Low Racer tilting trike

During last year I have been able to ride more than 6000km with both my solar trikes (2018 STT and 2019 STT2) .

These are the 4 areas where I could gain a lot of significative experience: 

Tilting Mechanism:

after roughly 700kms with my STT2 it started to become noisy while the rotating pivot was pushed few millimeters toward the bottom part. This happened while I was riding on the SunTrip rally and therefore I have not been able to repair it effectively…

The only objective was to finish the SunTrip solar adventure even with a defective tilting unit.

Later I had to understand what caused this issue.

Confort:

I have ridden often through pretty bad quality roads and not having any rear dumping system was physically quite hard for my back 🙁

Stability:

I still felt that the center of gravity was a little too high, especially having installed 2 solar panels for 300watts (roughly 10kg including also the aluminium structure).

Motor overheating:

with Falco Direct Drive hub motor, installed on a 26″ front wheel (2018 STT) very often after few hundreds meters of altitude gain the controller cut down the power to around 280watts. This also happened quite often also with the eZee geared motor on a 28″ front wheel (2019 STT2).

After I came back I started to completely disassembly the Tilting unit.

This allowed me to appreciate all the damage that was caused by the issue decribed above.

I repaired the defective Tilting unit in such a way that the trike felt again very good when leaning into tight turns.

But this was not enough since this ‘rotating pivot’ could have caused again similar issues.

So I started to design a radically different Tilting unit.

I replaced the ‘rotating pivot’ by 2 connecting rods pulled by both Tilting arms.

On the right a short video to demonstrate how the new V2 Tilting mechanism is working

Here we can see the difference between the STT2 and the new Raptobike Low Racer I bought.

I decided that the new version for 2020 should be based on a Low Racer to improve handling, stability and also ‘ease of use‘.

STT2 versus Low racer

Here is the new V2 Tilting mechanism installed on the Low Racer frame.

We can see how the mechanism is neatly attached to the rear part of the frame. 

Since the arms are VERY close the new tie rods I had to cut few millimeters from the aluminium structure to let them move without any interference.

Here we also see that the arms are 5cm longer than previous version to increase the maximum tilting  angle to roughly 38° (from 28°).

Another area of improvement was the possibility to easily check that rear wheels are parallel. 

For this reason I have installed 2 tensioners, each one working on the axle on rear arms. 

In this picture we can see that by positioning a metal bar (38cm long) I can verify if both wheels are parallel. 

If not, using the tensioners I can modify each wheel separately. 

After few weeks I was able to start performing some tests and I could see that:

the Tilting mechanism V2

is very smooth, precise and the maximum leaning angle is reachable very easily.

the handling and the stability

are now excellent: it’s easy to go straight without both hands and at the same time the trike is very easy to turn.

– the confort 

is greatly improved with the new elastomer based suspension. After having tried tried different compounds (without solar panels, battery and hub motor) the best is the SOFT elastomer.

Here below we can see 2 videos:

– the first one to show the handling and stability of the Low racer with the new upgraded V2 Tilting Mechanism

– the second one to show the new ”elastomer” based suspension mechanism.

 

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