Fork issues, motor recommendations, and other newbie questions/issues

[amberwolf]

Would a smaller wheel get me better acceleration?

Yes, but you can't use a smaller one on that bike, without changing the geometry, handling, steering, etc., and also taking away your rim brakes. (teh calipers won't reach anymore). Since you dont' have a disc option, it'd mean no front mechanical brake at all. Changing the fork to a disc capable one would fix that, but still leave you with the geometry change.

To see the difference in torque vs wheel size, use the simulator A vs B mode (compare), and set them both up exactly the same except make one with a smaller wheel.

Although I wouldn’t travel over 20 mph often I’d like to have the ability to push passed 20 would I be better off with a 750w motor?

750w is enough for up to 20-28mph, under ideal conditions.

If you really want the hard acceleration, you might want to stick with the higher power motors. Plus, it will give you the ability to overcome headwinds and maintain the same speed, or go uphills at the same speeds, etc.

Again, you can simulate these things on the ebikes.ca simulator, to see what different power levels get you, under different condtions. There's also a trip simulator.

but i did see a nice trek dual sport that I liked with a front suspension, but it’s made of aluminum so I don’t know if it would work.

The only thing I don't recommend is carbon frame/fork, but have no experience with them, only seen a lot of busted carbon pics online (like the site of that name). Aluminum, magnesium, steel, etc., all work fine as long as you use proper torque arms correctly mounted. I used 2kw DD hub 26" wheel on an aluminum suspension fork on CrazyBike2, and later moved that fork to the trike. Didnt' break it until I crashed and that only broke the crown--the rest of the fork is still fine (if unusable).

I also broke the dropouts off a different fork compeltely just testing a motor in it upside down and offground, because I forgot to put the nuts on it and didn't have any torque arms. And I spread dropouts on a steel fork with a few hundred watts, spinning out the axle, with just torque washers and no torque arm... So, if you don't secure them, you can break anything.

So what do you think I should shoot for In a set up if I want a good balance between taking off fast, 25 mph top speed, and good range, on either a hybrid like a surly, a hybrid with suspension like a trek dual sport

How quick an acceleration do you need? CrazyBike2, with about 4kw of power in 2WD hubmotors, did about 4 seconds to 20MPH, at something like 400lbs with me on it and some stuff. I'd have to use the simulator to see how much torque it actually had.

If you know the accleration time, and the mass, you can determine approximate torque needed to do that. THen you can look at the torque a motor is designed to do at a specific voltage and current, in what wheel size, and see if that meets your needs.

I wonder if 2 small geared hubs at the front and back would work well here?

Unless you need redundancy, it's mostly just more weight and complexity and cost. To see the difference, use the simulator to copmare a system with one bigger motor, with a system with two smaller motors (system A and B Add mode)

A beefy rear hub does sound fun, but what’s best in terms of accelerating, rear or mid drive?

Entirely depnds on the specific system, wheel size, gearing, etc.

But if you hve a shiftable-gear drivetrain on the middrive, then you can use less power to get the same torque or speed, by shifting down to low gear for accleration, then up to higher gears for speed. But there is still a certain amount of power needed to reach a certain speed, etc.

 

[Kemosabe70]

I will get back to you guys shortly after I find some time to do testing today (if I can find some) and disassembling. I’ll also snap some more photos.

Can someone recommend a good title, I always sucked at this in university. :lol:

 

[MadRhino]

I would not worry much about any bike going 18 mph. Almost any kit will do your ride requirement as well. If you need good brakes and plan to replace your fork, buy one that has IS brake mounts and spend as much for a big DH hydro disc brake as you did for the bike. This could be cheaper if you buy a used fork, used brake, and service them yourself. The rear brake is not important, and can be left as is. Motor regen is an interesting feature for some, but never to be considered as main brake. Braking from the rear is a bad habit that is stretching braking distance considerably. When an emergency will happen, this bad habit can kill you. One must be trained to stop the shortest distance that his equipment is capable of.

 

[Kemosabe70]

I think I see what you're talking about.

First, are both the motor axles fully seated in the dropout? If either one is slightly not, then it will make the fork look funny because the wheel is tilted. This would also explain braking problems, becuase the rim surfaces can't be flat to the pads if the wheel is at an angle.

At this point and at the time of originally posting this, it was seated properly. When installing the second torque arm from Grin i mistakely didnt fully seat the axel, but fixed this before heading out. BEFORE that though, lets say the first 15 miles, it could have very well been misaligned.

Does it look normal without the motor in it (with the regular wheel instead)? Did the motor have to be pushed into the dropouts. spreading the fork? If so, the motor is too wide for the dropouts, and the fork happens to be sligthly easier to bend on the fork leg that is sticking out more.

If it's the same either way, then it's just the fork itself, either designed that way or a flaw in manufacturing.


Now, on the gap between axle flats and dropout sides: That shouldn't be possible, unless the dropouts are spread out. Was this gap present originally? If not, it means the axle is rocking in the dropouts and is not mounted correctly, that the torque arms are not mounted right or not tight enough (meaning, the hole in the arm is too large so teh axle can move in it, instead of being a tight fit).

If the gap was there originally, then either the motor axle is way skinnier than I've ever seen (10mm between flats is normal), or the dropouts were already bent/ spread, or were cut or ground out for some reason. (regular wheel axles are 9 or 10mm).

As of now, the fork does not spread when reinstalling the front motor wheel, but thats not to say it hasn't stretched already. I had some interesting findings when installing the original wheel. (see photos)
1. The drop outs are bent and the drop out that originally did not have the torque arm is about 1/8th of an inch wider
2. The fork seems to be bent to the drivetrain side of the bike
3. as you can see from the photos when putting on the original rim the brakes that have been centered for the motor wheel is significantly off centered from its original position

I wonder what could have caused this, I am thinking that it could be a few things
1. poorly installed original torque arm
2. original torque arm wasn't strong enough
3. the motor axels were never seated correctly

Question: without swapping out my fork and having installed the Grin v2 torque arm securely would this bike still be safe to for testing? (I am still trying to figure out a good acceleration time I would like to shoot for)

Since your fork ins't suspension, then it cant be bushings causing the flex, so it's still possibly a loose headset. The fork may have some forward/backward flex in it, that's normal and desirable for nonsuspension forks like that (helps with some bumps, etc).

not 100% sure if my headset is loose, but it feels pretty snug?

How quick an acceleration do you need? CrazyBike2, with about 4kw of power in 2WD hubmotors, did about 4 seconds to 20MPH, at something like 400lbs with me on it and some stuff. I'd have to use the simulator to see how much torque it actually had.

If you know the accleration time, and the mass, you can determine approximate torque needed to do that. THen you can look at the torque a motor is designed to do at a specific voltage and current, in what wheel size, and see if that meets your needs.

This week is super busy for me at work and I haven't been able to test as much as I'd like to but I was able to do 5 runs from 0-20 mph on a smooth flat road. I used "GPS race timer" from the app store on iPhone and here are the results from 0 with no pedaling level 5 (max) 100% throttle:
1. 11.6s 200ft.
2. 10.3s 223ft.
3. 10.9s 243ft.
4. 10.9s 217ft

and the last run i started with about 3 revolutions on the pedals
5. 7s 167ft.

I wish I had more time to test, but I did find this very interesting. An issue I ran into with the Ebikeling kit is that the PAS sensor wont fit on my BB so I have been riding and testing throttle only. I feel as though I cant accurately gauge how powerful of a motor I would need for the acceleration I would want because once I do install a PAS sensor, which is must for the future of this build, I will most likely be using it with the PAS more often than not.



THE NEXT STEP:

The Wyatt Street King has always been dear to my heart, but ultimately never fit me right (too big) and with the fork needing replacing presumably, I have decided I will replacing it with a new donor. With the added weight of a beefy pack and being that I am a heavier guy I think i may appreciate a bike with a front suspension or maybe a fat bike. Leaning towards a hardtail, I really like the look of a battery mounted underneath the down-tube (although not necessary) and curb hopping...so I want something tough as nails that I can not worry about beating up in terms of hard urban riding (feels weird typing this, but its the easiest way to describe it!...not sure if it's the right move, and this is just my initial thought, but I find think they’re both really cool looking bikes and aesthetics are a big deal to me.

Questions regarding choosing a donor:
1. Being that i am going to be riding around the city, I would be better off with a hardtail over a full suspension bike, right?
2. With all the added weight of the kit onto the bike would i be able to fit a rear rack onto a hardtail?
3. I wouldn't be loading it up too often and like i said it would be for some groceries, but I would want at least a rear rack installed for when i do need to carry something, would i be better off with a rigid frame?
4. I really like the idea of having a single speed bike because of the low maintenance, does a rear hub add more wear to my drivetrain as a mid-drive would, especially on a single speed?
5. I wonder if i could take a stock wheel included with a new bike and relace that one with a hub motor..would look super clean!
6. Does using a carbon belt drive limit my options in terms of motors? (mid drive/front-hub/rear-hub)
7. I am really lost in terms of motor options, but I guess that will become easier to figure out once I have decided on the donor?

IDEAS:

1. I have that extra battery laying around, if that could be salvaged, I could use it as a range extender and put it on the rear rack for longer trips, not looking for more power, just more range. I want this to be an optional plug and play option and i wouldn't mind having to mount a rack on the rear rack for this on the occasional longer ride.
a. Is this possible?
b. can both batteries power the same motor?
c. If possible, how hard is putting together a set up like?

GRIN SIMULATOR HELP:

A few questions here
1. Does the controller make a huge difference in range and power so long as the amp rating is higher than the max output of my system?
2. Whats the difference between phaserunner hot and phaserunner cold?
3. In terms of throttle % is there a standard amount I should be using, should I compare all motors with 100% throttle, auto throttle, etc.?
4. There are SO many motor options, it is really intimidating, I know this request gets thrown around a lot, but any suggestions would be greatly appreciated.
a. I will (probably) be using either a fat bike or more likely a hardtail mountain bike for this build, I would like decent acceleration off of the line, but I wouldn't mind having to pedal a bit to achieve that.
b. More often than not I will be using this bike on busy NYC streets with lots of stop and go, is there a certain motor that works best for this? I have read that geared motors would be best, but I am also curious how that would compare to a direct drive motor if I were to pedal start from 0 rather than not in terms of getting the most range.
c. This motor will not be installed on the front end, it will be either rear drive or mid-drive
d. 20 mph feels fast for me, so there is technically no need to have the ability to go above that, but would be nice to have power to tap into like I have mentioned previously


p.s.
Although I have pretty much scrapped the Street King at this point, I feel like we should continue to trouble shoot the fork issues in order to better serve the community and future new builders. I am more than happy to further discuss what went wrong with the fork here!

 

[Kemosabe70]

Some more photos of the motor wheel.

Those washers with the tab (not sure what they’re called) that are supposed sit in the eyelet are nowhere near snug. I wonder if that could have also been an issue.

Please note, those bolts are not tightened.

 

[goatman]

a picture is worth a 1000 words so I took a picture of your picture and I used a pen as a pointer.

see where the pen is pointing? I don't think the fork drop-out is supposed to sit there

I think its supposed to sit here where your torque washer is

it looks to me like when you tightened the axle nut, the drop out flared. see where the pointer tip is, that's a black chamfered edge, as you tightened the nut the drop out flared open?

but I don't know

 

[Kemosabe70]

In the middle of making dinner, but here are some more pics with it tightened onto the fork.

 

[Kemosabe70]

a picture is worth a 1000 words so I took a picture of your picture and I used a pen as a pointer.

see where the pen is pointing? I don't think the fork drop-out is supposed to sit there

I think its supposed to sit here where your torque washer is

it looks to me like when you tightened the axle nut, the drop out flared. see where the pointer tip is, that's a black chamfered edge, as you tightened the nut the drop out flared open?

but I don't know

When I originally tightened that side, a few things could have been wrong I guess. Maybe the axel wasn’t seated into the drop out on one side or I could have had the washer in the wrong place, or could it be that I poorly installed the torque arm or maybe that the torque arm itself just sucks. Maybe I need some sort of spacer? As you can see when I install the original rim, the brakes are off center, but sit center on my motor even at this point, that’s weird too.

I don’t know either.

 

[99t4]

Last 3 photos show the RH side dropout is bent. Unless I'm seeing a photographically-induced illusory artifact.

You will want to repair that. If you don't know how or don't have the tools your FLBS should be able to do it for you in minutes.

 

[Kemosabe70]

Last 3 photos show the RH side dropout is bent. Unless I'm seeing a photographically-induced illusory artifact.

You will want to repair that. If you don't know how or don't have the tools your FLBS should be able to do it for you in minutes.

Do you have any idea how this could have happened?

 

[mark5]

Keemosabe, what you don't want is for your dropout to get flared like the one in the foreground of this picture:
https://endless-sphere.com/forums/viewtopic.php?t=12475#p185732

Like goatman points out, there's already a gap there. You did write that you ran it without torque arms before.

It would be good if you could pull your hub motor and take closeup pictures of your dropouts.

 

[Kemosabe70]

Keemosabe, what you don't want is for your dropout to get flared like the one in the foreground of this picture:
https://endless-sphere.com/forums/viewtopic.php?t=12475#p185732

Like goatman points out, there's already a gap there. You did write that you ran it without torque arms before.

It would be good if you could pull your hub motor and take closeup pictures of your dropouts.

Are these 2 not good enough?

 

[Kemosabe70]

Keemosabe, what you don't want is for your dropout to get flared like the one in the foreground of this picture:
https://endless-sphere.com/forums/viewtopic.php?t=12475#p185732

Like goatman points out, there's already a gap there. You did write that you ran it without torque arms before.

It would be good if you could pull your hub motor and take closeup pictures of your dropouts.

Also, to be clear I never rode without a torque arm, but that side that you are referring to originally did not have a torque arm.

 

[mark5]

I must've glossed over those 2 pictures.

Because of the picture angle it's hard to see whether the flat's sides are square with each other and whether they'd fit snug, no gap, with the flats of the axle. First picture looks like the dropout might've opened up some.

Maybe also closeup pictures of the motor axle fitted into the dropouts but without washers, torque arm, nut, etc. to see how well the axle fits.

 

[Kemosabe70]

I must've glossed over those 2 pictures.

Because of the picture angle it's hard to see whether the flat's sides are square with each other and whether they'd fit snug, no gap, with the flats of the axle. First picture looks like the dropout might've opened up some.

Maybe also closeup pictures of the motor axle fitted into the dropouts but without washers, torque arm, nut, etc. to see how well the axle fits.

Okay, I will work on this for tomorrow, and post some pictures. Pretty sure it’s been flared out about 1/8th of an inch.

 

[goatman]

you see this torque washer, flip it around so its on the inside between motor and drop out, youll have to spread/ force the fork on but then the axle should sit down in the drop out.

your motor axle looks too wide for the fork

 

[Kemosabe70]

you see this torque washer, flip it around so its on the inside between motor and drop out, youll have to spread/ force the fork on but then the axle should sit down in the drop out.

your motor axle looks too wide for the fork

I can for sure do that, but I’m pretty sure in its current state the motor axel is fully seated into the drop out already.

Any recommendations on motors on should be testing on the simulator? Lol

 

[goatman]

the motor, I still think your battery cant handle more than 30 amps max, id be looking for a geared motor but if your going fat tire you need a fat tire geared motor?????
instead of fat tire you can run plus size like a 2.50 to 3.0 hard tail with a skinny tire on the front shock, trying to push a 3.0 or fat tire upfront will kill your range.

hot/cold phaserunner, I don't know, I think if you hit thermal rollback you lose some amps unless you heatsink it, I pull 56amps/3200 watts through it no problem but my battery is only good for 40 amps. so if your at 30 amps you shouldn't have to worry about it

you have a back up battery, I plug my back up into the charge port of my main battery but i parallel all the time also. I shared a bit in this thread of the Marin build
https://endless-sphere.com/forums/viewtopic.php?f=6&t=104027#p1527424

if you can find a giant stiletto that's a nice bike to build on. your 5'9 and 205 right?

 

[Kemosabe70]

the motor, I still think your battery cant handle more than 30 amps max, id be looking for a geared motor but if your going fat tire you need a fat tire geared motor?????
instead of fat tire you can run plus size like a 2.50 to 3.0 hard tail with a skinny tire on the front shock, trying to push a 3.0 or fat tire upfront will kill your range.

So I’ll go ahead and assume that a hardtail with regular tires would be more efficient than one with plus? If that’s the case, I’ll just go with a regular hardtail.
I’m thinking geared too because of all the stop and go in NYC, but to mid-drive or not to mid-drive? I’m not opposed to taking this thing out on a trail every now and again. I also don’t like the idea of having 2 different rims. Putting a mid drive on would obviously fix that, but I wonder if I could re-lace the original wheel on whatever donor I end of getting.

hot/cold phaserunner, I don't know, I think if you hit thermal rollback you lose some amps unless you heatsink it, I pull 56amps/3200 watts through it no problem but my battery is only good for 40 amps. so if your at 30 amps you shouldn't have to worry about it

you have a back up battery, I plug my back up into the charge port of my main battery but i parallel all the time also. I shared a bit in this thread of the Marin build
https://endless-sphere.com/forums/viewtopic.php?f=6&t=104027#p1527424

if you can find a giant stiletto that's a nice bike to build on. your 5'9 and 205 right?

5’10” 210*
Is that a chopper bike???

I’ll check out the thread now!

 

[amberwolf]

The two things that generally cause the dropouts to spread are:

--axle twisting in them from motor torque / braking, which acts as a lever and pries them open.

This can be exacerbated by so-called torque-washers, which are a bigger lever on hte axle to pry even harder at the tips of the dropouts, especially on this particular style of dropout.


--axle shape vs dropout shape allowing the axle to act as a "hammer" (wedge, really) to push upward into the dropouts, prying them open. The axle is a larger diameter than the dropout was designed for, so the curve at the top is flatter. So the top of the axle doesn't seat at the top of the dropout like a bike wheel axle would, and so the forces upward from the wheel thru the axle into the dropout don't go straight up into the fork. Instead, they are applied to the front and rear edges of the dropout at the ends of the curved portion, by the point-edges of the motor axle where the flats meet the top curved threaded section.




Even with torque arms these things can happen, if the torque arm is not a *perfect* fit on the axle. If it can be rocked on the axle even a tiny bit, it does not keep the axle from moving, and over time can even damage the ttorque arm making it even looser, etc.

Or if the torque arms are not mounted in a way that allows the axle to move either up or down or rotationally.

 

[Kemosabe70]

Should I make a new build thread being that this build is sort of done and I’m moving onto a new donar? Or continue the build thread here?

 

[goatman]

the motor, I still think your battery cant handle more than 30 amps max, id be looking for a geared motor but if your going fat tire you need a fat tire geared motor?????
instead of fat tire you can run plus size like a 2.50 to 3.0 hard tail with a skinny tire on the front shock, trying to push a 3.0 or fat tire upfront will kill your range.

So I’ll go ahead and assume that a hardtail with regular tires would be more efficient than one with plus? If that’s the case, I’ll just go with a regular hardtail.
I’m thinking geared too because of all the stop and go in NYC, but to mid-drive or not to mid-drive? I’m not opposed to taking this thing out on a trail every now and again. I also don’t like the idea of having 2 different rims. Putting a mid drive on would obviously fix that, but I wonder if I could re-lace the original wheel on whatever donor I end of getting.

hot/cold phaserunner, I don't know, I think if you hit thermal rollback you lose some amps unless you heatsink it, I pull 56amps/3200 watts through it no problem but my battery is only good for 40 amps. so if your at 30 amps you shouldn't have to worry about it

you have a back up battery, I plug my back up into the charge port of my main battery but i parallel all the time also. I shared a bit in this thread of the Marin build
https://endless-sphere.com/forums/viewtopic.php?f=6&t=104027#p1527424

if you can find a giant stiletto that's a nice bike to build on. your 5'9 and 205 right?

5’10” 210*
Is that a chopper bike???

I’ll check out the thread now!

yes but I forgot you wanted a rear rack, where I have the tank bag I used to have a hailong battery but youre wolf would fit there. then it looks like a gas tank, you sit low feet forward 3.0 tires with slicks is nice in the city. they don't make them anymore but youre in New York, might be one kicking around.
https://endless-sphere.com/forums/viewtopic.php?f=6&t=103833

 

[Kemosabe70]

the motor, I still think your battery cant handle more than 30 amps max, id be looking for a geared motor but if your going fat tire you need a fat tire geared motor?????
instead of fat tire you can run plus size like a 2.50 to 3.0 hard tail with a skinny tire on the front shock, trying to push a 3.0 or fat tire upfront will kill your range.

So I’ll go ahead and assume that a hardtail with regular tires would be more efficient than one with plus? If that’s the case, I’ll just go with a regular hardtail.
I’m thinking geared too because of all the stop and go in NYC, but to mid-drive or not to mid-drive? I’m not opposed to taking this thing out on a trail every now and again. I also don’t like the idea of having 2 different rims. Putting a mid drive on would obviously fix that, but I wonder if I could re-lace the original wheel on whatever donor I end of getting.

hot/cold phaserunner, I don't know, I think if you hit thermal rollback you lose some amps unless you heatsink it, I pull 56amps/3200 watts through it no problem but my battery is only good for 40 amps. so if your at 30 amps you shouldn't have to worry about it

you have a back up battery, I plug my back up into the charge port of my main battery but i parallel all the time also. I shared a bit in this thread of the Marin build
https://endless-sphere.com/forums/viewtopic.php?f=6&t=104027#p1527424

if you can find a giant stiletto that's a nice bike to build on. your 5'9 and 205 right?

5’10” 210*
Is that a chopper bike???

I’ll check out the thread now!

yes but I forgot you wanted a rear rack, where I have the tank bag I used to have a hailong battery but youre wolf would fit there. then it looks like a gas tank, you sit low feet forward 3.0 tires with slicks is nice in the city. they don't make them anymore but youre in New York, might be one kicking around.
https://endless-sphere.com/forums/viewtopic.php?f=6&t=103833

Okay I see what you mean now

It may not be practical but its such a dope frame to build off of

I can picture it now a weekend cruiser with some comfy tires and some sort of lock box for the battery

There’s so much space to build on it has the potential to be super clean

Still need to fix that battery though....
I would love to have that optional extended range

Before getting my Luna pack, I bought a “New(other)” hailong battery pack, it was 48v 14.5ah Sanyo cells that was marked as open box, the battery worked well for a a couple miles and then would sag down to its low voltage cut off.

Can’t I just replace the BMS if that’s the issue?

 

[amberwolf]

I also don’t like the idea of having 2 different rims. Putting a mid drive on would obviously fix that, but I wonder if I could re-lace the original wheel on whatever donor I end of getting.

Sure. You can probably take the two wheels to the LBS and have them move the motor from the wheel it comes in (or buy a bare motor) to the original bike rim; they should be able to cut new spokes of the right length, and figure all that out for you.

Alternately, it's not difficult to learn wheelbuilding, just time consuming. If you want to do that,first go to places like sheldon brown's bike maintenance site, and then get some old wheels that fit your bike (the LBS may have some), then take pictures of them so you can see exactly how they were originally built, and take one apart and relace it with it's own parts in the same way it was originally built. Then test ride it to see if your lacing holds up, and if it still fits on the bike. (don't use your original wheels to do this ).

Probably it's a balance problem. If leaving the pack ont eh charger constantly whenever you can monitor it, for as long as possible, changes the problem, making it work better for longer, then that's the problem. The actual cause of the problem could be several things, but none of htem are permanently fixed by the long charging (though you can just always leave it on the charger whenever you aren't using it, and it would help).

Can’t I just replace the BMS if that’s the issue?

Which issue? Balance problems are not usually caused by the BMS itself (though they can be). You have to test the pack to find out the source of the problem before you can fix it. The first thing is to find out the cell voltages to see if any really *are* at LVC, shutting off the BMS, and if they are all the same, or if they are significantly different from each other.

If they're all the same (when the pack shuts off during a ride), then the pack is probably just not able to deliver the capacity it's "rated" for. That could be the cells just being old and worn out (though they rarely age identically), or the rating could be an outright lie, or the pack may not even be the one actually advertised (not super common, but happens; seller copies someone else's page, then sends a product very different from waht's being advertised; BMSbattery is well known for this, though most people get what they ordered, not everyone does). Or the cells could be counterfeit--wrapped and marked as one cell, when they're really something much cheaper. The battery maker may not even know this...but they probably do.


But balance issues are a lot more common, and can even be a direct result of any of the above.


There's a bunch of threads that talk aobut how to test the cause of balancing problems, but here's some:
https://endless-sphere.com/forums/viewtopic.php?f=2&t=106794&p=1563915&hilit=balance+bms+charger#p1563915
https://endless-sphere.com/forums/viewtopic.php?f=2&t=106631&p=1562940&hilit=balance+bms+charger#p1562940

other stuff in this search, not everything is relevant:
https://endless-sphere.com/forums/search.php?st=0&sk=t&sd=d&sr=posts&author_id=13812

 

[Kemosabe70]

I also don’t like the idea of having 2 different rims. Putting a mid drive on would obviously fix that, but I wonder if I could re-lace the original wheel on whatever donor I end of getting.

Sure. You can probably take the two wheels to the LBS and have them move the motor from the wheel it comes in (or buy a bare motor) to the original bike rim; they should be able to cut new spokes of the right length, and figure all that out for you.

Alternately, it's not difficult to learn wheelbuilding, just time consuming. If you want to do that,first go to places like sheldon brown's bike maintenance site, and then get some old wheels that fit your bike (the LBS may have some), then take pictures of them so you can see exactly how they were originally built, and take one apart and relace it with it's own parts in the same way it was originally built. Then test ride it to see if your lacing holds up, and if it still fits on the bike. (don't use your original wheels to do this ).

Probably it's a balance problem. If leaving the pack ont eh charger constantly whenever you can monitor it, for as long as possible, changes the problem, making it work better for longer, then that's the problem. The actual cause of the problem could be several things, but none of htem are permanently fixed by the long charging (though you can just always leave it on the charger whenever you aren't using it, and it would help).

Can’t I just replace the BMS if that’s the issue?

Which issue? Balance problems are not usually caused by the BMS itself (though they can be). You have to test the pack to find out the source of the problem before you can fix it. The first thing is to find out the cell voltages to see if any really *are* at LVC, shutting off the BMS, and if they are all the same, or if they are significantly different from each other.

If they're all the same (when the pack shuts off during a ride), then the pack is probably just not able to deliver the capacity it's "rated" for. That could be the cells just being old and worn out (though they rarely age identically), or the rating could be an outright lie, or the pack may not even be the one actually advertised (not super common, but happens; seller copies someone else's page, then sends a product very different from waht's being advertised; BMSbattery is well known for this, though most people get what they ordered, not everyone does). Or the cells could be counterfeit--wrapped and marked as one cell, when they're really something much cheaper. The battery maker may not even know this...but they probably do.


But balance issues are a lot more common, and can even be a direct result of any of the above.


There's a bunch of threads that talk aobut how to test the cause of balancing problems, but here's some:
https://endless-sphere.com/forums/viewtopic.php?f=2&t=106794&p=1563915&hilit=balance+bms+charger#p1563915
https://endless-sphere.com/forums/viewtopic.php?f=2&t=106631&p=1562940&hilit=balance+bms+charger#p1562940

other stuff in this search, not everything is relevant:
https://endless-sphere.com/forums/search.php?st=0&sk=t&sd=d&sr=posts&author_id=13812

I would love to learn wheel building, but I work long hours (50+hrs ) and as of now I wouldn't be able to devote the time and effort to it.
I am going to try to sneak out today and grab a multimeter from the home depot down the block :lol: and then hopefully be able to devote some time this evening to looking into how to figure out the potential causes of the problem.