Velomobile steering coupler (Quest / Mango / Others)

thingiverse

Many velomobiles use a plastic coupling part to form a universal joint. Over time, this part wears and that introduces play into the steering. Initially, the play can be eliminated by merely tightening the bolts which hold the steering coupling in place, but as more wear develops this will no longer work. This part replaces the original steering coupler in a Sinner Mango or Velomobiel Quest or Strada (and quite possibly other models too), removing the slop from the steering which results from using a worn steering coupler. In the first photo, the original very worn part is on the right, the newly 3D printed equivalent on the left. Note: This is currently experimental. I have 3D printed a part like this for use on my own velomobile and am currently testing it. Because the part is in compression due to the two bolts which run through it, I think it will be strong enough even though a chunk of 3D printed plastic is not as strong as the original milled and drilled solid plastic version of the part. At 300 km, there is no apparent wear on my steering block. It is still performing well. Another warning: It is not known yet whether it is safe to use a 3D printed part in this position. It may fail. If you print your own and yours fails, then you have done this at your own risk. I cannot be held responsible. For me this is an experiment. Update after 10000 km: The part finally broke after about 10000 km of riding. This happened quite suddenly (see the two new photos). I went from normal steering to having no steering at all in an instant. Luckily it happened in a place where I could simply brake and stop, and I then fitted the replacement I've been carrying with me for the last 10000 km and carried on with my journey. I'm actually quite surprised that the part lasted this long. It seems that PLA is a bit harder than the usual material used because there are no wear marks to speak of and no play had developed in the steering as happens with a worn coupler, but this failure mode is bad. I had hoped to have some slow indication of failure before seeing something like this happen. As such I don't recommend actually using this design for a 3D printed part. It you do so then it's at your own risk. Find other parts for velomobiles and recumbents in our webshop: http://www.dutchbikebits.com/recumbent-velomobile-parts Print Settings Printer Brand: RepRap Printer: MendelMax 1.5 Rafts: No Supports: No Resolution: 0.3 Infill: 75% Notes: I used 75% infill because this part needs to be strong in compression and it is replacing a part originally constructed out of solid plastic. My steering block is printed in transparent PLA. Post-Printing I suggest sanding the surfaces absolutely flat and smooth before use. Also rework the holes with a 6 mm drill or round file to ensure they can easily accommodate an M6 bolt.