Open differential Electric Skateboard - Single motor dual rear

u just add thick diff oil. most of cars do that

my concern is the heights. it could use dogbone and use higher kv inrunner to torque conversion, to reduce the h. But for that kind of ,u can only use for penu wheels. not very realistic.

it would be more realistic to adapt some of leanboard design with dogbone adaptation.

Newbie here. Is this idea dead? Couldn’t find much reference anywhere else, this thread seems to be the only one with serious conversation. And it’s almost a year since the last post lol. Everyone seems to be moving towards hub motors at this point; is it that much more superior over a single motor with differentials? Am thinking primarily of the cost and weight savings, and with the differential, we can now place the motor in a different place (center of the board under the deck? Or on top of the deck, connected with belts through the deck?). Are there no parts available because no interest, or nobody likes the idea and thus parts were never found/built?

Thanks in advance!

Reference links:

https://endless-sphere.com/forums/viewtopic.php?f=35&t=63495&start=50

The more complicated the design, the harder it is to apply commercially…in terms of functionality and cost

No doubt part if the case here

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just laughing at the tags #veganboard for life bro

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I can understand wanting to have a diff with just one big motor but why an open diff? These are terrible in cars and will take away from performance. Where are the Helical LSDs or Clutch LSDs just please no torsen set ups lol

Imo a dual motor set up is a hell of a lot cheaper and less complicated than a proper differential set up that could emulate a dual motor set up and in the end you still have 1 motor vs 2.

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Don’t know the more complex differentials, only know the basic one, which I suppose is the open diff. Is the power loss bad? And an open differential looks like a simple enough device to mass make, certainly easier than a motor. I dunno, just a noob thinking out loud here.

Yes, the idea is dead.

Two motors (one per wheel) is much, much, much better than 1 motor. The only reasons cars have differentials is because they can’t fit/afford to use 2 engines. The electric cars use one motor per powered wheel, just like esk8.

Essentially, you are adding complexity (increased failure rate) and weight for a worse end-result.

Also if one drive train were to fail, you’d have no brakes…

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Open diffs suck.

Torsens are actually pretty good when you consider other factors compared to clutch/helical(outside of function)

Torsen will only let loose when the limits of adhesion on both tires have been exceeded, whereas the open diff will let loose when the limit of either tire is exceeded regardless of the condition of the other tire.

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All I know is that the Torsen diff in the Miata makes it hella hard to drift, I went from on Vlsd in my car to a clutch type. They work the best but clutch types require lots of maintenance especially when you are beating it to hell.

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Wait I forgot this a esk8 forum haha

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This lol esk8. Yeah torsens are shitty to drift with. And if your at the limits of a torsen for road racing 1.5 or 2 way diffs are good upgrades… but I don’t think I’m gonna see anyone trail braking at the edge of grip on a skateboard…so 1.5 and 2 way are useless lol

Also…dual motor with traction control… It’s kinda already like a 1.5way

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Thanks for the explanation guys. Saved me a lot of time exploring an idea that’s obsolete :sweat_smile: oh well, dual motors it is.

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but is 2 wheel drive with 2 motors really better than 4 wheel drive with 2 motors…?

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Yes  

a lot of the time this forum kind of shuts down innovation. I’d like to see a dual motor 4wd before we dismiss the idea as “bad”

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Feel free to do it and let us know :smiley:

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seconded.

so what’s the supposed downside of having twice as much traction?

Traction isn’t usually in short supply unless you have enough torque to spin the wheels.

The downside is adding more parts and ways to fail for no real benefit. Cars use a differential as a workaround to a problem – a problem you don’t have on small electric vehicles. You are adding more ways to fail in order to use a fix which adds failure modes.

It’s a bit like cutting a piece of paper in half so you can use some badass tape to hold it together and comparing the quality to the uncut paper

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@b264 what’s the supposed downside of fully enclosed/protected gear reduction/differential as opposed to exposed belts which can slip/snap & with half as much traction?

and are we sure there’s more moving parts to fail? seems to me like it’s replacing one set of moving parts with a different set of moving parts while improving traction on high torque setups ie mountain boards…