I've been riding it around a bit. I would have responded sooner, but I have moved and temporarily had no internet access for roughly 3 weeks.
Anyhow, in comparison to the Thunderbolt:
1) The KMX is much easier to pedal. It rolls without anything rubbing, its parasitic losses minimized. With 30+ lbs of weight reduction over the Thunderbolt, I can spin the rear tire in the 32T granny gear just using my legs(It helps that the rear tire doesn't have much in the way of traction). I am much faster on it than the Thunderbolt, but I have not yet done a top speed run. I think 30+ mph is very doable right now with it(although will require a high cadence, see the below paragraph).
2) After cleaning my previous chain with alcohol, it ended up rusting to a state of uselessness. I used the 1-spd chain that came with my frame kit. It will work with my rear derailleur/cogset, but not my front ones. I'm using the middle 38T front cog and due to a clearance issue with one of the rear frame bolts going to one of the seat mount posts, I have locked out the 7th gear on the rear cog(It now functions as a 32T-16T 6 spd). It still is easier to pedal up steep hills than the Thunderbolt was, and cruising all day long at a steady 15 mph at 82 cadence is no problem. That being said, my gearing will limit me to 25 mph or so top end at 135 cadence. Next year sometime, I may be getting a Rohloff hub, if I choose a middrive.
3) The KMX frame has a 5.5” ground clearance at its lowest point and the chain's lowermost point is just in front of the rear derailleur at 5” above the ground. While riding the Thunderbolt, I feared any speedbumps or road imperfections scraping the bottom of the trike with its frame's 2.25” ground clearance and with the chain almost touching the ground at any given time. The rear suspension in the Thunderbolt kept me comfortable even over potholes, but the KMX has a wonderful seat mesh that absorbs vibrations well, even better than the seat I built out of vinyl webbing for the Thunderbolt. The KMX feels unsafe over potholes compared to the Thunderbolt, as if I am going to fall off. In the Thunderbolt, I could recline back and the top of my head would be 31” from the ground. With the KMX, I adjusted my seat as low as possible without the rear mudgaurd rubbing the rear tire while adjusting my boom for optimal pedal stroke length, and the top of my head is 39” from the ground. I am going to need to be careful in my placement of EV components to get the center of gravity right.
4) I need to order and install a front suspension kit. This thing has a noticeably higher center of gravity than my Thunderbolt, mainly due to the elevated ground clearance and rider position. The elevated ground clearance of the KMX was much needed for safely traveling at speed, but its cornering is unsafe compared to the Thunderbolt, and the small KMX seat makes me feel like I'm going to fall off in a sharp turn, whereas the oversized seat on the Thunderbolt held me in very well. I don't think anything over about 0.4-0.5G lateral acceleration is a good idea in the KMX until I get a front suspension. The Thunderbolt was a lot more stable in the corners.
5) I hate the direct steering with a passion. I will need some kind of damper. The steering feels very unsafe over 20 mph, and the slightest twitch will send me into another lane. Hard pedal strokes induce an unavoidable steering change. The front suspension might help correct these issues to an extent, but I still think some sort of damper will be necessary for my application, especially if I will be cruising at 30 mph in traffic over crappy roads or accelerating hard at a stop light. The Thunderbolt felt plenty stable at 25 mph even over bumpy roads, by comparison.
6) The Thunderbolt looked a lot better, aesthetically. This won't matter once a body is on it, but I do appreciate the KMX for its functionality.
7) The KMX frame is much sturdier than the Thunderbolt and I highly doubt this frame will ever fail.
8) The Thunderbolt was much more fun to ride while intoxicated. It felt stable and solid. The KMX feels twitchy and dangerous, and will be kept to sober riding only until its issues are resolved.
Overall, I am satisfied with my purchase of the KMX and this build will continue as parts are ordered and arrive.
ABS plastic sheeting is on the way. I won't bother doing much with it until the front suspension is installed though.
The ordering of the Rohloff 500/14 Speedhub can wait, as it will be almost useless until I have a body on it anyhow, and I don't think it will work if I decide to use a hubmotor, and I'm going to want a front cogset with a 150mm crank to go with it all to make my pedal strokes more efficient. If I go with a single-speed in the front for reliability, I would want to gear the Rohloff hub's teeth and/or front cog to allow ~4 mph at 60 cadence up a steep hill in the lowest gear, and at the highest gear roughly 30 mph at 90 cadence cruising on the flat with a top end of about 45 mph approaching 140 cadence. I think this would be a good, balanced approach with the intent of making this build a practical form of transportation, with a bit of ass-hauling capability on the side. The less failure points, the better, and not needing a front cogset and front derailleur would be nice.
That being said, I'm still considering a variety of different drive configurations.
-A Monster Clyclone XL would be delicious overkill, and I think it offers a 44T ring when engaged, and both a 44T and 32T one when not. Getting this to work with a Rolhoff 500/13 could give me a range of 3 mph at 60 cadence up to 50 mph at 140 cadence. It would be able to go up the steepest inclines, whether the battery has charge or not, thanks to the gearing range available for pedal-only input. I do not think there exists a bicycle chain that could handle both my torque plus the power/torque coming from the internal gearing of the Monster Clyclone motor if I try to get as much out of the motor as possible, so I might have to restrict the motor after the power/torque is transformed by the gearing to producing maybe 100 lb-ft up to 140 cadence, which yields about 2 kW mechanical power from the motor, plus my pedal input. I'd be heavily under-using this motor and I would like to think it would provide tens of thousands of miles like this. I think I would be hard-pressed to get any bicycle chain to last that long.
-A smaller 3000W Cyclone would be more appropriate for a middrive that doesn't kill my chain over and over again. I'm still not sure if the most durable KMC ebike-specific chains could handle this, but if they can, this amount of power would be a good compromise.
-Going to the opposite extreme, figuring out how to fit a Lynch/Agni/Etek motor to work in this as a pedalec would be a very interesting, and ballzy, exercise/ It's not only a highly efficient motor, but it would provide a dangerous amount of ass-hauling capability, and set up as a hubmotor, bypasses the chain issue. I would be forced to use front/rear cogsets/derailleurs to get the gearing range I need though. It is very heavy too, and it would be nice if lighter versions of this motor were available, say, in the region of 7-10 lbs. I tried 4 lbs of ballast on the Thunderbolt's rear wheel as an experiment, and rotational inertia heavily penalizes acceleration/uphills when operating the vehicle on pedal-only, so a heavy lynch motor would make that quite a problem during circumstances where the vehicle has to be operated with no assist. If I set it up as a middrive, I would probably need a separate chain and sprocket that isolates the pedal crank output from the motor output, and adds them together with a sort of clutch or split-broach spine.
I still haven't decided on a motor/controller/battery just yet as this new build is radically different from my old Thunderbolt. Its low weight/high strength opens up a lot more design possibilities than the Thunderbolt had. A bottom bracket torque sensor will be needed, and those aren't cheap.
I want to build up some moped rims and get a set of Schwalbe energizer DOT-rated 60 mph capable tires on them. The idea of never having a rim fail when hitting a pothole or debris at speed plus almost never any tire failures, while maintaining the requisite low-rolling-resistance to function well as a bicycle when the motor is unable to be used, all appeals to me.
Pictures of my KMX are below.