Partnering with 3D printer Renishaw, the Empire Cycles MX-6 Evo was the world’s first bike made entirely from 3D-printed titanium alloy.
Spotted on a visit to Renishaw’s HQ in South Wales to see the Hope HB.T Paris – the groundbreaking track bike that propelled Team GB to seven medal wins – the 3D-printed MX-6 Evo was made in 2013 and laid the foundation for what has become one of the most important manufacturing techniques in cycling.
Renishaw and Empire worked together to optimise the brand’s MX-6 Evo’s welded tube design for 3D additive printing techniques, resulting in a claimed 33 per cent reduction in weight with no strength compromises.
This wasn’t Empire’s first bike to use innovative manufacturing techniques – the cast aluminium AP-1 downhill bike was produced back in 2007 and stood out when welded tubes were the norm and long before carbon entered the downhill racing world.
But the MX-6 Evo put the brand on the map and pushed forward 3D-printing tech in cycling.
A 3D-printed marvel ahead of its time
Using an additive manufacturing technique, the bike’s parts were created by building up layers of material on top of each other, which were ‘printed’ by Renishaw’s AM250 machine.
Initially, Renishaw and Empire agreed they’d 3D-print the bike’s seatpost mast – which is simply bolted to the rest of the bike’s frame – but after successfully trialling this section both brands agreed they’d attempt to print the whole frame.
The 3D-printing machine has a 300mm print-height limit, so the bike frame had to be printed in sections then bonded.
The frame comprises a separate head tube, top tube, shock mount, down tube and main pivot, which are bonded using Mouldlife adhesive.
For the bonding to work, the frame sections use a lugged design, where a smaller section of tubing ‘slides’ inside the next part’s bigger opening.
Quick design changes
This type of construction technique doesn’t rely on the expensive moulds used in carbon fibre, or jigs or tooling used in aluminium frame designs, so changes to the frame’s design can be made quickly and cost-effectively.
If the bike’s geometry needs updating or customising to a specific rider’s needs, this is possible without an entire re-hash of the manufacturing process.
This is an incredibly appealing prospect, and one Atherton Bikes has embraced.
Offering no fewer than 22 stock sizes for each model – plus custom geometry if you so wish – this is one of the major benefits of 3D-printing a bike frame.
Light and strong
According to Renishaw, 3D-printed titanium alloy has a higher density than aluminium alloy (4g/cm3 to 3g/cm3). On the face of it, this means 3D-printed titanium bikes will be heavier than their aluminium alloy counterparts.
In being clever with the design process and relying on the complex shapes that can be created with a 3D printer, any material not contributing to the strength of the bike can be removed, thus reducing overall weight compared to an aluminium model.
With the MX-6 Evo, Empire and Renishaw managed to shave a whopping 700g from the frame’s overall weight – from 2,100g to 1,400g – by switching from welded tubes to 3D-printed titanium.
There were no strength compromises, however.
While the MX-6 Evo was tested to and passed the EN 14766 standard (50,000 cycles of 1,200 N), the two brands wanted to push it further.
Even after testing it to six times the standard, the frame still didn’t fail, indicating the 900 MPa (megapascal) tensile strength of titanium alloy is well up to the job.
To boot, the material density of 3D-printed titanium alloy is around 99.7 per cent, which is much higher than cast metal – the construction technique Empire Cycles used previously.
Why wasn’t it a resounding success?
It’s tricky to say for certain, but we do know Empire Cycles dissolved on 22 September 2020, during the Covid-19 pandemic.
The pandemic is unlikely the reason for the demise of Empire; its last social media post was more than six years ago, although the brand’s website lives on, indicating the writing was on the wall well before 2020.
While it was never possible to buy a 3D-printed Empire, the brand’s investment in innovative construction techniques paved the way for other brands to create their own 3D-printed bikes, first with Robot Bikes, and now Atherton Bikes with the highly rated AM.130 and A.150 models.
Other manufacturers, including Pivot’s Phoenix DH bike prototype and Specialized’s prototype Demo ridden by Loïc Bruni, have used 3D-printing technology to prototype new models, so the Empire and Renishaw partnership was truly ahead of its time.
