ERider 8000W scooter - Australia (similar to xm5000li)

My Thunder has a low-speed shimmy problem, somewhere in the region between 5 and maybe 20km/h. But it only occurs if I take one hand off the handle bar, and it is just about gone with the heavier IRC Urban Snow winter tires instead of the original Cheng Shin. That is the reason why I wrote that a reinforcement of the frame itself may be necessary to increase it's torsional stability. Thunder with the very high center console should have a far more sturdy connection between steering head and the rear end of the bike than a step-through scooter like the Lightning / VK2008...
One thing the Thunder surely does not have is too little trail. The head angle is considerably bigger than on most other scooters, more like a chopper motorcycle. What reduces trail a little is the fact that the bridge holding the telescopes is V-shaped instead of straight across, thus placing the telescopes slightly forward of the steering axis and reducing trail. Fork rake I guess.

HOWEVER, all of this shimmy stuff has NOTHING to do with the front suspension being clearly under-damped and bouncing up and down during heavy braking. To the point of the front wheel lifting off the ground!?§^!!! That is what needs to be addressed IMMEDIATELY!!!

The shimmy problem needs more than just an explantion, it also requires action on behalf of your frame supplier Xinrongzhou Vehicle Business.

Mountain, you wished us a safe ride. But you also need to ensure that the products which leave your premises are safe in themselves. How Thunder with this bouncing issue could ever get an EC certificate is beyond me...

You wrote before that the Thunders of 2011 has different rear shocks than the 2010 - have they changed the front ones as well ?
I only did one hard brake test, but did not notice any of the behaviour you described. However, it was not an "panic brake" which is of course even harder.

Or could it be a production quality problem - the bouncing you describe could potentially come from a worn or loose bearing, or a weak front end of the frame right ?
A damper that is too soft may produce bouncing as well of course, but then it it usually a matter of leaking oil or something like that (i.e. the spring is almost undamped). You'll have to report to us once you have chnaged oil in your shocks if the situation improved.
In the case of poor dampening, it should be fairly easy to correct in the factory, a better shock absorber or a better adjusted spring vs absorber could probably do the trick ?

/K

Yes, 2011 rear shock comes from Taiwan company who is main supplier of HONGDA,it is real shock absorber instead of SPRING,the feeling is great improved compare with chinese shock !

but they don't have suitable size for our front shock. And our quantity is too small to attract their interesting on development.

I now have 1579km without a problem and hit a new GPS certified top speed of 95.4km/h. That was too damn scary! And a waste of Amps.

Scary? I'd LOVE it :-) But it does take some getting used to.
As for the guessometer, mine shows whatever, and starts blinking the last bars out of the blue, so I cannot in any way report similar observations of apparent learning. However, as you have a true PDT scooter, who knows how exactly that guessometer is connected to the rest of the bike... It MIGHT actually communicate with the magic CAN box and be tought from there. I am sure IFI Motors could enlighten us, I think he already commented on that.

I now have 1579km without a problem and hit a new GPS certified top speed of 95.4km/h. That was too damn scary! And a waste of Amps.

Scary? I'd LOVE it :-) But it does take some getting used to.
As for the guessometer, mine shows whatever, and starts blinking the last bars out of the blue, so I cannot in any way report similar observations of apparent learning. However, as you have a true PDT scooter, who knows how exactly that guessometer is connected to the rest of the bike... It MIGHT actually communicate with the magic CAN box and be tought from there. I am sure IFI Motors could enlighten us, I think he already commented on that.

Or maybe mr Moutain Chen can point us to more information about the guessometer?
If is as lousy as they first rides shown i'd actually would like to know how it is supposed to work. Maybe i can calibrate it or something?

/k

Klas, you have a voltmeter on your display as well right? I would use this for now. Maybe later you can add a Cycle Analyst.

I went out for a ride today and tried to brake as hard as possible with the front brake. I didn´t notice any abnormal behavior.
I will try to balance the front wheel and see if this helps getting rid of the vibrations at high speeds.

Good to hear Johnny that your Thunder seems o.k. from the shocks side at least! The big problem with shimmy and other resonating vibrations is that it can sometimes be caused as well as stopped with minimal changes in stiffness and / or mass in certain areas. A shimmy could maybe be stopped by adding a small weight to the end of the handle bars, thus changing it's natural frequency to no longer coincide with that of the front fork or the frame. And the main cluprit concerning braking shudder is usually play in the steering head bearing or uneven brake discs. In my my case the brake disc is completely aquitted, it runs smooth as silk, and the reduction of steering head play took the shudder out of all but the most violent braking. THAT is qutie clearly a problem with too little / too thin damping oil in the shock absorbers, but there also was some minor damage to the telescopes in the new state already, which is why the fork replacment is a warantee thing that we HAD to do now. My dealer's Fury/Thunder that I currently ride until mine is done got rid of the braking shudder by minimising the steering head play alone.
It appears that the front section of Thunder is boderline in many aspects of motorcycle stability - some work just fine, some suffer from high speed shimmy, some from low-speed shimmy, some from too much steering head play (that one is the easiest to cure in Mountain Chen's factory already), some from insufficient damping, some from torsional frame instabilty, some from too weak telescopes or too much play in the telescopes, some from an unbalanced front wheel...

...double click on save button...

Hi
Sorry to reply late, I am on a business trip (Belgium buss Expo, after Spain support and training our importer Bereco)
Concerning the green Led of charger the green sometime comes on and its just a regular check of the charger it will turn red after a second. A full charge is when charger is green constantly.
About the battery meter we do monitor the current going out and with battery voltage and action estimate battery condition. Its not a 100% correct but its good until we get a full BMS.

Thank you for this info, explains alot!
Stearing head play is very common on chinese scooters and we also had quite many taiwanese EVTs with this problem..

I did my first morning commute on the new bike this morning.
Overall a pleasant experience, apart from the 1 deg C temperature, brrr.

The Guessometer, said 2 bars immediately when I turned on the fully charged scooter.
The whole trip (~10km) I got around 74-75 Volts on "idle", and it went down as low as 66V when using the accelerator heavy.
Which I only dared to do a few times because of the temperature and possibility of ice on the road, although they were pretty dry...
I do appreciate the recommendations to get a CA (maye I will), but first of all I dont know where to put it (it is pretty tight with space up at the dashboard). Second I am an EE engineer, and thus like to tinker with stuff, so if I can get hold of how the Guessometer works, maybe I can get it to work better, maybe even connect a shunt (unless already there) and see the amps as well. I would also like a clock and a temperature meter (road AND battery) - but I may go for the same option as on the moped there and use a cheap external one, although it is another thing to clog the dashboard....

I am not a hardcore rider, as MERoller seems to be, so I will not use the scooter during the winter, and we soon expect the first snow here in Stockholm (it usually arrives early in November, goes away for a few weeks and then arrives again in December/Jan to stay until March-April). But I just had to try to commute with it at least once before the winter :)

Remember, for reference, that I used to ride a 45km/h electric moped for the last year, but I do have a motorcycle license and own a Suzuki DR650, which I unfortunately dont use as much as I would like.
It was really nice to be able to speed away from the red lights in silence, and keep the speed limits rather than sitting with the throttle at full the whole way (regardless if it is 50kph or 70kph speed limit) watching all the cars pass by.

I also noticed what MERoller and Johnny_J has remarked at, the low beam is really low ! I'll look at this during the winter and try to raise it a bit to at least see more than 5m ahead of me. I even think that at the current setting I woulnd't even pass the MOT/TüV, which isn't necessary in 4 years though, since it is a new scooter.

I am also thinking if I could wire the high and low beam together at the high beam switch. As it is now the low beam goes out when the high beam goes on, UNLESS you use the "pass" button, then both are active. And in a High beam setting I do want as much light as possible. I just have to check whether it is legal to use it that way (but I do think it is, some cars use both beams I think)

The shaking was there today as well, although I experience that it subsides a bit after a while, presumably after the tyre has warmed up a bit, so it is probably a balance problem or a tyre problem.

/K

I think the most favourite thing is when active BMS installed,connect USB to your notebook and reading the flash small arrow jump here and there , showing the current balance between cell and energy move here and there when charging and discharging....

Do the BMS for the thunder have a USB connection, and in that case can I find the program for it somewhere ?
I think I have the Thunder with the GBS-LFMP cells...

/K

Just wanted to let you know that I went to a scooter shop today with my front wheel to get it balanced and they told me it was very much out of balance, they had to add 45g to one side which is very much according to them.
I haven´t tried the scooter yet, propably tomorrow, will let you know how it works out.
It´s a shame this is not made in the factory, strangely enough the motor has some balancing weights on it. The scooter guys said that normally it´s the front wheel that really needs balancing, not the rear...

Well I just placed my order for a pair of 720p video recording sunglasses at deal extreme. I also got an 8gb card to record the movies to. All for just $55. Pretty good. I was quoted around $299 at a shop here in Australia for what looks to be the same product.

So when I get the glasses I will be be able to SAFELY make more videos while riding the scooter.

Thanks again Phil for all your video efforts, your work is greatly appreciated! Sifting through youtube for video evidence of how such an electric scooter operates in real life was one of the first stops I made when I began my research on the current status of electic scooters about two years ago, but such videos were and still are rather scarce. Thanks to folks like you this is greatly improving now :-)

Just wanted to let you know that I went to a scooter shop today with my front wheel to get it balanced and they told me it was very much out of balance, they had to add 45g to one side which is very much according to them.
I haven´t tried the scooter yet, propably tomorrow, will let you know how it works out.
It´s a shame this is not made in the factory, strangely enough the motor has some balancing weights on it. The scooter guys said that normally it´s the front wheel that really needs balancing, not the rear...

It appears the casting process of alumin(i)um rims is still more of a trial and error thing in China, as such massive amounts of balancing weights are fairly commonplace on Chinese scooters that were brought up to a really roadworthy state by their riders. The scary thing about this is that the region in which these weights had to be placed must be riddled with shrinkage cavities of enormous proportion. Remember that the rather low density of Al means that your front wheel could have shrinkage cavities with a total volume of around 16.7 ccm or even more !!!!
Of course the tires could also have some part in this, but I doubt it would be that much. I am thankful that my wheel and motor at least are very well balanced, and I think even without any weights. I can't check at the moment because my baby is still getting it's new front fork, something that we sadly waited too long for. The parts had been sitting in my dealer's workshop for several months already, but we had the wrong priorities, at least in part and in hindsight. First came the remedy to the miserable startup performance particularly with warm motor, second a luggage rack, and lastly a replacment BMS and winter tires. We probably should have changed the front fork first thing and saved us the hassle now and the scratches in the fairings...

Just wanted to let you know that I went to a scooter shop today with my front wheel to get it balanced and they told me it was very much out of balance, they had to add 45g to one side which is very much according to them.
I haven´t tried the scooter yet, propably tomorrow, will let you know how it works out.
It´s a shame this is not made in the factory, strangely enough the motor has some balancing weights on it. The scooter guys said that normally it´s the front wheel that really needs balancing, not the rear...

How to do front wheel balance? any kind of machine ? The rim is standard motorcycle rim and no reason unbalancing.

Rear wheel unbalancing is because of magnet,wiring and copper winding inside.

Any tyre shop should have a balancing machine. Should work for 13" wheels as well.
The problem, as I understand it, is that the casting process is not good, leading to imperfections within the aluminium alloy, and thus an unbalanced wheel.
I'll get my wheel to a tyre shop as soon as possible...

Of course you will need to have a fairly smooth road to feel the unbalance, otherwise you'll probably have to ride the exact same route with a balanced and unbalanced wheel to feel the difference.

/K

Mountain, driven at high speeds all wheels needs balancing, cars, motorcycles or scooters.
It´s a combination of unbalance in the rim and tire that needs to be taken care of.

Klas, haven´t tried the scooter yet, it´s very windy and rains today :-(
In my case you don´t need a smooth road to feel the imbalance, the front was vibrating quite severe at top speed, a combination of imbalanced wheel and soft fork I think, we´ll see..
Any tyre shop cannot balance motorcycle/scooter wheels, you need a special machine for theese.

The rim is standard motorcycle rim and no reason unbalancing.

Rear wheel unbalancing is because of magnet,wiring and copper winding inside.

Chen, recall that the valve stem alone yields an asymmetric tire. No measurements are ever perfect. That is why all things are built within specific tolerances. No wheel is a perfect circle. I am sure you know this, but I guess here we are talking about degree.

How to do front wheel balance? any kind of machine ? The rim is standard motorcycle rim and no reason unbalancing.

Rear wheel unbalancing is because of magnet,wiring and copper winding inside.

Check out this dynamic balancing machine for instance:
http://www.klsupply.com/WHEELEQUIPMENT/WHEELBALANCERS/MC2300DYNAMICWHEELBALANCER.aspx
Maybe a little overkill, as static balancing can be done manually with only a small kit of parts and a bit of patience, but for a batch production like yours a machine like this is probably the better option.

I still find the headlights on the scooter to be dangerously dim, even on high beam so I'm thinking of upgrading to HID bulbs. But I'm going to do it legally by installing the hid bulb in a projector. I will let you know how I go. I will only do one to start with to see how it goes.

When I get back home I'll post up some photos to show just how bad the lights are.

Have a look at this thread: http://visforvoltage.org/forum/5247-better-lighting-evd-amp-xm3500
Starting from post #47.

Well today we have really nice weather and I have tested the scooter and there is a really big difference after the front wheel was balanced.
Now there are no big vibrations and it´s totally much smoother to ride, I love it!

Haha, nice to hear Johnny! My bike is also back home with a new fork, it's shocks containing around 20ml more oil per side, and steering head play now reduced to the point of it just barely still being allowed to move freely. And I found my dealer had put on 25 grams of lead rather close to the valve on the front wheel, even before I first got my bike. It pays to have a dealer in between to solve most of the problems before I find out they existed at all :-)
I have so far not been able to replicate the heavy braking shudder, which is a very good thing, but I am not amused about the very poor traction of the very noisy IRC Urban Snow winter tires on dry roads: I can now easily make the front wheel lock up during emergency braking! I will have to train myself for the best emergency braking technique in order to find the best compromise of braking force and keeping the front wheel turning while the bike still moves...
The only good thing is that these tires do not completely loose grip even when skidding, but they squeek like mad.

EV enthusiasts
Has anyone given any thought to putting a second hub motor on the front.
2 x 4000w peak motors would have better cooling than a single rear motor and it gives a development path should I find a 4000w scooter lacking. Do not give consideration to battery or electrical or even Australian law. I am interested in the mechanicals of taking a rear wheel motor and bolting it to the front forks. You guys who have played with them may have an idea.

Besides I have always liked twins. Honda dream, Suzuki Titan, Ducati 860

Thanks in advance
Phill Hine Queensland Australia

Handling issues aside, the problem with these bikes isn't a lack of power in the motors - it's battery storage capacity. We could put in super heavy duty controllers and get the same result power-wise as adding a front motor, but would be out of juice in *either* case in about 10 miles. Your solution is more applicable to bicycles, where it's often impractical to have one giant hub motor putting out large amounts of power.

EV enthusiasts
Has anyone given any thought to putting a second hub motor on the front.
2 x 4000w peak motors would have better cooling than a single rear motor and it gives a development path should I find a 4000w scooter lacking. Do not give consideration to battery or electrical or even Australian law. I am interested in the mechanicals of taking a rear wheel motor and bolting it to the front forks. You guys who have played with them may have an idea.

Besides I have always liked twins. Honda dream, Suzuki Titan, Ducati 860

Thanks in advance
Phill Hine Queensland Australia

If you search the forum you will find other threads about 2 motors, please don´t start off-topics in this one, it´s long enough already :-)