Originally Posted by
FBinNY
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As you suspect, they often require a special hub and axle which is more like a pedal spindle than typical hub. However, some have standard shells and axles that are simply moved across for single side mount..
Not quite. Many recumbent trikes used “through-axle” mountain bike hubs with 15mm or 20mm diameter axles when they first appeared. Now they are specifically manufactured for trike wheels with disk brake mounts or drum brakes.
There are a few recumbent bike part suppliers out there but they tend to offer complete wheels instead of bare hubs. Look at Hostel Shoppe or Utah Trikes.
FWIW: I was manufacturing recumbent trikes 40 years ago. I have tales to tell about hubs.