It would essentially be like splitting PPM for 4wd, except one of the split is only to servo control. Servo motion directly correlates to brake position, therefore brake power can be mechanically tuned by a preload spring. Power is fed by DC-DC converters independent of the vesc. It will be identical to the brakes used on nitro engine RC cars. It is not a replacement to the VESC brake, just a supplement to it as 2WD braking is just not strong enough even at excessive amounts of regen.
Ok, it seems to me that this is a non-problem and using a servo with that kind if setup is making it more problematic. Iām not saying thereās anything wrong with the pursuit, just donāt understand the need as Iāve never had breaks be an issue, even with my limited 4WD experience.
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Theres a lot of variables comparing bike to eboard free-roll.
Wind resistance can be much more on a bike.
The diameter of the bike wheel makes for lower rolling resistance on anything other than the smoothest surface
The rolling resistance due to the bike tire and tube vs HIGH rebound pu ā¦I wonder
The mechanical loss of the bike freewheel and wheel bearings vs bearings and always-connected beltā¦the bike bearings donāt have to spin nearly as fast so less resistance that way and the belt is surely more of a loss than a bike ratchet freewheel
Eddy currents and hysteresis is a pretty small loss for 12 tooth motors spinning at relatively slow speeds. A pulley n belt with a 3:1 gearing will have 3x the hysteresis and 3^2 or 9x the eddy currentsā¦but still this resistance is not that much
I think the biggest decrease in free-roll on an eboard is cogging torque: the pull of magnets away from the stator teeth.
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I think if you want free rolling you should go for a clutch so you can fully disengage the drive that could be re-engaged for regen. Somehow seems less complicated than brakes + one way drive .
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Flashback to me bailing into rocks as my board picks up speed with the brakes full on and the back wheels skidding down the dirt trail. 
Or the one where I body slammed the back of an SUV after it slammed the brakes and my -50A of regen barely kept me from going through the car.
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Yeah pretty much. Regen brakes are != hydraulic brakes. Not in esk8 anyway. Plus you have the benefit of full brakes on a full charge going downhill.
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Iām suggesting that at -50a in 4WD your issue may be something other than breaks. That should be full stop.
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A small note about free roll, I noticed a huge difference after going from 84mm fly wheel clones from Torqueboards to their lovely 110mm. When going downhill, my board doesnāt slow down at all now, where it would slow down with the smaller wheels. I changed the deck too but I doubt it changed something in that matters. All the rest is the same (belt, motor, battery, VESC configā¦).
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I think momentum plays apart in bigger wheels. Simple test is to put different sized wheels on the same push board with the same bearings and roll them all by hand - the difference is marked.
N more leverage against all the resistances with bigger wheels.
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In relation to wheel sizes;
More torque = more rolling resistance?
Less torque = less rolling resistance?
Itās a combination of the really high speed gearing and I just tend to command a lot of the brakes. My stopping distance from 35-0 at -50a is shorter than my bamboo evolve from 25-0, but its still no match for high power hydraulics.
Iām fairly satisfied with -50, a little bit more would be nice but itās strong enough. But for 2wd boards, rear wheel only braking just doesnāt quite cut it. Most you can do is skid the back wheel which has not much braking power
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As someone who has pushed far to many vehicles of various sizes much too far, this statement is fundamentally incorrect.
A car or bike in neutral is functionally disconnect from itās drive train, and the drive train offers essentially zero resistance.
This is not only NOT the case with electric skateboards, the real issue is that the other item that remains connected is the motors. Electric motors. And one fundamental fact, a physical principle of electric motors, is that as the electric windings in the stator travel past the permanent magnets in the rotor, they generate a magnetic field, and that magnetic field is opposite that of the magnetic field on the magnets in the rotor, age that introduces massive amounts of drag. THIS is why free spin of electric skateboards is so awful, and why it is MUCH worse than that of cars, bikes, or any other similar vehicle.
Not quite.
The cogging torque you feel alternates drag and boost which cancel one another out. The magnet slows the rotor slightly, but then speeds it up the same amount. Thatās the cogging. Itās a net zero torque over a full rotation. The only resistance in the motor is due to bearing friction and, at low speeds, a negligible amount of iron loss, and a negligible amount of wind resistance.
Most of the resistance you feel is from the belt transmission.
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