Bastion Cycles Road Disc frameset review

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Bastion is a new Australian custom framebuilding company founded and operated by a trio of engineers set adrift by the collapse of the local automotive industry. Working with a combination of carbon fibre tubing and 3D-printed titanium lugs, Bastion engineers each frame to meet the needs and desires of its customer.

Our Australian tech editor, Matt Wikstrom, recently spent a few weeks riding one of Bastion’s road disc bikes to learn what the new brand has to offer.


How many car engineers does it take to design a new bike? The answer for Bastion is three: Ben Schultz, James Woolcock and Dean McGeary.

All three had been working in Toyota’s Technical Centre in Melbourne in 2014 when the company announced it would be closing the facility by mid-2016. Over 100 engineers would be losing their jobs, but it wasn’t just Toyota that was having problems. The death knell had been sounded for the entire Australian car industry and Ben, James and Dean had a decision to make.

To many, starting a high-end custom framebuilding business might seem an unconventional direction, perhaps even foolhardy, but the three men spent five months conducting a feasibility study before pushing in their chips.

Framebuilders are typically seen as craftsmen and there is a large measure of mystique surrounding the pursuit. Tradition and experience counts for a lot and budding craftsmen normally serve a lengthy apprenticeship under a suitable master before they hang out a shingle.

The men behind Bastion aren’t craftsmen, though, they’re engineers. Trained to understand the capabilities and limitations of any building material, Ben, James and Dean have spent their professional lives “crafting” all sorts of products. Coming from an industry that has very high standards for safety and performance, they weren’t lacking confidence when launching the new venture.

“I think more than confidence we had passion and drive to really do something great,” explained Ben. “We were actually really nervous, but I think we were more afraid of not trying. I’m fairly confident though that Bastion would not have happened if the automotive industry had not shut down in Australia.”

Engineering upstarts

Bastion was founded in March 2015 and the company unveiled its first metal prototype at the Melbourne Custom Bicycle Show a few months later. Compared to the welded and brazed creations populating the rest of the show, the bonded carbon fibre frame with 3D-printed titanium lugs was quite a novelty and attracted a lot of attention.

Ignore the materials and Bastion’s construction strategy is very traditional. Time-honoured, as the cliché goes, yet the result is at once refreshing and familiar. By embracing additive manufacturing to create the lugs, Bastion was able to bypass the limitations of conventional lugs to create frames with a wider range of geometries.

Furthermore, 3D-printing provided an opportunity for additional engineering that the men behind Bastion were excited to embrace. When combined with the opportunities that composites provide for tuning the characteristics of the frame, Bastion’s bonded frame easily upholds, and arguably extends, the principles of custom framebuilding.

Two years on and Bastion is well into the swing of things. Dozens of orders have been placed and Ben, James, and Dean are deriving enormous delight from sharing and building their bikes for passionate cyclists. Their sales pitch is a simple one — to help the customer create the perfect bike — while their approach is remarkably sophisticated.

A simple yet diligent approach

At face value, Bastion’s road disc frame comes together in a very simple manner: a collection of carbon fibre tubes is bonded to titanium alloy lugs to create the final product. While the theory behind this strategy is very easy to understand, the execution is very demanding since each joint requires an exacting fit otherwise it will fail with use.

All frame assembly takes place in Bastion’s workshop in Melbourne, Australia where Ben and James are in full-time attendance. While it is common to talk about the millimetre-perfect construction of a custom-built frame, James and Ben work at a level that is two orders higher, taking notice of hundredths-of-a-millimetre.

The carbon fibre tubing is filament wound rather than hand laminated. A continuous length of resin-soaked tow is wound onto a mandrel under tension and the control of a computer to create each length of wound tubing. It’s a process that is incredibly consistent and far more reproducible than hand lamination, but most importantly, it is not prone to wrinkles and voids. A Sydney firm manufactures all of the main tubes and the seatstays while Bastion winds the chainstays in-house.

Manufacture of the titanium alloy lugs is also outsourced, this time to a New Zealand company with over a decade of experience in additive manufacturing. To say that the lugs are 3D-printed is a simplification though, since they bear no resemblance to the plastic printed parts that have come to exemplify the technology. A very specific process referred to as selective laser melting (SLM) is used to create the lugs where the particles are basically welded together to create a non-porous and essentially homogenous product.

Bastion takes care of all of the technical details for each lug, specifying the materials, shape, thickness, internal latticing, and print orientation. Destructive sample pieces are included in every run for quality control; if the tensile strength of these parts fails to meet expectations, the entire run is scrapped.

While Bastion has a good understanding of its printed parts, the company is far from complacent. It has conducted hundreds of hours of empirical testing to prove the impact strength and fatigue resistance of the frames while logging over 50,000km on a collection of nine prototype frames. Nevertheless, James acknowledges there is more to learn:

“The general material properties meet or exceed the ASTM standards for Ti6Al4V (Grade 5) titanium alloy. However, the fatigue properties of laser-melted metals, and in particular the thin-walled, latticed titanium structures that we use is still a developing field of research,” he says. “We are currently supervising a research project in collaboration with Monash University to characterise the stiffness and fatigue properties of these novel structures. This research will enhance our ability to simulate the fatigue life of a component without building physical samples, enabling us to innovate even further on future developments.”

The company has also learnt how to contend with some of the limitations of the technology. At the outset, Bastion was hopeful that they could satisfy the stringent demands for an EVO386 bottom bracket shell and an integrated headset with the raw printed lugs, but there was too much variation. As a result, the head tube and bottom bracket parts are machined in-house to exacting tolerances to ensure the best fit for these parts.

The magical blend of titanium and carbon fibre

Bastion is not the first bespoke framebuilder to combine carbon fibre tubing with titanium lugs. Proponents for the combination such as Seven, Firefly, and less recently, Lemond, have argued there is magic in the blend, and for Bastion, they see the benefit in terms of damping.

“The ride characteristics are primarily dictated by the tubing, and by tuning the carbon fibre layup — particularly in the “top half” of the bike — vertical compliance can be introduced to improve ride comfort,” Dean says. “The titanium lugs are used to stiffly join the carbon tubes so that deflections in the tubes are promoted. However, the titanium lugs do this without transmitting the high frequency road buzz typically associated with a full carbon fibre frame due to titanium’s low internal damping.

“So whilst they are not a tuning element, they do provide a smoothness to the ride quality that isn’t found in a full carbon fibre frame.”

The modular nature of Bastion’s frame construction makes it relatively easy to tune the bike to the customer’s needs. The company has developed three levels of stiffness for its frames, depending on the stiffness of some or all of the carbon tubes.

“Regular (R) is our base level,” Dean explains. “For Stiff (S) we increase the stiffness of the down tube and chain stays, which increases torsional stiffness significantly with almost no decrease in vertical compliance and comfort. For Extra Stiff (X), we increase the stiffness of every tube in the frame, which achieves a further increase in torsional stiffness, but comes with a noticeable decrease in vertical compliance and comfort.”

Bastion has a testing rig for measuring the stiffness and compliance of every frame it builds and goes so far as reporting the values when presenting the final product to the customer. It’s a process that serves to validate Bastion’s predictions for the performance of the frameset as much as it helps with quality control.

Purposeful design choices

One benefit that comes with Bastion’s bonded frames is that repairs are generally quick and affordable. The company keeps a stock of all carbon tubes and archives the print file for every customer, so either component can be readily replaced at short notice.

Replaceable rear derailleur hangers have become a common, if not expected, feature for any modern frame. In the context of an all-carbon frame, a sacrificial hanger makes a lot of sense, however it comes with a significant compromise since alloy hangers aren’t especially stiff.

Bastion made use of a replaceable alloy hanger for its first prototype but abandoned the idea for the simplicity and superior performance of an integrated hanger.

“Considering that one of the major advantages in additive manufacturing is the ability to integrate components, saving mass, eliminating fasteners (screws) and processes (tapping), we judged to print the hanger portion as part of the dropout,” explains James. “It didn’t sit well with us that the bike should have a component that is deliberately designed to break.”

Portions of the hanger are actually hollow with three internal ribs added to increase the stiffness of the part. As a result, the hanger is lighter yet almost two times stiffer than a replaceable alloy hanger. Nevertheless, Bastion understands that some riders may prefer a sacrificial dropout and offers it as a no-cost option.

The same level of attention is applied to the rest of the printed lugs. The printing process allows Bastion to remove material from within the lug that could never be accessed by conventional tools. At the same time, lattices, ribs and other structures can be introduced to strengthen very specific regions of the each lug. It is also a simple matter to create channels for the internal routing of cables, wires and/or hoses.

The final weight for Bastion’s road disc frames hover around 1kg, depending on size. That has to be counted as very respectable given the frame has an integrated seatpost and the saddle clamp is included in the final weight. With a judicious (and pricey!) selection of parts, Bastion can put together a sub-6.8kg bike.

Bringing a new bike to life

Ordering a frameset or bike from Bastion normally starts with a conversation and progresses in a series of steps as each part of the build is decided until the customer approves the final blueprint. It’s a process that normally takes 3-4 weeks then another 6-8 weeks is required to build and finish the frameset or bike.

There is no strict need for the customer to visit the Bastion factory in Melbourne — the company currently has retail partners in the USA, UK, Canada, Singapore and Korea — but for those that do, they will be taken on a tour of the workshop and will get to ride a demo bike. The latter will appease any buyer that has reservations about what they can expect from the bike, though the demo bikes serve only as a rough sketch for the final product.

While Bastion has supreme command of the engineering of its frames, the company leaves the rider’s fit to experienced professionals, such as Stewart Morton at riderfit in Melbourne. While the company has come to trust Morton’s work, customers are free to supply data from any fitter.

Bastion has conducted a couple of fitting tours in recent months, travelling to the Tour Down Under in Adelaide in January, and then Sydney in April. With a fleet of demo bikes on hand and Stewart Morton ready to measure, these tours succeeded in securing new orders as well as generating publicity for the brand. As such, the company has plans to expand the program, at least within Australia.

For those customers that would rather take a hands-on approach, Bastion has a DIY option where they can use an online tool to design and order the frameset or bike. A live blueprint is coupled with a series of menus that allows the user to stipulate each aspect of the geometry and build. It’s a powerful tool but the geometry is presented solely in terms of stack and reach, so I had trouble relating that to my numbers for saddle setback and handlebar drop.

Bastion’s website provides the tools for designing and visualising its framesets with a pair of plots for judging the stiffness/compliance and steering/responsiveness.

Empowering customers with information

Framebuilders typically rely on language to describe the traits of their bikes, adding some romance to the process but also leaving room for ambiguity. Bastion prefers a quantitative approach, making use of direct measures for torsional stiffness and vertical compliance to demonstrate how the proposed bike will compare with other brands and models.

They do the same for the handling of the bike by comparing steering (slow versus fast) with responsiveness (agile versus stable). The latter takes into consideration the length of the stays and the height of the bottom bracket, and once again, the proposed bike is compared to a variety of other brands and models. Amidst the range of possibilities, Bastion has identified a “recommended zone” — agile bikes with slower steering — that it uses as the target for all of its designs.

For those working with Bastion’s online design tool, these plots form part of the display and are automatically updated with every change that is made to the geometry of the bike. It’s a powerful metric that allows the DIYer to visualise the impact of their design choices. And for all customers, the plots serve to remove a lot of the ambiguity that can cloud communication between the framebuilder and the customer.

Needless to say, Bastion has a deep understanding of frame geometry. What I found most impressive was their command of the topic in terms of the whole bike and the rider. “Rather than consider individual parameters in isolation we consider the impact of geometry choices on the overall handling of the bike,” James said.

“Whilst it is the customer’s final decision, we tend to prefer a longer chainstay length (415mm+) allowing larger tyres, a larger BB drop, and a head tube angle and fork rake that deliver handling characteristics in the centre of our recommended zone. A lot of builders simply try to achieve a certain trail, but our research has shown that looking at trail alone is not enough.”

In discussing the design and geometry of its frames, the men at Bastion were refreshingly open. They were always willing to expand on the reasoning behind their preferences, and if relevant, share data in support of an assertion. It makes for a lot of detail, and while I reveled in it, there’s a chance that some buyers may find it overwhelming.

The final engineering report that is generated at the end of the design phase is dense with detail but the language is inviting and it takes the form of a proposal rather than any kind of dictum. It makes for an impressive presentation that comprises a blueprint for the frameset, a 3D-file, and a considered discussion on all of the bike’s promised characteristics.

With this report, the customer has a very clear, and indelible, picture of what they can expect from Bastion. I can’t think of another framebuilder that makes the same kind of effort and I suspect it may usher in new expectations for the consumer.

The final product

The presentation and finish of Bastion’s framesets is just as unique as the rest of its offerings. I found the geometric weave of the carbon tubing captivating while the raw titanium lugs added a bold, industrial edge to the bike. Bastion’s distinct branding ensures the bike won’t be confused with any other but I don’t expect the stark and austere styling will appeal to all riders.

The range of finish options starts with a choice of colours for the logos on the bike, a few bands of colour, and a choice of clear coats for the carbon tubing. The raw lugs are sandblasted and polished for a smooth finish while the rear dropouts can be etched with a variety of personal touches including the owner’s name. There is room, of course, to go beyond these options with a full custom finish but it will add to the final cost of the frameset.

All of the painting is done in-house at Bastion’s Melbourne workshop where the amount of care and diligence applied threatens to rival the engineering effort. It’s a labour-intensive process but the men at Bastion understand that any appreciation for the effort they’ve made to create the bike often hinges on the final dress layer.

If it’s not clear at this point that Bastion’s framesets are a high-end product, then the pricing should settle the issue. At present, the price for a road or road disc frameset with DIY geometry is AUD$7,750 (excluding GST) (~US$5,735/£4,445) while buyers that leave the frame design in the hands of Bastion can expect to pay AUD$8,750 (excluding GST) (~US$6,475/£5,020). Complete bikes are also available, where prices start at around AUD$13,000 (excluding GST) (~US$9,620/7,450) for an Ultegra Di2 build.

Out on the road

There is a certain futility in reviewing a frameset from a bespoke framebuilder. Given all of the options on offer and the way that Bastion tunes each bike to suit the needs of each customer, there’s only so far any impressions for a sample bike will go. Be that as it may, after riding one of Bastion’s demo bikes for a few weeks, I’m impressed with what the company has to offer.

The bike in question was dubbed “Alpha-03”, an early prototype in Bastion’s demo fleet. Sporting an Ultegra Di2 groupset, Shimano’s road disc brakes and a set of carbon clinchers from Curve Cycling, the bike weighed 7.46kg without cages or pedals.

According to Bastion’s metrics for Alpha-03, the bike was agile with slow steering while its stiffness and compliance were both in the middle of the range of possibilities. That’s pretty much what I experienced too.

Looking back on my time on the bike, I now see that I learnt everything that there was to know during my first ride on the bike. I was in Melbourne at the time and James and Ben were leading me along the banks of the Yarra River on a glorious spring day.

We were headed for Yarra Boulevard in Kew, an iconic stretch of road where inner-city cyclists can be found any time of the day. By the time we arrived there, Alpha-03 had already proven itself to be a capable performer. The bike was stiff enough to serve my purposes, reasonably responsive, and there was enough compliance to smooth out rough road surfaces. All told, it was a pleasing blend of traits.

The integrated carbon seatpost reminded me of Scott’s Addict and Canyon’s Ultimate CF SLX in that there was some flex that could be both seen and felt, yet the saddle never felt unstable, and I never experienced a bobbing sensation. There remained, however, an obvious rigidity to the bike that could be improved upon for those looking for more comfort.

As ready as Bastion’s Alpha-03 was to accelerate, it wasn’t about to challenge the really potent bikes I’ve ridden, such as Storck’s Aernario or Canyon’s Aeroad. Such comparisons really aren’t fair though since Alpha-03 was weighed down by a first generation road disc groupset and the bike was a little large for me. The handlebars also happened to be considerably wider than what I’d choose to use, which only enhanced the sense that I was trying to ride a bike that was too big for me.

I had to compensate for the size of Alpha-03 with a short inverted stem, and that undermined the steering somewhat, adding some twitchiness to the bike. It didn’t ruin the handling, but it was another compromise that prevented me from truly connecting with Alpha-03.

As I spent more time on the bike, I came to cherish its ride quality. This is a trait that Bastion has yet to develop a metric for, but the company is convinced that it is quite unique to the blend of materials they use. It also happens to be a quality that is very difficult to capture given the constraints of written communication.

It was something that I quickly discovered during my first ride on Alpha-03 in Melbourne, and while it could be fleeting, it wasn’t difficult to rediscover from one ride to the next. In some ways, it reminded me of a highly refined titanium bike such as Baum’s Corretto, and at other times it resembled a great composite frame, like Canyon’s Ultimate CF SLX.

If Alpha-03 was a musical instrument, then I could refer to the ride quality in terms of tone. A minor nuance, to be sure, but it makes for an appreciable difference, at least for the connoisseur. In general terms, it does little to elevate the performance of the bike but it does add to one’s enjoyment. So while I had trouble connecting with Alpha-03 on the basis of fit, there was something sublime in the nature of its ride that was almost irresistible.

At the end of the review period, Bastion forwarded the engineering report for what they considered would be the ideal build for me. The frame was smaller than the Alpha-03 with a shorter, lower top tube that left more of the seatpost exposed. This would add considerably to the vertical compliance of the bike while the “S” tubeset would be used to increase the torsional stiffness of the bike. There was also a change in the geometry of the front end to mirror that of my Baum Corretto.

I found all of these changes immediately compelling, and I couldn’t help but consider the finish options with a fresh eye while running through the components I’d choose for the build. Alpha-03 wasn’t the perfect bike for me, but I was convinced that Bastion would be able to build it for me.

Summary and final thoughts

Bastion’s bespoke framesets are clearly a product of the new millennium, harnessing some cutting edge technology to create a unique bike that can be carefully tuned to suit the needs and desires of the customer. The result is a high-end product with the kind of high-end price that will horrify pragmatists, but then, a bespoke frameset is not usually a pragmatic choice.

Bastion strongly believes there is enormous merit in combining carbon tubing with printed titanium lugs, and based on my experience with Alpha-03, I must agree. Indeed, I find myself marvelling at what a trio of automotive engineers have been able to achieve in a very short period of time.

The bike is impressive, but so too is the company’s approach. Bastion’s mission is to empower its customers by providing the kind of information that they can use to better direct the design of their new bike. For the uninitiated, this may prove a little overwhelming, but overall, I think the company achieves this easily and may be setting a new standard for bespoke framebuilding.

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