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Gotway Monster 2019

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15 minutes ago, Jean Dublin said:

Gotway announced the new Monster trolley handle is ready, but no details on price yet. 

https://www.facebook.com/groups/AirWheelClub/permalink/2417915808439883/

 

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Well crap... I already drilled holes in my shell and zip-tied on a handle I ripped out of a piece of cheap luggage... ah well... at least mine works and is at the perfect height for me. This thing on the other hand looks like it will end up suuuuuper high!

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:blink:

*rubs eyes*

Do my eyes deceive me or is that a new type of tire tread?!?!!

It is! It's nothing like the tire they've been using on the Monster forever!

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I'm skeptical about how easy the Monster will be to maneuver with that trolley handle at the rear.  I don't even like that configuration on my MTen3.

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1 hour ago, neurokinetik said:

I'm skeptical about how easy the Monster will be to maneuver with that trolley handle at the rear.  I don't even like that configuration on my MTen3.

I know of someone who DIYed a handle similar, it doesn’t interfere with riding, however it is not suitable to trolley such a heavy wheel around. The trolley flexed way too much for my liking

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On 8/11/2019 at 9:36 AM, Hsiang said:

My biggest worry actually isn’t acceleration but braking. I imagine that 15% reduction in torque also translate directly to a 15% weaker braking power, not to mention the additional 20lbs of weight it needs to stop.

I'm not convinced that the larger wheel necessarily results in less acceleration and definitely shouldn't result in less torque. I mean the whole reason we have torque as a measure is to be able to compare forces at different radius' –you know, that's exactly what the definition of torque is 😉

As for acceleration... that really is a function of torque (give or take). Given these wheels have essentially the same 2000W motors in them they should produce the same amount of Nm and there for, I should think, would impart the same amount of work on the road regardless of diameter.

Admittedly the angular velocity will be less for a larger wheel so the larger wheel will be doing fewer RPM but this isn't necessarily a bad thing. In fact, given electric motors have famously flat torque curves (meaning they produce very similar amounts of torque regardless of RPM) this difference shouldn't really be significant. I mean to either increase or decrease the motors RPM by say 15% the same amount of "effort" is going to need to be exerted by the motor regardless of what the original RPM was. 15% more is 15% more.

 

I am willing to acknowledge that smaller wheels may indeed outperform larger wheels but it must be for reasons other than just the distance between the motor hub and the tread of the tyre.

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When people (me included to my shame) mention torque (which you rightly say is constant for the same motor, but really for a given power draw from riding at a certain constant speed), they usually mean acceleration aka "oomph" (that feeling may also depend on the ride mode and firmware). Unfortunately, that's proportional to torque divided by radius (for the same power draw). So here the bigger radius does not help.

But you can certainly accelerate hard on a big wheel (e.g. seated Monster uphills), it will only require more torque, but if you lean it, it has the power. So for the rider, the acceleration might not be (so much) worse on a bigger wheel. It might not even be such a big power/battery draw difference because it's not like you accelerate and decelerate hard all the time so that it would make a difference.

I believe that's the way to see it.

Edited by meepmeepmayer

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4 minutes ago, meepmeepmayer said:

Unfortunately, that's proportional to torque divided by radius (for the same power draw). So here the bigger radius does not help.

I agree with @meepmeepmayer on this one. From the wheel's point of view, it must push against the ground at the wheels outer radius in order to accelerate, so the larger that radius is, the more torque that's needed from the motor. But a 2000w motor is very strong, and the peak watts is probably something closer to 4000w. So as long as you don't over-lean it, it should be fine.

I haven't been able to continue riding and reviewing the Monster V3  because of a leak in the tire, and then we were chased out of town by hurricane Dorian. 

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27 minutes ago, erk1024 said:

so the larger that radius is, the more torque that's needed from the motor

... at the cost of proportionally lower rpm, which balances out to give the same power draw (which is only a natural assumption to compare things).

Ignoring any constants, just the general relationships:

P(power) = T(torque) * RPM (revolutions per minute, angular speed) = F(force pushing you forward at the contact point to the ground) * r(radius) * RPM = F * r * v(linear speed)/r  = F *  v = P

And acceleration is (unfortunately?) proportional to F (= T/r), not T or P.

Works out... for me, I hope it's right.

Also no idea what the motor and electronics characteristics do to this framework.

27 minutes ago, erk1024 said:

and then we were chased out of town by hurricane Dorian

Wow, that's crazy, having to leave home due to weather!

Edited by meepmeepmayer

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3 minutes ago, meepmeepmayer said:

at the cost of proportionally lower rpm, which balances out to give the same power draw

That makes a lot of sense. Interesting!

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I don't actually agree. While I agree that a smaller wheel will "push" on the road with more force it also "travels" a shorter distance by the exact same amount.

I appreciate that if you were to hold onto the wheel with your hand in an attempt to stop it from turning while the motor tried to "pull" it around you would have an eaiser job of holding the thing steady on a larger wheel. This is clearly evident but it is a mistake to assume that the "harder pull" of a small diameter wheel will result in a faster acceleration. While it is true that the apparent force is greater on the smaller wheel it is important to remember that that force is being applied over a correspondingly smaller distance and the net amount of work being output is exactly the same.

When thinking about this it is easy to fall into the trap of imagining a given amount of rotation (lets say 3°) and conclude that given the smaller wheel will achieve this 3° more readily it will there for provide more acceleration. The fallacy being thinking that the two 3° rotations achieve the same output. While it is true that the smaller wheel achieves the 3° rotation more easily (ie. more quickly) the actual surface of the wheel itself doesn't move as far as the larger wheel would have if it were to achieve the same 3°. The (possibly un-intuitive) result is that although the larger wheel has to "work harder" to achieve the same amount of rotation that extra work is "rewarded" with additional distance in exact proportion to the amount of that "extra effort". The other way of looking at it is although the larger diameter wheel will achieve fewer degrees of rotation for the same amount of effort (ie. same amount of time) those fewer degrees will translate to exactly the same distance, and therefor have exactly the same amount of acceleration. The result of all this is that the acceleration of the wheel is primarily driven my how much power the motor can deliver and is in fact independent of the wheel radius.

Now, it's true that all motors have optimal ranges of operation and although generally speaking electric motors have fairly "flat" torque curves they will non the less still have optimal ranges over which they work best. It may well be the case that the higher RPM of the smaller wheel puts it in more of a sweet spot for the motor but the additional acceleration is actually coming from the more efficient running of the motor rather than anything to do with the radius of the wheel.

There are of course other issues to consider such as peddle leverage, wheedle mass etc. which will also contribute to the "agile-ness" of the wheel and what I'm proposing is that it is actually these things that are making the difference rather than wheel diameter per se.

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@Slartibartfast You could be right about the overall acceleration. For the moment, let's ignore the angular momentum of the wheel itself because it's not such a big change in radius, the MSX has a 19.5" (outer diameter) x 3" tire instead of the Monster's 23" (outer diameter) x 2.75" tire, and in both cases the tire is not that heavy compared to the massive (especially in my case!) rider. 

If we ignore the angular momentum, then the power output of the motor should accelerate the mass of the rider at the same rate in both cases. If the motor is putting out 3000 watts, then you should get 3000 watts worth of acceleration out of both the MSX and Monster. Right? If not, you'd have to explain how a portion of that 3000 watts of power was disappearing.

 

Edited by erk1024

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2 minutes ago, erk1024 said:

If the motor is putting out 3000 watts, then you should get 3000 watts worth of acceleration out of both the MSX and Monster. Right?

Yes, that's exactly what I am saying.

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Per the free-wheel speeds, the MSX is just a little faster and yes it has a smaller diameter wheel.  This IMPLIES my theory that the Monster has a different motor winding arrangement, maybe different number of permanent magnets, etc.  Assuming similar batteries, wire-sizes, same firmware with diff configuration/adaptation ...

It appears the Monster has been re-configured to keep the torque and acceleration similar to an MSX (rather than a faster monstor with otherwise same characteristics).  Why?  My GUESS is that the larger wheel w/ same motor would 'feel' more sluggish at starts and slow.  Also, I don't know anyone regularly doing EUC riding above 35 mph.  Seated would be easier to go faster due to the rapidly increasing wind resistance over 30 mph. 

POV references:

  1. I have a 100V MSX (19") and so far my fastest speed was 33 mph.  I've lift-tested its last-alarm speed is 42 mph and cutoff varies between 56 and 59 mph. 
  2. My e+ (16") is much quicker/nimble/maneuverable than the MSX even though its only rated 500 W.  I still favor it for slower riding like with dogs, people, or while playing guitar at a tailgate party.

Disclaimer:  I'm actually an engineer so I'm probably wrong. :D

 

 

Edited by Elliott Reitz
tweek clarification, + a selfie vid :D

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Fun fact for tech nerds after dissecting my burnt 2460Wh Monster 3:

Monster 3 is wired +1 +2 -4 -5 on the charge port with 18AWG silicone wire.  It can DEFINITELY take 10A if you have a charger wired properly for it.  

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How much miles did you get on a full charge? 

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Just saw these specs posted by Gotway, so the monster actually has a 2500 watt motor vs the 1900 watt in Nikola and MSX??

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Edited by photorph

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On 8/26/2019 at 11:09 AM, Jean Dublin said:

Gotway announced the new Monster trolley handle is ready, but no details on price yet. 

https://www.facebook.com/groups/AirWheelClub/permalink/2417915808439883/

FB_IMG_1566814164781.jpg

Review

Today I received my original trolley handle and seat. 

The parts holding the handle are made of metal, I thought they would be plastic, so that's a good surprise. 

When sliding the metal holders in, there is a resistance point due to the "screw" within the handle at the bottom, that made me scratch a bit the black paint of the white trolley (black metal would have been better). 

I scratched it further when trying that it still went out smoothly while still not fully screwed, so the part that shouldn't move, moved and got scratched with the holders. 

It works as expected, only think is that it's a bit stiff to pull out and put back in once screwed in place (not when unscrewed, it goes out easily and smoothly then), however many models have trolleys like that which are hard. Still, better than pushing it around (mainly without the seat). 

It is sturdy, it doesn't shake as other handles I've seen, which is good. 

Sure it's still a back handle and not centered as other EUCs, but still much better than no handle at all, mainly on a wheel as heavy as the Monster. 

It has 3 locking levels, high and medium are good for me, low is too low for me. The high one is not as high as the 18L/XL handle, no need to be that high in my opinion, it is just right as is now. 

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---

I also installed a DIY Mudguard made by cutting a Front Flexible Mudguard for bikes.

8LICc7I.png

Video of it and pictures of how it's made on this link http://imgur.com/a/greDs3l

If anyone is too lazy to make one, I wouldn't mind doing and sending them anywhere worldwide by standard lettre, for €15 all included.

Ready to install (only need to peel off 2nd side of the strong elastic double sided tape and stick in place. 

But I suggest you do it yourself, it's easy. 

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1 hour ago, Hsiang said:

Ran into problem with loose axle but thanks to @Rehab1 its fix now I think....

 

Cool video 

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1 hour ago, Hsiang said:

Ran into problem with loose axle but thanks to @Rehab1 its fix now I think....

 

Thanks for the mention! Glad it worked! :thumbup:

Awesome video as always!

Edited by Rehab1

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10 minutes ago, Hsiang said:

Thank you! It worked but I think I need to use some loctight since I can feel it loosen up a bit since I tighten it on Friday.

Btw I did a long range test yesterday and was able to cover 54 miles and still have 34% battery left. The range on this wheel is pretty amazing.

This is really strange that it's loosening.

One suggestion, after watching your video. I don't think you're tightening it enough. I think you saw my video. Did you see how much force was applied? When I viewed your video it did not look like your Monster pedal hangers were secured in an immovable object (vice) as you tightened the nuts.

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On 9/19/2019 at 1:46 PM, Jean Dublin said:

I also installed a DIY Mudguard made by cutting a Front Flexible Mudguard for bikes.

8LICc7I.png

Video of it and pictures of how it's made on this link http://imgur.com/a/greDs3l

If anyone is too lazy to make one, I wouldn't mind doing and sending them anywhere worldwide by standard lettre, for €15 all included.

Ready to install (only need to peel off 2nd side of the strong elastic double sided tape and stick in place. 

But I suggest you do it yourself, it's easy. 

The mudguard works great. 

I had to go to the shop again today, so I took the change to get another two and cut/bend them and add the strong double side tape to have them ready for anyone who needs one, just let me know if you want one ;)

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As you can see on last two pictures, you can adjust how close to the tire you want to mudguard to be, just by pushing it down or up where the plastic is bent. It stays in place then. 

15€, worldwide shipping included, or make your own! It's easy :)

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