So with the previous reverse engineering video I felt like it was very technical in some ways and not indepth enough for other aspects. However, with Sterzo currently being sold out, and it’s long list of problems, I figured a cheap 3d printable version that fixes at least some of those problems were in order. So the github at https://github.com/kwakeham/zwift-steerer/ has been updated with Step and STL files. Suggestion is to print them with min of 3 – 4 perimeters and solid top and bottom layers. Sterzo is about 1mm thick plastic, so standard 0.2mm layer height = 5 walls and 5 top/bottom layers, but if you up the infil to 40% it’s generally fine You want extra walls because the socket head cap screws for the bearings are threading directly into plastic. It’s not a problem since there is zero pullout load.
And mentioning pullout load, unlike how I think Sterzo is constructed, there is ZERO lateral load on the bearings. This is because there are 5 and not three, so the swivel bearing in this design takes no lateral load, only radial. You’ll also note the whole thing is on about a 73 degree angle and yes, you’ll probably want to raise your trainer to compensate for the extra 45-50mm of height. The reason is that this is the head tube angle most 54cm bikes have. So the steering swivel point is inline and colinear.
However, one thing I didn’t think through is that because the point where the weight of the wheel is now resides on an inclined circle, that when you steer it wants to lift the bike up a little. So Elite’s Sterzo tries to pull your bike fore/aft a cm and I lift a few mm. Neither is ideal.
The code runs on a nrf52DK, but any module should be fine of the nrf52832 variety. I have no desire for the 840 because the USB implementation is still “wobbly”. The nrf53 seems to make little sense to me. The nrf52810 is just a cheapie 832. If you no idea what I’m talking about then this aspect might not be for you.
The potentiometer isn’t the greatest solution. I know this. I have the magnet sensor on a breakout board. So if you’re interested in upgrading your dumb Sterzo to a smart one I might be convinced to design a board that could be used on an updated STERIO and the original Dumb Sterzo. Email me at keith@titanlab.co