Pedal Tilt-back

[AlanR]

Decided to check my speed when riding my EUC as I felt I was having pedal tilt back too early!   Using a Garmin GPS I found that it is happening at about 12 to 13 kph despite the specs saying max speed is 18 kph! I have a Dragonmen Hotwheel with a 350 kW motor.  

Also, I read here about 'face-planting' on over speed; does this mean the wheel locks up rather than free wheeling to a stop?    Is it prudent to limit speed to say 70% of max-speed?

[WayneZengAU]

A max speed of 18Kph means that the wheel can only reach that speed with maximum tilt back. Given that most EUCs actually exaggerate their top speed, it looks like your wheel simply begins tilting from 12 kph and restricts you from speeding any more at probably 15 - 16kph. 

Face planting above top speed refers to the motor cutoff occurring as a result of your wheel not keeping up with your forward lean due to motor inadequacies or software issues. 

[Gimlet]

You'll eventually find that the option to "freewheel to a stop" doesn't exist as once the motor stops powering you there is nothing to keep you balanced.

[esaj]

Decided to check my speed when riding my EUC as I felt I was having pedal tilt back too early!   Using a Garmin GPS I found that it is happening at about 12 to 13 kph despite the specs saying max speed is 18 kph! I have a Dragonmen Hotwheel with a 350 kW motor.  

A max speed of 18Kph means that the wheel can only reach that speed with maximum tilt back. Given that most EUCs actually exaggerate their top speed, it looks like your wheel simply begins tilting from 12 kph and restricts you from speeding any more at probably 15 - 16kph. 

Pretty much each and every 14" generic says it's top speed is 18km/h (I guess they mostly use same mainboards and motors), nowadays it seems there are generic 16" models available with higher (advertised) top-speed, don't know about those. On mine, it's the same, it starts the tilt-back at 12km/h and the top speed is maybe 15-16kmh, that seems to be true for most other generic users also.

[AlanR]

OK thanks @Gimlet and @esaj, I notice you both have several EUC in grey text at the bottom of your comments - are these units you have or have used? Also they mainly quote the battery capacity - Wh - isn't the motor power as important? What specs would you recommend for a good second EUC [and without over speed cut-out]?

By the way, I pumped my tyres to 50 psi  from 40 and it feels much better riding!

[esaj]

OK thanks @Gimlet and @esaj, I notice you both have several EUC in grey text at the bottom of your comments - are these units you have or have used? Also they mainly quote the battery capacity - Wh - isn't the motor power as important? What specs would you recommend for a good second EUC [and without over speed cut-out]?

It seems to me that the rated motor power isn't THAT important, as my measurements have indicated that the peaks can and will go (momentarily) way above even the nominal peak power of the motor (above 2.5kW on MCM2s on a steep gravel hill, the motor rated power is 500W and nominal peak is something like 1.5kW). I've ridden that hill up (it's really short) with a 350W generic too, at a crawl speed (it couldn't take my friend up the hill, who weighs closer to 15kg more than me). And probably now knowing how much power it requires, wouldn't try it again in fear of burning the motor or frying the mosfets of the mainboard. The motor-rating seems to mostly just tell what kind of powers the motor was designed for, so at least in that sense bigger is better, as the motor can better handle the high power peaks without overheating.

For second EUC, pick some "name-brand" known for higher quality than generics (the most "known" around here seem to be IPS, Ninebot, Solowheel, Kingsong, Gotway... there are others, but I haven't heard much for example about the Rockwheels or F-Wheel Dolphins), the tire-size you're comfortable with (bigger is also usually heavier, and less maneuverable on tight spaces, but more steady in high speeds and with bumps/pot holes). Preferably the battery size should be above 500Wh (typically >= 528Wh), as that means there are four packs. More packs = less stress per pack, less voltage sag & higher continuous max and peak current = more power, more torque. Less likely for you to overpower it and it won't stall on steep hills. With higher motor power rating, you can be "more sure" that it can take the high peaks (and I think the firmware for higher rated motors also allows the wheel to use more power without tilt-backs or such?).

EDIT: All wheels have some sort of over-speed cutout at some point, if not for BMS or mainboard cutting out, the wheel will fall forwards after it reaches the maximum RPM, where the torque drops to zero and it simply can't keep you up if you're leaning forwards, we can't break the laws of physics    The only way to stop this that I know of, is to prevent the rider from going too fast by tilt-back (and even then you can probably still out-lean it, if you insist ).

The rest is probably up to your personal preferences, tilt-back or not, max speed, ride comfortability, wheel design...

 

By the way, I pumped my tyres to 50 psi  from 40 and it feels much better riding!

I prefer higher pressure also, between 50-60 psi usually, but I'm lightweight, don't know if it's too high for heavier riders.

 

[Jason McNeil]

Airwheel still maintain that 12mph is possible with all their eWheels; this is not an exaggeration, but a proper lie, even under no-load, on a treadmill, the pedal-tilt-back is unrideable at 10mph. https://www.youtube.com/watch?v=-vSymnoz5-Y  

[Chrisxr2]

Airwheel still maintain that 12mph is possible with all their eWheels; this is not an exaggeration, but a proper lie, even under no-load, on a treadmill, the pedal-tilt-back is unrideable at 10mph. https://www.youtube.com/watch?v=-vSymnoz5-Y  

I agree that would be impossible to stand ion, dont you need to do the test with a person onboard to make it a fair test though??

[PedalFaster]

Any test where the wheel is fastened to something stationary (such as the tester's hand) has a fair likelihood of being meaningless.

First, we have to figure out why the wheel is signalling for a slowdown:

1.  A software rotational rate limit has been exceeded

     2.   The motor inductance means that little torque (/safety margin) is available at such a speed (unlikely absent bad design)

     3.  The work being done to maintain this speed approaches the limit of the power which can be delivered on an ongoing basis by the motor or the battery

A treadmill test can possibly evaluate #1 or #2, but it cannot without extreme difficulty evaluate the most important case of #3

Think about what the work is being done on.  In the real world, it is being done to combat air resistance, bearing and rolling resistance losses that depend on the rider's weight, and possibly to raise the rider and euc up hills.

In contrast, on the treadmill very little work is being done to fight air resistance, bearing losses are minimal since the weight is only that of the euc itself, and the system is neither gaining nor losing altitude.    In short, most all the work being done is being done against the artificial load of the treadmill, and there is no indication that such load has been programmed to accurately model actual riding.  In fact, it would be quite difficult to design a treadmill which would do so.