Startup Avial Bikes presents two working prototypes of electric bicycles, built on the basis of a proprietary patented frame of its own design, one of which is equipped with a mid-drive system, and the second with the rear-wheel motor with 250 or 350W. Each of the prototypes with a mileage of more than 1000km successfully passed all possible load and road tests – from driving along city streets and country back roads, to overcoming rocky sections in the mountain, driving along sandy beaches and mud road. Such a wide range of tests is explained by the fact that many e-bike owners use them in the city on workdays, and on weekends they can go for a drive both to the mountains and along forest paths.
Avial Bikes Team set itself the task of creating a not expensive electric bike based on a light and durable frame, which would make it possible, without significant design changes, to choose either mid-drive system or rear-wheel motor offered by different manufacturers, with power 250-350W and with a maximum torque up to 100Nm. In addition, the frame design must withstand loads of up to 140 kg, moreover, in any operating conditions. That is, in addition to city driving, which may be accompanied by crossing curbs, the owner of this bicycle should have the opportunity to ride over rough terrain, including mountainous ones, with long ascents or descents.
The design team of Avial Bikes decided to stop on square profiles made of thin-walled aviation aluminum alloys, which are much stronger than traditional 6061 and 7005 alloys used for the production of bicycle frames, to make a light and durable frame for our e-bikes. However, it is difficult to weld rolled products from aircraft alloys even in factory conditions, and for small-scale welding production, this becomes a difficult task at all. Therefore, they decided to use square profiles and special power plates that are connected to the frame of the structure we need with rivets. Such a solution, in addition to the simplicity of production, has another great advantage – in the frame design, we can quickly make all the necessary changes and make it immediately after CAD simulation.
At the same time, unlike welded frames, which have a motor bracket for fixing only a strictly defined model of the middle drive, the company’s patented frame has an original assembly that makes it possible to install either any model of the middle drive or pedals for the option of using rear-wheel drive, saying that on the basis of such a frame you can also assemble an ordinary classic bike without an electric drive.
Another important task facing our team was the comfort and ease of use of the bike. The owner of the bike should be able to move with complete comfort, which is especially important when operating in an urban environment. To do this, it was decided to install a front fork with a travel of 100 mm on the frame, and for the transmission of an electric bike with a mid-drive system, use the Gearsensor, which provides smooth gear shifting.
The frame used in prototypes weights about 3.5 kg and assembled electric bike weights within 22-23kg along with drives and batteries. This is the standard weight for most models in this price range. However, since the production of these bicycles is planned in Europe, they are conducting experiments to create their own battery with a capacity of 10.5-14Ah, based on 3500mAh cells, which will be lighter and more compact than a standard battery from Southeast Asia by 20-25%. Avial also plans to finalize all the components of the frame and get pre-production models in the style of the legendary Defender SUV of the latest generation.
Tuvie received “Avial Electric Bike” project from our ‘Submit A Design‘ feature, where we welcome our readers to submit their design/concept for publication.
I suspect having a working knowledge on How To Weld would have helped immensely…