Hey guys, I was testing some builds in the calculator and came to the conclusion that I don’t know how much torque is enough torque.
I’m basically comparing with similar builds to have an idea but nowhere in the forum could I find a number (in Nm) of a good value to aim for.
I understand that torque is highly dependant in my weight, ride style, road condition, etc. But even so, why aren’t people using the actual numbers when talking about this stuff?
It doesn’t matter how much you have as it can be limited in vesc setting through motor amps. The higher the better though as it gives you adjustability
The more the better. As long you still have the speed you want you can always module the torque. While in case is low you can not do anything about it.
I understand, but you have limited resources. I might consider having a lower top speed to have a good torque.
Most people here tend to choose more torque over speed, as you’re better off being able to climb the average hill at a reasonable clip rather than being limited to going fast only on flat gradients. That being said… if you happen to be riding west and you see the sun rising toward you, indicating a reversal of the Earth’s rotation under your wheels… maybe consider toning it down just a smidge?
If you’re doing stationary burnouts on dry asphalt, you have too much torque.
Also, that would be amazing.
Or different gearing
@Gustdd, am a big guy. When i build my board i was 150KG (+320lbs) and was concerned about hill climbing capability so i made sure i geared for torque over speed.
I have a dual 6374 190kV 2.85:1 reduction (37 to 13 pulley) and 90mm wheels. According to https://calc.3dservisas.eu this give ~30mph top speed but should provide about 22Nm max torque after reduction and i can personally verify that this is a metric shitTon.
We have some fairly steep hills where i live and i have never had a problem getting up any of them. Additionally I have only ever reached full power a couple of times as this much torque will easily throw you off unless your fully prepared for it. Even at my weight i could go 0-20mph in ~2 secconds and that was not at 100% power.
Honestly I believe that for most riders this is far to much torque. my extra weight allows me to get the grip required but friends that have tried my board struggle to stop the the wheels slipping under power or breaking.
I agree that Total Max Torque is not discussed often but is a usefull metric. I would be interested to know the TMT (did i coin this abbreviation?) for other peoples boards and see how different setups compare.
What are the 6374 kv ratings?
Now, this is good information. I’m using AT wheels so I might need a bit more torque.
Can we get Ken Block to try this?
Somes graphs I’ve made a while ago, not an exactly value but should give you and idea
Torque is this case is for 80mm wheels, a better way to talk about thrust since it is independent of wheel size
I wish I could do real burnouts without cheating!
Being serious, I ride a Kaly build with a 12S4P Samsung 30Q pack, dual 6374 190 kv motors, 4:1 gear drives, and 8in pneumatic tires and I feel like I could still use more torque when I’m not on pavement. I end up going full throttle quite a bit.
And more traction, but that’s a separate problem.
That’s not a real torque oriented setup 
Isn’t the better question how much acceleration is to much? The build I’m working on has 18Nm on 90mm wheels but it will throw me because I’m only 70kg with a board, but for other people it would be fine. Is accelerating at 60% of freefall to much? In theory it’s twice the acceleration as @ducktaperules setup even though it’s less torque, but I’m also only using a 4p 30Q battery so I only get 60% of the torque, or can I pull 32A from a 30Q for a second?
Yeah man, it seems like there could never be enough torque and top speed. I have a 13s at 100motor and 50 batt 6374s and I could still not get enough torque or top speed. But I do have a bunch of guys in NYC that want to copy my build…
I guess that Torque is maybe not the best metric because it doesn’t account for wheel diameter.
Remember : Torque (Nm) = Force (N) * Distance (m)
If we compare my builds to @tenshi0’s we both have same Voltage, motors size / kV.
My build has 2.85:1 reduction producing 22Nm Torque but with a 90mm wheel that is 490 Newtons of force.
@tenshi0 has 4:1 reduction producing 32Nm Torque (50% more) however with a 8" (203mm) wheel he only gets 215 Newtons of force (55% less).
With these builds the board with 50% more Torque actually produces 55% less Force to push the user forward.
I think @ZachTetra is right that we should think in terms of acceleration.
Acceleration = Force / Mass
For me that means 490N/150KG = 3.2m/s/s forwards (1/3 gravity). During this acceleration im experiencing 5% extra gravity and an 18 degree shift forward in my balance.
If my 70KG friend tries out my board then for them the same board accelerates at 7m/s/s forwards (70% gravity). During this acceleration hes experiencing 22% increase in gravity and an 36 degree shift forward in balance.
Personally i think that Force is the important thing when considering overall gear ratio to the road, but its the acceleration that throws you off. Thoughts?
EDIT: just did the maths and using the calculated 3.2m/s/s acceleration at full power my 0-20mph time should be around 2.8 seconds. Feels about right . . . Ive only ever been brave enough to do it a few times. For my 70KG friend he would be able to do the same 0-20mph in 1.24 seconds . . . assuming he had enough grip to put that power down and could hold on strong enough.
Haha! Never said it was. Just thought I’d provide a frame of reference if anybody was curious.
And, I did say I wanted more torque, didn’t I? It’s just tough to get enough torque, ground clearance, speed, and not have a 500lb monster of a board.