham, UK.
Moots is using the technology for flat-mount, thru-axle rear dropouts on its latest disc brake-equipped road, gravel, and cyclocross frames. According to company president Butch Boucher, the 3D-printed dropouts not only feature internal structures that wouldn’t otherwise be possible using more conventional manufacturing techniques, but they should also make for more consistent final products.
Moots’ new 3D-printed titanium dropout is undeniably slick.
“The thing that we were really challenged by, looking at flat mount, was that it would be asymmetric in terms of where the welding goes on the chainstay,” said Boucher. “All titanium expands and contracts when you weld it, and it also contracts more than it expands, so it’s going to move if you’re asymmetrically doing something. So here we have an opportunity to symmetrically weld — we can maintain alignment through the whole process so much better.”
“The consistency of the product is our biggest goal,” Boucher continued. “We make quite a few frames a year relative to everyone [at NAHBS]. When you’re doing onesies, you can kind of manipulate things and deal with them one at a time, [but] we need to have a consistent product from start to finish. It’s like a chef in a big, good restaurant. He’s got a crew on the line that he knows is going to create a consistent product. Part of that is what the recipe is, part of it is the ingredients, and part of it is the skill set of his crew. To have it be the same every time is the biggest challenge we face.”
Similarly, Reynolds is also using 3D metal printing to produce flat mount-compatible rear dropouts, although in this case they’ll be offered in both 6/4 titanium and steel — in both thru-axle and quick-release wheel interfaces — and they will be available to any frame builder who is interested in using them. According to Reynolds, its new 3D-printed dropouts will offer strength comparable a 2D-forged part along with drop-in compatibility with existing frame building fixtures.
Reynolds will soon be offering 3D-printed dropouts in both titanium and steel to custom builders.
Reynolds hopes to have them available to builders as soon as April or May, at a cost of around US$180-200 per pair.
Moots isn’t offering its dropouts to other companies, but Boucher says that while they’re not exactly inexpensive to make, they likely won’t add much — if any — cost to end consumers.
“If it’s not net zero, it may cost us just a little bit more. It’s not cheap but it saves us multiple steps.”
Bastion Cycles’ new road bike features 3D-printed titanium lugs and carbon fibre tubes.
The filament wound carbon fibre tubes impart a distinctive surface finish.
Haven’t heard of Bastion Cycles before? Our guess is that you’ll be hearing more about the company soon enough.
Internal routing maintains the clean look.
Bastion Cycles is going for a modern look on its titanium and carbon fibre frames.
Making rectangular-profile carbon fibre stays with sharp corners like this isn’t an easy task.
The down tube of Bastion Cycles’ new road bike is huge.
Bastion Cycles is also using a seatmast head of its own design, borrowing guts from Enve Composites.
Given Bastion Cycles’ small production volumes, it makes more sense to make this sort of thing on a 3D printer instead of investing in expensive tooling for injection moulding.
Bastion Cycles uses a 3D plastic printer to produce this clever battery and junction box holder for Di2-equipped bikes. It hides inside the seatmast and easily unscrews if you need to make any adjustments or charge the battery.
Big, rectangular-profile chainstays are matched to pencil-thin seatstays.
Bastion Cycles is using mostly round tubes on its new carbon-and-titanium road frames.
Métier Vélo is a one-man shop out of Salt Lake City, Utah that builds frames using 3D-printed titanium lugs and bonded carbon fibre tubes. Photo: Jamie White.
Smaller builders are looking to 3D printing technology for the incredible design flexibility it allows. Photo: Jamie White.
Métier Vélo prints the rear brake mount from 6/4 titanium and bonds it around the carbon fibre stays. Photo: Jamie White.
Métier Vélo builder Jamie White says there is “3-4 times” the amount of bond surface area that he feels is actually necessary. Photo: Jamie White.
Currently, frames are built with integrated seatmasts using a topper of Métier Vélo’s own design. Photo: Jamie White.
Lugs come out of the printer with a satin finish. Photo: GPI Prototype & Manufacturing Services.
The titanium down tube logo is a nice touch, as are the printed-in logos around the seatmast topper’s height adjustment collar. Photo: Jamie White.
Unlike forging or casting, 3D printing doesn’t require lots of heavy-duty industrial equipment; just the printer. Photo: Jamie White.
Surface finish is pretty good straight out of the printer.
Moots says the biggest issue with trying to weld flat mount tabs on to a dropout is maintaining proper frame alignment. With 3D-printing, however, it’s not an issue.
It’d be impossible to build internal structures like this into a metal dropout using any other method but it’s easy to do with 3D printing.
This should make feeling cables and wires through the chainstay a lot easier.
A cutaway of Moots’ new dropout shows the integrated internal cable routing guide.
Moots showcased its new 3D-printed titanium disc dropouts on this gorgeous road bike at NAHBS.
The new flat mount standard for disc callipers is indeed cleaner looking than the post mount interface, which was adapted from mountain bikes.
There’s plenty of clearance for the rotor.
Moots intentionally designed its new 3D-printed dropouts to integrate nearly seamlessly with the rest of the frame.
Moots’ new 3D-printed titanium dropouts will be available on frames soon.
Welding or brazing on the posts for the new flat-mount disc calliper standard would normally affect the frame alignment but that isn’t an issue with Reynolds’ new printed dropouts, where the holes are built right in.
Reynolds’ new printed steel dropouts look particularly elegant.
Internal ribs add extra strength in a critical area.
A cutaway of Reynolds’ new 3D-printed titanium dropout.
Internal routing is designed right into the dropout – something that wouldn’t normally be possible on a dropout built using more conventional methods.
Ti Cycles incorporated Reynolds’ new printed titanium dropouts into this beautiful gravel/all-road bike at NAHBS.
Ti Cycles has customised this Reynolds dropout with an extra extension for the Shimano Di2 wire. Internal routing is already built right into the dropout’s design, though.
The Reynolds 3D-printed titanium dropout is intentionally left rough here but there’s no reason why it couldn’t be finished to match the rest of the frame.
Reynolds’ dropouts can also be customised with things like fender and rack mounts as shown here.
There’s just something about a proper head tube badge.
Ti Cycles showed off some neat frame finishing techniques at NAHBS.