Wether you dumbed it down or not your argument is flawed…cars are not one wheel drive (or diagonal drive), they simply have an ability, due to the diff, to transfer torque variably between the drive wheels…
I think the real truth here is that a differential has the ability to drive one or both wheels… but normally it drives both as load is equal across both.
Most common vehicles have 50% or more of the available wheels as drive wheels. And mostly it is either at the front or the back or both. Rarely if ever would it be diagonal.
I will probably never use single drive or diagonal drive on my eboards…
I actually don’t like the additional weight at the front as I ride boards with kicks and I use the kick to pop-up over obstacles.
I also don’t like wires running everywhere.
and I also think that it would contribute to torque steering & braking (which I think is probably easy to counter by tilting the deck against it)
Well, as I have witness this on a few occasions I’ll throw it out there…if you have a 2 wheel drive car, Jack up the end with the drive wheels and start it up. Put it in gear and watch as only one wheel spins.
Don’t appologise & don’t feel discouraged… this is an open forum for discussion, it is about learning and sharing facts & knowledge. There will be plenty more discussions in the future where two people don’t agree. It’s our job to openly discuss and “work things out”
Let me just say, It is never a good idea to “dumb” down things for anyone, especially if that blurs the lines between fact & fiction.
It’s everyone’s job on this forum to speak their mind and share there opinions, wether they are right or wrong. Its also everyone’s job to speak up to ensure every post is accurate and true. This is how me all learn.
Not sure why everyone always assumes that the theory of an inside an outside difference in wheel speed even exists with skateboarding…Your board (on any traditional skate truck turns from the center at the kingpin. You can turn your truck as sharp or as little as you like, but both of your wheels will turn at the same exact speed. The reason a car needs a differential is because of the fact that the wheels don’t turn at a single point in the center of the axle. They turn individually on spindles, creating 2 individual turn radius’.
Also, because of this ^ it doesn’t matter how you mount your motor or motors. There isn’t going to be a pull to one side or the other. It’s not possible.
As long as the wheels are separated by an axle, and are rolling on two adjacent lines one wheel MUST spin faster than the other wheel at some point when making a turn.
However I think it is worth noting that on a skateboard this might not be noticeable or measurable, due to two things.
Most skateboard truck hangers are not very wide, so the wheels are fairly close together anyway… making the distance travelled by both wheels during a turn fairly similar.
When riding a skateboard rarely do we corner sharp enough to notice, most turning angles are very obtuse. Maybe if you where rolling around in a circle with a one meter radius you might notice some skidding.
In terms of the Diagonal Drive Discussion, this is what I believe happens.
Yeah I know… I can’t really talk cause I have never ridden that way… But i have ridden single drive and it happens, DD is basically two single drives.
I think it would be more noticeable during braking, but like I said easy to counter by tilting the other way.
But YES this is just my theory… have not done real world test…
Someone with a DD should setup a test, load up the deck with a “dead” weight drive it off down the street at full speed then slam on the brakes and see if it tracks to one side. Of course as a rider you will counter it with tilting, but a dead weight cannot.
I can prove it. Keep in mind I’m talking and thinking about a skate truck. You are talking about a vehicle. Because the skate truck turns only from the center it acts like one wheel. Picture a truck that holds one 10" wide wheel at either end of the board. When you lean both wheels turn in toward the side you’re leaving to right? The board will turn in a circle. Now ask yourself this. Does the outside of that one wheel turn faster than the inside of it? It can’t. It’s impossible.
Its not impossible it actually happens.
the truck twist does change things a bit so yeah you cant compare a car to a skateboard… let’s stop doing that.
but the inside wheel does always turn less that the outside.
I agree with @lowGuido in real world situations to a certain extent.
Just so you know: I have never ridden Dual diag, or dual rear… only single drive on a couple different builds.
I rode my first build for almost 6 months with the back left wheel always being the powered one. Back then, I’d swear that it wouldn’t turn when you accelerate or brake, and that one wheel drive was fine. Then, when I got the new enertion motor mount, and put it on the back right(of a different board., I was genuinely shocked at how different it felt: not saying back right is the best, and back left sucks… I just got used to the feel of back right and switching threw me off. Of course I immediately switched it to the left after than… You just get used to it quickly, and automatically correct without thinking. Try switching your dual diag setup to the other side, and see how it feels- it’ll be way different.
also, as far as one wheel spinning faster than the other, @onloop and @lowGuido are correct. Tomorrow I will put a black dot on my skateboard wheels (an old pair I have on one of my normal boards), loosen the trucks, and show it turning slowly. starting with the dots in sync, and then, showing them going out of sync as it travels through a turn.
Also, Onloop’s diagram actually represents skate trucks- not cars
On paper, in diagrams related to automotive tech you are absolutely right. As soon as you introduce a kingpin none of it matters. Just because onloop drew skate trucks on the diagrams doesnt make it a skate diagram…
This concept applies no matter if we talk about cars or skateboards or anything else with wheels that need to turn in an arc.
It also does not matter how the steering system works, wether it pivots on a king ping or each wheels is turned on its own axis or tilts to turn… it really doesn’t matter.
The fact of the matter is the ID of a turning arc/circle has a smaller circumference to the OD.
So even if you just had a one wheel vehicle. For example a monocycle & it had one really wide skateboard wheel of 30cm width. If you make that wheel turn any arc from just a few degrees through to 360 degrees the outside edge of the wheel has further distance to travel then the inside edge…
If you created a machine that spun this wheel in a continuous circle (like a big clock with a wheel assembled onto the tip of the second hand) it would begin to wear out unevenly as one part of the wheel is being forced to travel across an area quicker OR slower then what it is actually rotating.
The thinner the wheel the less it will wear out.
The only way to stop a wide wheel wearing out (if it was attached to the second hand of a clock) is to make the wheel a cone shape, with the outside edge having the greater circumference than the inner edge. This way the outside edge can travel a greater distance in the same time as the smaller inside edge without skidding.