LEVA-EU member Podbike has toured the uniquely designed FRIKAR e-bike around various European trade shows, delighting audiences and making fresh engineering discoveries along the way
‘Podbike, meet din 79010’ – Germany’s strict safety standards
Germany’s rules for bike design and safety are the gold standard across Europe. The Podbike FRIKAR is so unique, that it’s not completely clear which category of bike design it belongs in. Podbike has chosen to abide by Germany’s rules for cargo bikes, as the LEV can carry two people: one big, one small, or one rider and cargo in the rear.
For example, the FRIKAR should be able to roll off a curb onto the road without any fear of damaging the bike. These simple drops from curb to road surface occur all the time on a bike, so it was necessary to test the effects of constant bumping such as this over time.
To simulate long-term riding, Podbike has developed a power-driven test rig that allows a FRIKAR to ‘drive’ for days and days on rollers without a break. The fatigue data gathered provided interesting insights, which will assist in ensuring Podbike is first-in-class when it comes to velomobile stability and durability.
What to do when shock absorbers are not absorbing sufficient shock?
The biggest finding was that the front suspension wasn’t behaving as expected, being too stiff for the test rig. The suspension wasn’t absorbing enough kinetic energy, making for a bumpy ride and some complex handling. Additionally, unnecessary pressure was exerted on the bike’s chassis which would cause damage over time.
As a result, Podbike has chosen to change the springs on the FRIKAR’s front shock absorbers. In laymen’s terms, the team has made the front suspension softer. This more supple suspension creates more give in the front end of the FRIKAR, reducing stress on the chassis, and taking a load off the front of the chassis and all the bike’s other components.
The new springs have different diameters and steel thicknesses than the old ones. They will add a little extra weight, but not much – just a few grams.
Why redesign the front suspension now?
Readers may ask, why did Podbike wait until this late stage in the design process to make this change?
The short answer is that there was not enough test data until now, despite the FRIKAR undergoing 2 years of test driving with the old suspension springs on roads in Norway.
After some stress cracks appeared in the chassis, it was realized that reinforcement was required. Following this, it was assumed the issue would be solved, but the amped-up fatigue testing this summer on the roller rig revealed that more refinement was needed. Hence, additional suspension development!
Development enhances the FRIKAR to the max.
The good news is that following the installation of softer front shocks it was discovered that they extended the FRIKAR’s projected longevity by three to four years!
A great result, but Podbike is committed to further development as to meet the German cargo bike standard. Unfortunately, these changes to the front suspension mean the bike’s production will be delayed a little longer. However, while disappointing for some, Podbike’s dedication to quality is highlighted, ensuring only the most superior of products reach end-users.