Many of my customers have asked me to start stocking motors for my boards so we ordered some Maytech motors for testing. Maytech seems to be producing the best quality and specs, time and testing will tell.
We have a pair of 6355 270kv motors coming. These motors are rated at 3250 watts max!!!
People are going to hate me for this but they will come with 10mm shafts. It is the next logical step in drive train development. A 10mm shaft can handle higher loads and will have fewer cases of a pulley or motor housing stripping free. And yes, I will also have 10mm pulleys available.
We will not be rebranding the Maytech motors. For the sake of the sport I think total transparency is needed to properly assess the performance of the motors currently produced from different manufactures.
We chose the 230kv model for initial testing because it had the highest max watt rating in the series but the motors can be customized to other KV ratings. 230kv seems to be the sweet spot for max output for this particular model.
This is what their smaller series looks like. I will post some photos of the test units when they arrive, they should look similar. We are having them redress the logo too.
Just be aware that with 10mm shaft diameter with 3mm key basically rules out using 12T & 13T motor pulleys with 5mm pitch.
It also makes 14T pulleys borderline viable - as there would only be around 0.90mm of pulley body from the valley of the pulley tooth to the top of the notch which houses the key. I think that would compromise the structure of the pulley.
15T pulley might be ok as it will have 2mm of material remaining, which should be ok if the pulley is made from steel.
is there any evidence of 8mm axles bending under the load of an eboard??
@onloop Our aim is the performance market and to use the power these beauties can deliver so no issues with not being able to use anything less than a 17 tooth pulley. I find that anything around 15 tooth or less to cause problems when braking. We will have lower KV options for lower speed builds or an offroad board.
The switch to 10mm has more to do with the amount of power transfer we are dealing with. No sense in bottlenecking all this power with an 8mm shaft.
On an e-board as we know it, shafts are only marginally subjected to dynamic flexural stress induced by belt tension, which cannot be very high as we don’t use tensioning devices. I don’t think bending a shaft is a realistic failure mode, it will more likely snap, especially if the shaft is inferior steel quality, which wouldn’t surprise me on cheap Chinese motors.
Shaft diameter is typically dictated by torsional stress, induced by motor torque an thus the power of the motor. However, the absence of any real torque curve data for our hobby motors leaves us guessing. So IMO bigger=better.
Looks good 6mm motor shafts can snap. I have snapped a SK3 50mm 280KV motor shaft however this well over 1k+ miles. It also hit a pothole pretty bad which is why it snapped.
WTF?.. how come everyone is talking about 6mm now? it’s confusing… stop it.
the Op said
The switch to 10mm has more to do with the amount of power transfer we are dealing with. No sense in bottlenecking all this power with an 8mm shaft.
skateboard trucks have 8mm axles! so do many brushless outrunner motors! saying that an 8mm solid steel shafts is a bottleneck in terms of torque transfer ability - because they might snap? that’s a bit far-fetched… I have never seen or heard anyone say they have snapped an 8mm shaft! Those guys in the video I posted are landing HUGE tricks and rolling away on 8mm shafts…
There are plenty more bottlenecks before we need to over-engineer the shaft…
The belt which transfer the torque is definitely the weakest link
The motor mount itself, some people have aluminium motor mounting plates with cross sections directly next to the motor that are under 6mm! aluminium is going to snap before an 8mm steel shaft will snap!
Spruiking the 10mm shaft as an improvement of an 8mm shaft is a long stretch of the marketers imagination!
For instance what does this mean?
“fewer cases of a pulley or motor housing stripping free”
These maytech motors are crazy. I was looking on their website and found a 6374-330kv motor that has an output of 3200 watts. This would be an awesome single drive motor. I will have to look into them.
@trbt555 Understands why 10mm shafts are used on these motors I bet the engineer who designed them also knows a thing or two about torsional stress. It is easy for most people to see that we can exert more force on a pulley or motor housing using a 10mm shaft vs 8mm or “6mm”.
8mm will work fine for the average board with a top speed around 25mph but many people have issues with the motor housing spinning free from the shaft. With a 10mm shaft this will happen less frequently or not at all, testing will tell.
Our truck axles are not under the same torsional stress that our motor shafts experience. Completely different modes of operation actually, torsional versus flexural. Even a child can see that a 10mm shaft will handle torsional loads better than an 8mm shaft. Many people have experienced torsional failures and remedied this by replacing the grub screws with oversized bolts so pretending like this is not an issue is a disservice to the sport.
To say 10mm shafts are a marketing ploy is laughable. I’ll be sure to let the engineers at Maytech hear that little gem.
So now lets put the whole bent shaft argument to bed and get on with this!
These motors will be arriving in about 2 weeks. I should be all caught up on builds by then since I have an apprentice helping me out around the shop. The plan for these motors is a 40 to 45 mph top speed. We are going to gear it for a 50 mph target speed, 17/36 tooth on 90mm wheels @12s. The pack I am designing for this build will have a max constant output near 8000 watts using 30amp high discharge 18650 cells. Expecting to use around 3000 watts max.
We have one of the larger 150kv 6374 motors coming too. It will go on a single motor build with more rational top speed. Shooting for 28-30mph with same drive as the dual motor build.
I’m curious as to how a 10mm shaft will mean that a motor is less likely to fall apart?
If you are worried about the barrel coming loose (which you won’t need to with maytech) why not modify the design, instead of a flat spot on the shaft & an M4 set screw you could consider a key/keyway at that end. Or have a through hole in the shaft and bolt straight through it. That would be a viable mechanical solution to prevent the issue you seem to be having with your motors that fall apart. I suppose to be transparent we all should know what motors you are using that are falling apart?
My point is that a 10mm shaft is not necessarily going to magically make this better… In fact increasing the diameter of the shaft is increasing the length of the lever, it increases the leverage & the load at the fixture! so the force at that point where the set screw engages with the shaft will now have a greater force being exerted onto it. It could actually make the problem worse.
Also, once at high speed the torsional load one the shaft is minimal, torsional load peaks during acceleration & braking and that load is determined by the load the belt can transfer which will max out before the breaking point of an 8mm shaft.
If you plan to use a chain maybe then a 10mm shaft is better…
Don’t get me wrong! I 100% agree that a 10mm shaft is mechanically stronger than 8mm for torsional torque loads. That’s it though! It won’t solve issues that arise from poorly assembled motors.
It’s my opinion that If you have problems with motors falling apart you just need better motors with better construction quality made with better materials… Maytech is definitely the best…
