i see what you’re saying but if that’s the comparison then just use chains or gear drive
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You still need gears or belts for the wheels – plus more if you want to split the power. You’re not replacing anything, only adding more
For no benefit
lets count moving parts:
Belt Drive: 2 motor 2 wheel drive– (2) motor pulleys, (2) belts, (4) idler pulleys, (2) wheel pulleys (10) total moving parts - half the traction
Differential Drive: 2 motor 4 wheel drive– (2) motor shaft/cogs, (2) crown wheels, (4) output cogs/shafts, (4) “small” gears (12) total moving parts - 2 extra moving parts, 2 extra driven wheels & twice the traction
You forgot the two wheel anchors for the differential, so that’s two more unless the axle spinning inside the wheel is okay 
Plus you should not compare belt to gear, compare gear to gear which means the non-differential method has only 4 moving parts: 2 motor gears, 2 wheel gears - 4 moving parts total.
If you want to compare belt, then use a belt differential also.
So gear drive is 4 moving parts and gear differential is 14 moving parts.
So you’ve got 2 to 10 more moving parts now for no benefit. I never reach the point of my polyurethane wheels skidding because they don’t have enough traction.
You’re searching for a problem with a solution in your hand.
@b264 what about a mountain board, high gear reduction (high torque), steep incline on loose dirt… the traction of 4 driven wheels could conceivably offer superior ride quality compared to 2 driven wheels… no?
No because in that case you’d just use 4 motors, even if they were smaller
but what’s better in the scenario if you’re limited to 2 motors… 4 wheel traction or 2 wheel traction?
Both are 2 wheel traction. If one of the wheels slips, the other loses power
If you REALLY want to find a use for this “solution” then find a way to make a shittier esk8 using a differential – THAT’S CHEAPER than a regular one. If you can make it dirt-cheap (and maybe shittier) then it will be a real solution
The differential system would have to be cheaper than another motor and drive circuitry – but it’d have to offer some benefit over a 1 wheel drive system (which I fail to see that part as I ride a 1-wheel drive all the time)
Honestly an open differential seems to give you little to no benefits.
You’re likely much better trying to simulate a LSD.
In a dual motor drive you could theoretically have a friction pad between the two cans’ ends. Won’t generate any heat during normal operation as wheel speed differential is minimal unless one has lost traction. If one slips you get a little extra power through to the other side. This in conjunction with traction control integrated in the two vescs would limit how much the unloaded motor could slip against the one still with traction(sets a maximum speed difference between motors), effectively limiting how much wear / heat could be generated on the pads.
This really shouldn’t be all that hard to implement, considering a lot of motors already have threaded holes on the backside. Definitely would be motor and mount specific though.
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but would that be a deficit for the differential? doesn’t the slipping wheel on the differential have as much torque and power as a slipping wheel with belt drive? wouldn’t the other driven wheels on the dual motor differential be on the truck on the opposite side of the board presumably be farther away from the loose trail material than would be the case with a second motor on a dual belt?
Yes
Yes
Yes
No, both back wheels would be on the opposite side from one another, regardless if a differential was used. For example, one wheel on the left side and another wheel on the right side
With dual motors the wheel with more traction would be powered by its own motor On a differential, the power would be robbed by the slipping wheel
my point is with 2 motors regardless of dual motor & differential (4WD) vs. dual motor & belt (2WD)–
in both cases with one slipping wheel there is still one or more other driven wheels on the board via the second motor.
so if both options lead to a second motor-driven wheel, I don’t see it as a deficit acting against the dual motor dual differential option.
Unless you’re referring to belt-driven differentials, I’m referring to gear drive only as it’s the closest analog. so “dual motor & gear”
In either case 2 motors will give you at most 2 powered wheels. So having the extra complexity of the differential system is just added weight and failure rate for no more benefit
i think in the scenario with one slipping wheel, with the 4WD system i have 2 driven wheels and with 2WD i’m down to just 1 driven wheel…
First of all, your use of “4WD” and “2WD” is misleading at best because a single differential and motor would be given the moniker “2WD” whereas two motors driving one wheel each is something totally different and definitely not the “2WD” thing
As for the rest of it, I will offer physics consulting services if you send me a purchase order. You’ve exhausted your free trial.
the board i’m discussing has one differential on the front and one differential on the rear (2 total differentials), each with one motor attached (4WD). the belt drive has 2 motors and 2 driven wheels (2WD).
That is 100% not what the “2WD” moniker means. Please research first. I’m done here. You will believe what you want to believe, regardless of facts.
Guys I dont really want to interrupt your discussion here, but who would make differential for longboard? 
There are so many more needed parts than some kind of diff… 
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Thank goodness, someone with facts has arrived