I’ve been fantasizing about a drive system that would allow the use narrow hangers, small wheels, and small motors high off the ground. to meet these requirements, i feel that outward motor mounting is needed. for that to work, i have considered a system involving two idler gears on the same shaft
i would love to hear your thoughts and criticisms of this approach. i don’t know how to cad or draw beyond using microsoft paint, so the following sketch is not drawn to scale. i have not determined the specific gear sizes needed to provide adequate reduction, and have not determined how they will look when drawn to scale (and the resulting motor mount plate dimensions)
if such an arrangement turns out to be feasible, i would like to assemble a prototype drive built from 100mm surf rodz tkp’s, 76mm x 57mm ahmyo akasha’s, 5095 motors, and off-the-shelf mod 1 or mod 1.5 gears. the prototype motor clamp would be cut from soft aluminum. if the prototype works well enough, i can have the plate machined with bearing seats on both sides of the idler gear shaft
please know that i’m not ripping off @moon’s 4gd design - in fact if anyone else intended to commercialize a project like this i would rather buy it from them. i have reviewed my moon nda’s and the pre-release designs he has shown me, and i can assure you all that there are no similarities. if anything, it is kinda similar to his 3gd but moon is happy with wider hangers and inboard motors
It’s not a rip off. His product never came to market, and this has a completely different motor location.
I’d use 5055 motors if they’re gonna be on the wheel side of the motor plate. Moons 4 gear designed was standard orientation with upper and lower idlers.
I’m sorry but we’re far beyond reinventing the wheel here. There’s not much new under the sun happening with drivetrains right now
i can save width (looking from the top down) by having idler gears on separate sides of the motor mount plate. I also won’t have to worry about the torque on the shaft from the gear being further away from the motor plate, which acts as the fulcrum. In fact, any torque from the pinion and idler #1 might be offset by the torque from the idler #2 and spur
Probably not, what you’re showing is 2 motor pinions driving one wheel. The OP suggested one motor pinion driving one wheel, but with some intermediate gears.
On top of having the motor on the other side of the wheel, hence allowing for narrower trucks, there is the advantage in this setup of allowing higher gearing ratios, when you cannot go any smaller on the pinion (need enough teeth to engage), or any bigger on the wheel side. (needs to be smaller than wheel diameter + clearance).
However there’s no free lunch, with the extra weight, extra moving parts, and extra friction…
Note that this is presented here with gears, but that could equally work with belts and chains, which would allow arbitrary lengths between the axles/shafts and more freedom in the sizes of the sprockets/pulleys, because on the presented pic, there are actually some heavy constraints on the width of motor, and size of idler gear #2, and with size of gear#1 and size of hanger clamp.
