For almost a year now, I've had a GEBE system on this upright bike:
No problems whatsoever; it's been great. I got curious over the weekend, and swapped the rear tire from this bike, and the GEBE system, onto my Catrike Expedition (no photos at the moment, sorry). The only difficulty was making a mount/connection point for the engine support strap to secure to the frame, but that didn't take too much time and headache. FYI, unlike a two-wheel recumbent, I didn't need a longer throttle cable, because the cable snaked down the side of the seat frame and looped up at the handlebar just the same as the shifter cable does.
My question is more bike oriented than GEBE/motor oriented. I swapped in the upright bike wheel because: the wheel and tire (and to my untrained eye, perhaps the spokes) from the upright are fatter/beefier than the Catrike wheel and tire (the swapped-in wheel/tire width is 1.60, maybe 1.75 if IIRC); even though the upright bike gearset is seven speed to the Catrike's nine, the one or two gears I use most with a motor seem to translate without adjusting the derailleur cable; the Catrike has a quick release wheel, so no go on the GEBE; and, I already had the GEBE drivering installed on the upright wheel.
All seems to fit well, wheel rolls true, lots more clearance on the Catrike for wheel and drivering than the fraction of an inch it had on the upright. Just as on the upright, it seemed to work fine. No problems on a 10 or more mile ride. So, my noob question on the wheel: am I risking any sort of catastrophic failure or other big problem just by swapping wheel to wheel? To explain a bit more, is there some important aspect, measurement, or other engineering-type issue I don't know about when swapping wheels that could/will lead to a problem, or is the answer simple - any problem will be immediately apparent, and if it fits and works, it should work long term? As I mentioned, the swap went smoothly and the motorized Catrike seemed to run like a top.
FYI, the GEBE on the Catrike also runs 7-10 mph faster, by a rough estimation. The upright topped out at 22 mph by my GPS on the flat (I got the GEBE drive gear that's for less high end, more torque - can't remember if that's more or less teeth), which was fine with me. My 14-year-old son (a beef who's bigger than me) begged to ride it, and I paced him on my motorcycle; with my speedo registering 32 mph, he was slowly pulling away (my speedo may be 2-3 mph "generous"). Whatever the exact speed, it's definitely faster on the Catrike with that reduced frontal area hitting the wind.
A silly question perhaps, that demonstrates my meager knowledge of the mechanics of, and working on, a bicycle, but any input would be most appreciated. If I'm asking for major trouble by swapping the wheel from upright to Catrike rather than searching out a truly compatible wheel if that's necessary, I'd like to find out from you rather than from splattering myself during a ride. Many thanks.

No problems whatsoever; it's been great. I got curious over the weekend, and swapped the rear tire from this bike, and the GEBE system, onto my Catrike Expedition (no photos at the moment, sorry). The only difficulty was making a mount/connection point for the engine support strap to secure to the frame, but that didn't take too much time and headache. FYI, unlike a two-wheel recumbent, I didn't need a longer throttle cable, because the cable snaked down the side of the seat frame and looped up at the handlebar just the same as the shifter cable does.
My question is more bike oriented than GEBE/motor oriented. I swapped in the upright bike wheel because: the wheel and tire (and to my untrained eye, perhaps the spokes) from the upright are fatter/beefier than the Catrike wheel and tire (the swapped-in wheel/tire width is 1.60, maybe 1.75 if IIRC); even though the upright bike gearset is seven speed to the Catrike's nine, the one or two gears I use most with a motor seem to translate without adjusting the derailleur cable; the Catrike has a quick release wheel, so no go on the GEBE; and, I already had the GEBE drivering installed on the upright wheel.
All seems to fit well, wheel rolls true, lots more clearance on the Catrike for wheel and drivering than the fraction of an inch it had on the upright. Just as on the upright, it seemed to work fine. No problems on a 10 or more mile ride. So, my noob question on the wheel: am I risking any sort of catastrophic failure or other big problem just by swapping wheel to wheel? To explain a bit more, is there some important aspect, measurement, or other engineering-type issue I don't know about when swapping wheels that could/will lead to a problem, or is the answer simple - any problem will be immediately apparent, and if it fits and works, it should work long term? As I mentioned, the swap went smoothly and the motorized Catrike seemed to run like a top.
FYI, the GEBE on the Catrike also runs 7-10 mph faster, by a rough estimation. The upright topped out at 22 mph by my GPS on the flat (I got the GEBE drive gear that's for less high end, more torque - can't remember if that's more or less teeth), which was fine with me. My 14-year-old son (a beef who's bigger than me) begged to ride it, and I paced him on my motorcycle; with my speedo registering 32 mph, he was slowly pulling away (my speedo may be 2-3 mph "generous"). Whatever the exact speed, it's definitely faster on the Catrike with that reduced frontal area hitting the wind.
A silly question perhaps, that demonstrates my meager knowledge of the mechanics of, and working on, a bicycle, but any input would be most appreciated. If I'm asking for major trouble by swapping the wheel from upright to Catrike rather than searching out a truly compatible wheel if that's necessary, I'd like to find out from you rather than from splattering myself during a ride. Many thanks.