KEEP IN MIND that this quad is evolving from my upright bike and recumbent tadpole camping trips through the 5 deserts of the American Basin and Range Geographic Province…
The quad could handle this ride on a day trip, the trike couldn’t.
Moving base camps entails loads over 500 pounds gross up 15% grades on rutted loose surfaces.
KISS (keep it simple) is number 1 guide, which can’t always be kept.
Negative – Suspensions are vulnerable.
Negative -Tadpole conversion only amplifies the torqe weakness of a center beam with a rear wheel fork.
So its a flexible ladder frame. A bonus is that the center is open for mid-drive components … gets the extreme low gearing.
I require fat versatile tires. The next set will be selected from Mod Trial 406’s. I would like to try larger wheels like Trials 559 (Two Sixers) or MTB 622 (Two Niners) but won’t until the next frame version, an extra $2000 shows up, and a time machine that stops my aging at its current 72.
AND a 6 Gear Inch drive-train (yes that number is six)
The Schlumpf Mountain Drive with dual 27T/53T rings paired with an ICE Capreo 9T/46Tcassette on 60-406 Big Apple wheels did produce 6GI to 120GI. The 6GI is just about right for those loaded soft hills. The 120GI is for safety keeping a bit of tension in the chain on potentially runaway down hills.
WITH A FATAL FLAW: Remember those hills … speed is 2mph going to 1mph… the chain is barely moving and has half its maximum tension … a down shift is needed for steeper incline … to shift it is ABSOLUTELY necessary to release the chain tension or skip, snap, crackle, pop without shifting…so its done … nothing driving the rig up … BUT gravity continues to drag the rig down … so quickly the rig almost stops … forward progress ceases without the shift…and you are on a steep slope hoping the braking will hold…..
Some other means of shifting NEEDED. Internal Geared Hubs do NOT have the required tolerance for these levels of input torque.
LATEST DRIVE TRAIN:
Front dual ring 29T/53T or Schlumpf Speed Drive.
Mid Nuvinci N360 16T In / 16T Out from Disk rotor holes.
Rear is a fabricated two gear sequential shifter integrated with a quasi-positraction differential.
LINK 2 Two Speed Gearbox.wmv
3 inch twist for wheels climbing obstructions (larger wheels would enable more)
6 inch absolute clearance (no hanging derailleurs).
Clear center space for drive-train.
Sliding utility mounting rail to rail eg seat, mid-drive, racks.
Shorter crank boom.
Four Wheels distributes load over 4 tires
better float over soft ground /or/ allows a heavier load.
tires wear longer better riding stability and balance
eg. side slope tilt goes to 35° from 25° of tadpole.
Two Tracks straddles mid-obstructions rumble strips humps between two-track trails and roads
Positraction Differential <loose surface, snow / ice> both wheels powered. Only 1 wheel needs traction for drive power.
Steering is maneuverable less yaw and roll ? little brake steer (Bryan Ball)
Lifting front-end enables easy moving on Rear Freewheels.
Lifting front-end so quad is on Rear Freewheels enables vertical parking <garage>
Suited to a wide range of riding contexts (How its ridden, where its ridden) Off-pavement riding is enabled Road touring is enabled
Fixing flats, changing tires is easy for all cantilevered open wheels Convenient large behind the seat storage platform (watch for Fargo’s floorboard) Center rear trailer hitch. AND takes the options / accessories of tadpoles etc.
Terrain Convertible. How easy it is to change wheels sets; roading to camping to snow or sand (now that FAT wheels have arrived). No need to change drives … this one covers all.
Why not QUAD Wider turning circle (fixed, fall 2011) Drive / Chain line more complex (fixed, spring 2012) Can’t Z-turn through narrow passages (doors, gates) (v2 will be narrower) A weight increase. More parts, especially field unrepairable and one-of-a-kind.parts. Harder to pack for shipment (fixed with couplers, fall 2012) Fenders (¿ in the desert?)(¿loose hand carting?) NO fenders are best, (fall 2012 )
Why not a Tadpole? Why not a Delta?