Bought a new bike! (new member)- update

[andrey320]

I think I need to take that promo of the bike back....
My bike broke on the way home!
One of the pedals ate away the thread inside the crank and fell off. At least its a mechanical failure. The bike will not give me assist unless I am pedaling. I think it was designed this way. That is why I thought it was broken. The motor only runs when the pedals are above certain rpms or at a certain RPMs. So I had to "pretend" to pedal with one foot and push on the crank with the other. I pretty much "limped" home.
The batteries seem to work great though. 12 mile ride and lights show full power.
I registered the bike today and will call currietech tomorrow.
If I replace the cranks with slightly longer ones, will I get a little higher top pedaling speed?
I'll take pics and update tomorrow.
I'm bummed

 

[Reid Welch]

Andrey, it's a fairly common assembly defect, that the crank arms get switched left-for-right at the factory.

The pedals are left hand thread on the right side crank, and vice versa.
Is it possible your cranks were put on the wrong sides?
If so, the pedals will unscrew themselves in time, with the bummer results.

An easy fix, if that's all it is.


Longer cranks will give you more torque, but less top speed, I'd think
(in the sense that you'd be whipping your legs around in a greater circle).

--

What a nice bike though! The hubmotor is super high tech for this sort of thing;
it's got torque and efficiency for the -design center standard- of the bike
(I'm presuming).

I also presume that if we were to overvolt the motor to get greater speed,
this tiny, sealed-up unit may suffer from heat-related failure.
So, if it's used as intended, and not lugged up long hills
(you're not doing that), it's really about ideal.
A great value, that bike, at that price.



Prediction for Andrey
(ha ha)

Be not bummed;
that motor hummed.

The crank shall turn:
it's speed you'll yearn.

 

[lemmiwinks]

It sounded to me as though the crank had chewed out where it fits to the bottom bracket shaft Reid. Hopefully it gets fixed up quick whatever the case.

The biggest disadvantage of longer cranks as I understand it is increased pressure on the knees. Standard seems to be 170mm, bent riders seem to like 150mm or even 110mm in some cases. A shorter crank means you can pedal faster (higher cadence) but you'll want nice low gearing for hills. I'm a "spinner" http://www.sheldonbrown.com/gloss_sp-ss.html#spinner so this is my preferred method of cycling anyway. If you're a "masher" http://www.sheldonbrown.com/gloss_m.html#masher you might not like spinning (but it's better for ya)

 

[andrey320]

I think the problem is a cheap (soft) crank. The pedal chewed the threads out on the crank where it connects to it. So the pedal just fell out. Threads on the pedal look slightly mashed. The (female) threads on the crank are almost gone. Probably was not a mistake during assembly because the two sides are different.
You guys are right though, its not a big problem. Weak point that needs to be replaced. I just want to ride my bike!
I guess I'll stick with the standard or replacement cranks.

Reid Welch: Thanks for the diagram and this -

Be not bummed;
that motor hummed.

The crank shall turn:
it's speed you'll yearn.

Makes me feel better....

Here are the three things that I could read on the controller (the rest is in Chinese) - 300W, 24V, 15A. Is this a good controller for the size battery and motor?

The motor is stamped TONGXIN (you were right Geebee) and has a small green sticker that says, "Acebikes bicycles(taicang)co,ltd"

 

[xyster]

300W, 24V, 15A. Is this a good controller for the size battery and motor?

I think so in that it matches your motor's rated output closely, and your battery's ability to feed electricity. And the power output seems to meet your expectations (for now !!! )

Watts = Volts X Amps
so
360 Watts = 24 volts X 15 amps

I don't know why they labeled it 300 watts. Not a big diff anyway.

Voltage is like water pressure in a hose. Higher the voltage, higher the 'pressure' of the electricity pushing it through the wires and components. Amperage is like the diameter of a hose. Higher the amperage, the more electricity goes through the components. It takes volts to push amps. You won't find a 6 volt 100 amp controller.

Voltage is also proportional to motor RPM. So if you want to go faster (without pedaling harder) you must increase the voltage, which means more batteries.

Amperage is proportional to torque. So if you want to climb a steeper hill, or accelerate quicker, but not go faster, you can buy or modify a controller to provide higher amperage, while keeping the voltage the same, meaning you don't necessarily need more batteries, but your same batteries will drain faster.

Watts (volts X amps) is Power.

There's a little more to it...but that's the basics behind most of the electrical mods discussed here.

Hope you can get your pedal fixed pretty easily...

 

[andrey320]

Thanks for that quick ebike lesson xyster.
Called Currietech, told them the problem, cranks on order, will arrive next week. I will have to cover the install or do it myself. Easy and painless. Maybe I should take advantage of the warranty and order some parts I think may break in the future....
Here are some pics of the crank carnage, controller, and where the wires connect to the controller / battery. I think I may have to make some kind of cover for the controller or the wires. Its right on the bottom and is exposed to water.

 

[xyster]

Ah, there's the controller! That's a better place to put it than in the frame, so long as it's in a watertight case and doesn't hit when jumping curbs and stuff -- better airflow to help the controller cool.

 

[Mathurin]

I want to see the insides of the motor and controller!

Ok, we'll let you blow it up first before we take it apart. If it's well made, that won't happen for a while.

Let's see how much we can jack up the voltage!

 

[xyster]

Mathurin, you're going to scare off the new recruits...errrr, members... who'll rightly suspect endless sphere is some kind of cult. We don't let them know that until the first steps of indoctrination/assimiliation are complete!

 

[Geebee]

The main reason that cranks strip the thread is inadequate tightening of the pedal as they loosen they grind the thread away, the softer cranks are actually the better quality ones the cheapies are steel.
When the pedals are refitted torque them up pretty tight and make sure you put a smear of grease on the pedal threads or you will not be able to remove them in the future.

 

[fechter]

As I recall, the Tongxin motor uses a sensorless controller. See any hall wires? There was a guy from Tongxin on the old V forum who had the inside scoop. I think sensorless is the way of the future. Sure makes swapping motors and controllers easier.

 

[andrey320]

Geebee: I did nog know that. Never had that problem before. I'll tighten the new ones good.

Fechter: What does the sensor do? What are hall wires?

 

[lemmiwinks]

Thanks for that quick ebike lesson xyster.
Called Currietech, told them the problem, cranks on order, will arrive next week. I will have to cover the install or do it myself. Easy and painless.

Ah, I get it now, I was thinking the other end of the crank where it attaches to the bottom bracket shaft. Like Geebee says, the pedal was probably a bit loose, they will tend to unscrew themselves if not tightened enough.

You'll need a crank puller to get the crank arms off. Available from any bicycle shop.

 

[Reid Welch]

I'm a great fan of anerobic threadlockers.
I see benefit and no downside to use of blue (medium strength) locktite stuff on your new crank arm.

Why? The soft metal--if it's cleanly threaded, great! Then a dab of grease, like GeeBee advised, to prevent galvanic corrosion over the long haul time.

But if the threads of either the pedal or the crank are the least bit less than ideal? Lock 'em. This makes ALL the contact surface SOLID, and so prevents the tendency of the steel pedal pin to first wallow, then fall out of the soft aluminum crank.

Full contact of all threads with a hard, rather solid filler, is a good ticket here, imo. When it comes time to take it apart, a bit of torch heat will make it go easy.

Anyone disagree? I'm all for sharing opinions and experiences--which do vary from one person to another.

 

[TylerDurden]

I'll agree and add some items I keep handy...

 

[fechter]

Don't get those mixed up, especially the last two!

andrey320 wrote:

Fechter: What does the sensor do? What are hall wires?

Let me re-phrase the question:
How many wires are coming out of the motor? If you follow the wire back to the controller, there should be a connector of some sort. How many pins on the connector?

If it's hard to see, don't sweat it.

 

[andrey320]

Fechter: I'll take a look at the wires tonite

I recieved the crank arm set today. Because our work bike club does not have a crank extractor tool for me to borrow and the price of one is about $20, I will have a local shop do the work. They said its going to be $10. Looking forward to getting the bike rolling again and going on a long ride!
My parents house is about 12 miles away. It should make it 24 miles on a single charge, right?

 

[xyster]

My parents house is about 12 miles away. It should make it 24 miles on a single charge, right?

With a 9ah (amp-hours) battery pack, you're right near the edge of being able to make this comfortably. Whether you do or not will depend on amount of pedaling, hills (even though you get a free ride down, that never fully makes up for the extra energy needed to go up), wind, your speed (slower eats much less energy), etc.

Can you bring the charger and plug in there?
Even just charging for an hour could make the difference.

 

[jondoh]

With 9 ah, if you pedal a little and stay above 15mph, i'm thinking 18 miles will be your range. If you peddle a lot and/or stay around 12 mph, you'll make 24 miles. Either way, you'll want to bring the charger along.

Wait, your Nimh aren't really broken in yet since you just got them. you'll have to subtract 4 miles from my estimates above.

 

[Ypedal]

Have you tried taking the crank arm off yourself ?

If the bike is fairly new and you have not Mashed the pedals much.. it might just pop right off..

 

[andrey320]

I'll bring the charger along for the ride. I will be pedaling most of the time. Don't forget that I cannot get this bike to ride all on its own. I have to be pedaling to keep the motor running. I could just keep the pedals rotating without much effort, but I want to go a long way so I will be working.
Is it more efficient to "pulse" (accelerate then cruise, repeat...) or to "coast" at a set speed?

Ypedal: I have not tried to take it off. But I will tonite! Thanks for the suggestion.

 

[xyster]

Is it more efficient to "pulse" (accelerate then cruise, repeat...) or to "coast" at a set speed?

It's more efficient to keep the throtte set as close to as in one place as possible. Pulse/cruise/pulse/cruise uses more gas in cars, and more electricity on bikes for the same reasons that it's more efficient to ride at one single elevation than to ride up a hill and then coast back down -- acceleration takes much more power than maintaining speed.

 

[Mathurin]

Pulse/cruise/pulse/cruise uses more gas in cars[...]

Wrong you are Ken, it's a technique used in fuel economy competitions. It minimises throttling losses, the main source of loss in an otto cycle motor.

http://www.metrompg.com/posts/pulse-and-glide.htm

 

[Ypedal]

Xyster - Are you 100 % sure of this ?

Slowly giving throttle to prevent high-amp spikes.. and then coasing ( Specially with a system that freewheels... ) is efficient...

Even with my hub motor giving some drag.. i found that this process does extend range ( Using my DrainBrain of course )

 

[xyster]

Interesting, I'd like to learn more about this. I'm dubious. I'll start another thread.