Yea no. I did mostly parametric cad and borrowed a cnc machine from a friends shop for a bit. It was milled from 6061 alu of course.
I have literally no idea what part of a simple esk8 differential would require a CNC to create. Unless that’s the only thing you had access to. At the same time, I have zero clue who has CNC access and no manual. TBH I don’t really call making something simple in “parametric CAD” and sending it to somebody with a CNC “Machining” but I’m a mean internet manchild.
Either way, probably not worth an argument from me. I just don’t think you came anything close to fully exploring this at the age of 12 and your conclusions should probably be looked at again/revised.
Can you go in depth on your double the points of failure remark? I see nothing except redundancies added in the grand scheme of things that mean anything.
Maybe we’re on a different page of understanding.
I’m in no way trying to equate this to a dual motor setup. If you don’t have space/weight constraints, dual motor is going to mostly be the better option.
However, for people already enjoying a single drive board, going from 1WD to 2WD can be quite useful it many situations without a ton of shit being added overall. In my needs - being afraid of losing a single belt that is the difference between me being able to break or not going downhill into traffic. Why is this a concern of mine? I’ve seen it happen and the outcome wasn’t fun or pretty looking.
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Why not use a analog deck with no motors? been talked about several times that 1WD has issues when braking and lifting a drive wheel when turning. Both of these issues are not addressed with diffs.
I’d agree there is enough power in a single motor but traction is a issue unless you travailing in fairly straight lines (looking at stereotyped Americans hear who don’t do cornering)
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I never said I “sent it to somebody with a CNC”? Once again, I made cad drawings, 3d printed to test fit, then bought aluminum stock, made gcode, and loaded it onto the CNC machine myself. How long have you been building for?
In regards to your points of failure question, in a single belt drive, you have 2 gears and related bolts that may fail, in a double belt drive you now have 4 gears and related bolts that may fail. In a differential setup, you have the 4 gears and related bolts that may fail, as well as an entire, tiny differential. I’ve built everything from single motor to quad motor boards, if braking on a single motor board for you isn’t enough, you need to either reprogram or reevaluate your longboarding skills.
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Never said breaking on a single motor board isn’t enough for me lmao.
You’re somehow seeing a point of redundancy as a point of failure and I don’t understand how.
Single motor board.
Typically one gear + belt driven wheel.
With differential’
Now two gear + belt driven wheels
One belt/gear/w.e on one side breaks
Guess what lmao, you have another side.
Why are you trying to troll
Esk8 building isn’t hard dude. Esk8 building shit that works and is reliable somewhat is. Which you stated earlier - you failed to do. I fail to understand you.
it does add redundancy, but it also complicates things way more than they need to be, thus resulting in more failure points with the only gain being traction? I’m not trolling, I’ve built boards for myself as well as boards for friends and family since 2016. It’s only hard to build reliable if you
- are bad at it
- don’t have the funds
- are designing and making a completely new drive train system from scratch
I’m not gonna argue with you anymore. I’m not saying it isn’t possible to do, I’m simply saying its more cost and space effective to just buy a second motor. Just run dual diagonal if you don’t have space.
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Traction and torque steering? Punching out of a hard corner full power, single drive is going to slip if it is on the side opposite the turn, not to mention that any loss of traction and skidding is going to try to steer the board.
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Lol. I’m not sure if you’re implying that you can slide on pneumatic wheels or really soft thane, if you can then bravo, sorry for your ankle when your board flips. If this is not what you’re implying then lol again. If you’re satisfied with the traction and power of braking a single wheel can get you, then you should re-evaluate your eboarding skills.
No. A differential built properly is a very reliable thing. It is just a set of mechanical gears, 4 sets meshing, 2 bevels. Cars run them for hundreds of thousands of miles with just an oil change. A second motor however, looking past motor issues like sensors, you have many additional fets that can fail, drv chips, wire connections, etc etc. Not to mention that 2 smaller ESC and motor is going to be less robust in some ways than 1 larger one given our current selection.
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has anyone made a live axle longboard truck? (basically like a 3 link truck) Doesn’t seem like a complicated thing to design.
Then it would be trivial to add a COTS diff.
I also wonder if rounded wheels like Foamies reduce scrubbing due to the skinny contact patch.
I have been thinking about someday trying to make a bajaboard style suspension + steering system that bolts onto standard truck holes, those use drive shafts and E-Diff not live axle.
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These are not incorrect statements, but beg the question: “whats the goal?”
Based on what you mentioned “Punching out of a hard corner full power” this sounds like a toy/sport PEV at this point not a commuter PEV.
If the goal is reliability then a single motor drive as Brian (@b264) mentioned (additionally he commutes daily [to my knowledge] with his boards which IMO puts weight in his opinion) is going to be more reliable than a single motor with differential alone because of the lack of additional parts. Regardless of the track record of an automotive grade diff.
If the goal is to illicit better performance from an otherwise space constrained board - then sure, more traction and stability but again, these come at a cost some of which tend to be ignored when performance is all that one cares about (Maintenance, Reliability, Engineering, etc).
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Why can’t it be both? Nothing wrong with having fun on the way to work?
I agree if the goal is solely for reliability, then a diff is definitely not the way to go here. But this thread also is not “how do I build the most reliable board”, because that brings in options of direct drive systems etc.
I think maintenance is going to always be right behind performance, so anyone seeking performance is going to be aware that more things needs to be taken care of.
However I don’t like how conversations like this always goes astray. Why is it that when a performance part comes up, that the conversation always goes but it’s not reliable. Like have ya’ll seen how much race cars gets rebuilt every race. No need to go to that extreme, but I wish the topic stays on the pros and cons of a differential system vs twin or quad drive system, instead of 10mph city commuters going but it might break!!!. Like great, got it. Now how do we machine a reliable diff?
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failure point discussions have to be relative, not absolute
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This should be one motor, the spiral gear to change the direction of force and then an axle go both wheels.
I thought about a single 63100 or something and dual output shafts. You’re essentially riding a fixed axle then and you’re going to have terrible turning characteristics. Anyone who’s ridding a 4 wheeler on the street knows how this feels. You lose tons of traction as your wheels begin fighting each other through turns.
I would like to throw out there is a cool spur gear differential that does not use expensive bevel gears.
vs
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I agree, but typically my Ducati is less reliable than either of my Honda or Kawasaki motorcycles. Likewise my RAM 1500 is more reliable than my Focus ST.
Performance Vs Practical not generally a 1:1 for Sport vs Commuter so I get you. The topic of the thread is “is it possible” not “why shouldn’t you” so you are 100% on point.
The point of argument that I jumped in on was not the main topic of the thread but simply “Why bother” as asked by @b264 which is a valid question in the grand scheme of things.
I agree with the sentiment here but I’m not sure if I would consider a Diff as a performance part in this scenario.
Getting a (pair of) motor(s) big enough to replace two (four) other motors is one problem, then you have additional problems such as braking and even the motor controller for a motor big enough to replace two 6374’s would need to be beefy enough to push the current. On top of that, if you wanted traction control not having independent controllers on each wheel (motor) would effectively remove this as an option.
So to the point of the thread can it be done - I’m sure it can be done, and I’d be happy to try and tackle this over the next winter if someone else doesn’t before I get my MPCNC setup. I just don’t see the performance benefits, or cost benefits. Then again all of my interest in eSk8 is in the eMTB area which may be coloring my opinion.
My idea is that a diff truck would allow a motor to be mounted via driveshaft to the board instead of the hanger. This lessens weight and would allow the board to feel more nimble.
I’m thinking very out of the box on this at least, to me, it’s not like, hey lets move the motor slightly on the truck and add a bunch of parts.
What I imagined when I see differential is: A central motor housed in the center of the board, inrunner type in the 80-120mm size capable of 20+kW, at 100k+ RPMs, using a go-cart ESC, sending power to a single dual speed transmission to distributing power to both axles via articulated twin drive shaft to each axle, using limited slip differentials. So yeah, very performance oriented.
Twin driveshaft would be counter rotating to stop any kind of torque steering at the truck, maybe even an electronic posi-lock for full diff locking for AWD
I think, if this can be done at the RC car level, no reason why it cannot be scaled up to eboard level.
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I ride single drives all the time, even in the rain and sometimes snow. Obviously they have less traction than dual, but they are relatively straightforward to operate.
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That’s 99% marketing bullet point and 1% real life problem. I ride singles all the time.
a diff is just an over complication for a skateboard where the wheels are ~ 8 inches apart.
my current build is an all wheel drive (4 hub motors) with the left and right side on separate throttles and the only time steering is difficult is if I have full throttle on the left and am trying to turn right… and the wheels are 25" apart on that.
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4 wheel ultra compact gear drive 5045 is what I wanna see. Weight of two 6374s
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