The history of Arevo sounds too good to be true: The Californian start-up is based in the heart of Silicon Valley, in the neighbourhood of tech giants Facebook and Apple, and is aiming to become a global player with its futuristic carbon bike. Superstrata revolutionise the bicycle market. The highlight behind the bike - which is available as a normal bike and an e-bike version - is the revolutionary manufacturing process. The frame without a seat tube is made from a thermoplastic reinforced with carbon fibres and is 3D printed by a robot. To this end, the start-up launched a Crowdfunding campaign on Indiegogo and has been successfully raising capital ever since. To date, Arevo has collected almost five million euros from Superstrata customers through this campaign. An incredible sum for a bicycle start-up! Especially in view of the fact that the Superstrata still seems to be a long way from being ready for series production. Because apart from full-bodied promo videos on half-finished prototype bikes, computer-generated graphics and promises, there is no proof that the Superstrata is ready. However, Indiegogo states that the first buyers should receive their bikes by the end of 2020. Superstrata has since responded to our BIKE enquiry about the current status of the bike and answered our interview request. You can read the update below. However, former Olympic track sprint athlete Sky Christopherson, who makes a statement in the promo video, did not respond to our enquiry.
A frame design without a seat tube and stiff at the same time?
Arevo's method, developed for aircraft construction, enables complex shapes and almost any conceivable geometry. The developers promise carbon frames in a single piece, in a fully automated process with consistently high industrial standards. According to Arevo, the first Superstrata frames are to be printed in the USA, but production is also planned in Vietnam and Japan. This means that one of the huge 3D printers, which cost around 800,000 to 1.1 million euros each, will be needed everywhere. The frame weight is said to be 1300 grams. But above all, the special frame design without a seat tube - which Magdeburg's forge Urwahn with his city fox made of steel - leaves experienced bicycle developers and engineers in doubt. "I have been following the development of carbon production methods very closely for years. 3D printing in particular still has great potential for the future. In my opinion, however, it is still too early for a complete bicycle frame. In terms of quality, weight and stiffness, a 3D-printed frame cannot keep up with current high-end carbon frames," says Dipl.-Ing. Christian Gemperlein, head of Bike Ahead Composites.
3D printing in bicycle construction
While only certain frame components come out of the printer on the Robot or Atherton bikes, Californian manufacturer Arevo is demonstrating a fascinating and much more complex approach to 3D printing carbon fibre. A robot equipped with a laser glues hair-thin carbon fibres on top of each other in a fully automated process and in almost any shape. For the bicycle industry, this would be a completely new alternative to the usual manufacturing process in Asia, where carbon frames are largely produced by hand and in many small steps. Today, high-end carbon frames consist of up to 400 small pieces of fibre fabric, which workers have to place one after the other at precise angles and with millimetre accuracy on a mould. For comparison: on the Urwahn bike, only the connecting pieces such as the head tube, bottom bracket and dropouts are built up layer by layer from previously atomised, high-strength steel using a 3D printer. These are then reworked by hand and soldered to CrMo steel tubes.
Arevo gained its first experience in bicycle construction with the Emery ONE collected. However, this e-bike with a 3D-printed frame from Arevo has not made it beyond small series production. The Superstrata could have a similar fate. It's a long way from chic CAD graphics to a high-quality product ready for series production, as Rotwild head designer Lutz Scheffer knows: "The Superstrata was also a topic of discussion at our company. My conclusion: in this production method, the frame will never pass any DIN or DIN Plus test. When I see how we have to handle the high-strength fluorocarbon in order to pass a Zedler test, for example. I don't think the company can bring this bike onto the market. Unless the box is solid material. But then the frame weighs at least ten kilos."
Crowdfunding - shopping with risks
Crowdfunding platforms offer the opportunity to realise innovative products or ideas with the help of swarm financing. There are several platforms here - the best known are "Kickstarter" and "Indiegogo". The campaign for the Superstrata bike is also running on the latter.
The "Indiegogo" platform has already made negative headlines. In contrast to the Kickstarter platform, campaigns are not scrutinised. The company "Trustpilot" checks the trustworthiness of internet platforms. Their assessment of the crowdfunding platform "Indiegogo": Unsatisfactory! The Kickstarter platform receives a similarly poor rating. On the comments bar of Trustpilot.com you can read experiences from users such as: "Beware of scams!", or "Indiegogo is ideal for scammers", or "Beware of scams. Money gone. Credit card company won't refund money." According to Computerwoche.de four per cent fee is charged to the campaign initiator - if the funding target is not reached, as much as nine per cent is paid to the crowdfunding platform.
What can I do if I have participated in the project?
Refunds from users are generally difficult. According to Computerwoche.de, Indiegogo refuses to take action itself. However, there are exceptions. For example, if the investment amount has not yet been paid out to the campaign initiator or the term of the campaign has not yet ended.
Anyone who wants to withdraw their money due to the allegations should act quickly now. The campaign runs until 15 September 2020, after which, according to Computerwoche.de, the chances of getting a refund are rather slim.
Peter Denk: "Torsional strength of a PE bottle."
BIKE: Peter, you think the Superstrata campaign on Indiegogo is a scam. What makes you think that?
Peter Denk: When things sound too good to be true, they often aren't true. A sensational design without a seat tube, which the bike industry has already tried umpteen times without success, combined with a revolutionary-sounding but unsuitable manufacturing process for bicycle frames, combined with technically soft thermoplastic carbon, which has already driven GT and Centurion to the brink of ruin, combined with an incredibly low price, combined with performance data that even we, as long-standing carbon world champions, could not achieve with the best materials. And all this with a 50 per cent discount if you pay immediately. And delivery is scheduled for the end of 2020, i.e. in 4 months.
You don't think the project is technically feasible. What exactly do you doubt?
It is impossible to produce a completely thin-walled tube using the manufacturing process shown. As soon as the robot reaches a vertical position, it would have to place fibres at an angle on a 0.8 millimetre thick wall, cut them off and fuse them together. Even if this were technically possible, it would result in a mixture of nylon and super-short carbon fibres, which would perform extremely poorly. Bicycle tubes must be held together at a 45-degree angle by circumferential fibres. Otherwise, they simply flake open under the slightest torsional forces. The manufacturing process shown makes it impossible to place circumferential fibres. The torsional strength is probably at the level of a PE bottle, which is completely inadequate for the loads on the bike. The chosen design without a seat tube leads to extreme loads. This includes extreme torsional stress on the down tube. In addition, carbon reinforced thermoplastics melted in layers do not have a smooth surface due to the system. It is therefore extremely difficult, if not impossible, to sand the surface of such a frame smooth and apply the paint finish shown.
A promo video is shown on Indiegogo. It appears to show a ride on an unfinished prototype. What does the video tell you? What conclusions do you draw?
The design without a seat tube tends to collapse when pressure is applied to the saddle. In the videos, the bike is usually pushed or carefully ridden standing up. The seated riding shots were taken with a frame with a seat tube. In my opinion, this is a classic 3D-printed frame, which was then covered in carbon and painted by hand. A pure show specimen. I think the statement that there is a real prototype bike that works is a lie. In my opinion, this is a deliberate rip-off by a few freaks from Silicon Valley at the expense of the bike scene. I think it's particularly unfortunate that this will hurt the truly innovative, small forges in terms of funding in the future.
Update, 14.9.2020
Superstrata responded to our article and answered our enquiry, which we had already sent to the US start-up in advance. The crowdfunding campaign on Indiegogo has now raised almost 5.5 million euros.
BIKE: Experienced German bike developers such as Peter Denk and Lutz Scheffer claim that the Superstrata bike would be impossible to realise. For example, achieving thin wall thicknesses and a rigid frame with the 3D printing process presented. What do you think?
Superstrata: We will not produce the Superstrata like traditional carbon bikes. This process is very expensive due to a lot of manual labour and baking in a mould. The Superstrata was designed from the ground up as an additively manufactured composite bike. Software algorithms determine the optimum position or fibre arrangement to achieve the desired parameters of the parts. This means that we have developed new strategies for designing and manufacturing composite structures that are compatible with additive manufacturing techniques, not all of which are published in our YouTube videos. We validate the design of the Superstrata with a series of test elements and prototypes using internal and industry standard test methods.
Torsional stiffness is particularly critical due to the frame design without a seat tube. The missing seat tube leads to extreme loads. To achieve acceptable stiffness, the frame would have to be significantly heavier. What do you think about this and have the first prototypes already been subjected to a DIN or DIN Plus test?
This claim is based on false assumptions about our manufacturing process. The Superstrata frame is designed to withstand the required load cases including torsional strength. It is true that the lack of a seat tube leads to more extreme loads on the frame. However, this was a deliberate design decision that results in a small increase in weight compared to a bike with a seat tube. We have already developed bikes that have passed the ISO 4210-6 test in the past and are currently working on such tests for the Superstrata.
Are there any more detailed insights into the special 3D printing process? Because in our eyes it is not possible to produce a rigid frame with melted short fibres.
What Arevo does is fundamentally different from the other composite additive manufacturing companies. That's why we've received significant investment from several Silicon Valley venture capitalists to bring our core technology to market. Where others use chopped carbon fibres and material extrusion, we use a different process - direct energy deposition - to create a positive bond between layers of continuous carbon fibres.
Essentially, it's not just about the materials, but also about how you design and manufacture the frame. We designed the Superstrata to fulfil the desired stiffness based on the measured material properties. A bike can be "too soft" with any material, not just thermoplastic. By using additive manufacturing and software-driven design, we can take advantage of the processability of thermoplastic composites while compensating for the weaknesses through the precise position of each fibre bundle.
In the promotional videos, the Superstrata has a seat tube in some sequences. However, the final frame design is supposed to do without one. Is that even possible?
In the promotional video we have shown one of our earlier prototypes to demonstrate that the Superstrata does not exist on a computer. It is the result of many design and construction stages that the team has undertaken over the last few years. In Update No. 11 you can see the full story of the bike.
You don't have anything close to a final prototype at the moment, but would like to deliver the final bikes at the end of December. Is that realistic?
We currently have several working prototypes and our development team will finalise the testing phase before going into full production. The wonderful thing about Superstrata is that we can test our bike design as many times as we like, as we don't use moulds like traditional carbon bike manufacturing. Our software and robotics allow us to not only change the composition of the materials, but also to test different designs and geometries each time. As it is an iterative feedback process, the next print is better than the previous one.
The price of the Superstrata is very favourable compared to high-quality carbon bikes on the market. How is that possible?
Firstly, we do not buy frames for resale, but manufacture them using highly automated 3D printing technology. This is not only more precise than manual work, but also saves on labour costs. Secondly, our technology enables lower development costs. We can perform multiple design iterations without the use of expensive moulds. Thirdly, we sell directly to the consumer, i.e. direct sales. Finally, we can manufacture on demand. With these advantages, we can save a lot of costs, which we pass on to our customers.
How many of these 3D carbon printers do you currently have and how many will there be for series production of the Superstrata?
We now have eight machines. We have ordered, are currently building, testing or validating 120 more. Our plan is to deploy them in the course of 2021.
As a backer of your Indiegogo project, is it possible to get your money back?
Yes, from now until the time we go into production in October, you can have your money refunded. Indiegogo has set aside a certain amount of money for this purpose. If you change your mind later, this is also not a problem. You can still order bikes after the campaign, but at the regular retail price. Orders will be accepted for production after they have been dispatched to the campaign customers.
Conclusion:
Although Superstrata has responded to the allegations and vehemently refutes them, there are still unanswered questions. The answers don't really go into detail, instead there are such universal phrases as "no matter what frame material, a bike can always be too soft" or "a bike has already passed an ISO test in the past". At least Superstrata gives supporters the opportunity to get back the money they invested in the campaign as long as production of the ordered bikes has not yet started. We were also shown a video of employees riding the latest prototype bike around a car park. Mostly standing up, without pedalling hard or really putting the bike into a bend. This leaves us in doubt as to whether the announced bike will really be ready for the market at the end of the year with its many equipment variants and seat tube-less frame design. We are curious and will stay tuned!
