Another "stealth bomber" build.

[Merlin]

i would go sm pro...lacing job is easy. if you cant true the wheel, any mx shop can do it for you.

16 inch is pretty small for a 1cross pattern. its not worth in my opinion. 17" fits easy but tires are rare. best size is 18"
longer spokes also helps to flex more.

this rim you had was 10$ china shit. first LMX had also that crap. you could even put marks IN the rim with plastic levers.
anyway. i had excel and sm pro and bare rim is only 90€ in germany for a sm pro rim. a set of spokes is around 75€ for quality nipples and spokes.

before you bend and sm pro rim you will break your back. (thats not a joke)

if need help send me a message.

 

[j bjork]

Thanks, I have looked at the sm pro wheels. The prize is a lot better. Do you get custom angles, or just use the standard they come with?

Where do you get a set of custom spokes for 75 euro? That is a lot better then what I found.

I want a smaller wheel to get the rpm up, so I would prefer not to go bigger instead. I have 17" now.

The rim was surprisingly hard when I tried to straiting it out a bit. I was not able to do much with a hammer. It seemed to go alright in a press, but then it cracked

 

[Merlin]

if aluminium is bend, its over. you can only bend it once

for example sm pro 17x1,85 has a perfect angle for the qs205. spokes are straight in the rim. nipples dont touch the holes.

the difference between 16" and 17" is not worth in my opinion. before you order. post here a pic with a 16" moto rim and a 1cross laced 205 hub motor.
then we can talk =)

 

[j bjork]

Well, one reason to go 16" is the tire. A mx tire for 16" is 90/100 (90mm wide and 100% profile height) In reality the one I measured was 111mm wide with studs.
This is already too wide for the swing arm. For 17" the tire are 100/100, so it will be higher and wider.

I am a bit worried in that either tire will be heavy and draw a lot of power to turn, with their big studs.
Now I am using a front tire, 70/100-17. It does not have the same protection for the rim as the rear tires, and it wears out a lot. Maybe I can find another that will last longer though.

But if I do as I planned and go for a mx tear tire, I think 16" is better. But if that doesnt work out, I dont think I have the option to use a front tire instead..

I havent seen any pictures of a hub cross laced in a 16" wheel, but I don´t know where to look.

 

[j bjork]

The difference between a 90/100-16" rear tire and my 70/100-17" front tire I have been using for a rear tire:

And how much rubber it is that protects the rim:

Compared to my front tire that is 70/100-19", with the same side protection as the 70/100-17"

 

[Merlin]

I havent seen any pictures of a hub cross laced in a 16" wheel, but I don´t know where to look.

thats the problem. all ppl you ask for it will do it radial. without cross pattern.
16" moto rim with a 205 hub is "too small".
its possible but you have to bend spokes abit + nipples hit the rim.
the angle is pretty hard for the rim.

it looks like that:

if you put a 17x3.0 its pretty enough for whatever you do. the rim will not bend. no way. remember that this rims are used on mx bikes.
double the weight and 80-100 feet jumps. even when a jump goes wrong and you crash the rim will be ok.

buddy of me is an fmx freak. this year he crashed completly flat because he missed the landing. he landed on street coming from 12m height. (12!)

rims are ok. (bones not)

you see my avatar? its 18x3.5 and i made some decent jumps on street(flat) 1-1.2m height.
supsnesion buttoms out, rims are ok.

still up to you buddy. sharing just some years of experience. started with 19"....switched to 17" because wanted more efficiency and power.(wasnt worth either) and pretty happy now with 18x3.5 mx tire.

 

[j bjork]

Yes, I am grateful for your input. I have limited experience with 2-wheelers. It would be interesting if more people with experience would share their thoughts.

If I go with the custom drilled rim I guess they take the spoke angles in consideration, that would be the whole purpose. But it is just what the company suggested. Maybe excel will say it cant be done, or that it is unsuitable with a cross pattern.

I cant see the picture unfortunately.

The 16" will be a little bigger in diameter than the 17" I had, if I go 17" or even 18" and mx rear tire it will be bigger still.
As it was, the controller overheated easily, that will probably change when I get the nucular 24fet. But the motor is not far behind in heat, so that will probably be the next problem.. I already have statoraid, I can go with hubsinks too. But I don´t think they will do very much difference, because the outer shell on the motor is seldom much over 50c.

I asked about a 1,6x17" excel rim, but it was more expensive than the 1,85x16", at least from the swedish company.

I mean, bigger wheel diameter is not such a big deal for you. You have a middrive and can change gearing. It will still be heavier and more rubbing(?), but at least you don´t have to get lower motor rpm.

Another option is an sm pro 1,85x16" that they have on sale in the swedish company. It will not be custom angles, but the prize is right. Then I could test both cross and radial lacing with the spokes I have. They will be too long, but I would probably be able to see what could work.

My damage is not from jumps, it is from rocks on the trails I´m riding. I think part of the problem is the unsprung weight, about 14kg motor in the wheel..
That makes the rim take a lot more impact. I have not a single bump in the front wheel.. But sure, it is a low quality rim. A better quality rim would do a whole lot better. But I think it is a good idea to have more tire between the rim and rocks too.. Hard decisions :?

 

[Merlin]

The 16" will be a little bigger in diameter than the 17" I had, if I go 17" or even 18" and mx rear tire it will be bigger still.
As it was, the controller overheated easily, that will probably change when I get the nucular 24fet. But the motor is not far behind in heat, so that will probably be the next problem.. I already have statoraid, I can go with hubsinks too. But I don´t think they will do very much difference, because the outer shell on the motor is seldom much over 50c.

common mistake of hub users: between stator and shell is an air-gap. and this is the problem. you touch outside and think ok, i can touch it for some seconds. should be ok. and thats not. if you ride slow steep hills you can have 3 times higher temps INSIDE. (Outside shell 60...inside allready 180°) -install temp sensor- (!)
Ferrofluid evaporates over time. But FF closes the gap between stator and shell. Hubsinks do a pretty good job if FF is used.
at this point i didnt overheatet even on hills. controller stopped working 2 or 3 times but motor wasnt hitting 100°


I asked about a 1,6x17" excel rim, but it was more expensive than the 1,85x16", at least from the swedish company.

I mean, bigger wheel diameter is not such a big deal for you. You have a middrive and can change gearing. It will still be heavier and more rubbing(?), but at least you don´t have to get lower motor rpm.
I didnt talked about powerwise. i mean rim/tire combination and enough "rubber" on your rim with 18x3.5. Powerwise the hub sucks anyway from zero starting.

Another option is an sm pro 1,85x16" that they have on sale in the swedish company. It will not be custom angles, but the prize is right. Then I could test both cross and radial lacing with the spokes I have. They will be too long, but I would probably be able to see what could work.
custom angles you probably not need because 16" should be allready have slightly lower angle then 17" on same hub. But exactly this will "maybe" prevent the option for radial lacing. simply because the spoke angle(hole) pointed too much to the sides that you cant fit a nipple well on radial lacing. This will nobody know except of someone who WANT IT DEAD SERIOUS IN 16" :lol:

My damage is not from jumps, it is from rocks on the trails I´m riding. I think part of the problem is the unsprung weight, about 14kg motor in the wheel..

you are not the first using 205 hub on an ebike.
bumping some rocks will not bend a sm pro or excel. NEVER. not even with a flat tire.

That makes the rim take a lot more impact. I have not a single bump in the front wheel.. But sure, it is a low quality rim. A better quality rim would do a whole lot better. But I think it is a good idea to have more tire between the rim and rocks too.. Hard decisions :?

theres no need for a 4" tire on your hub bike. not to save the rim adding some Kilos of rubber.
If you want grip or a plushy ride ...how about tubliss? no problems with flats (i know what pita it is to change tires on a rear hub)
you can run 6psi or even run flat.

[youtube]SUpqm8O6kOc[/youtube]

 

[j bjork]

About motor temp, that is exactly what I mean.
Even with statoraid the outer shell is seldom much over 50c after a ride.
But the windings are usually 100-120c

That is why I think hubsinks probably wont do very much difference.
But I already have a set, so I will probably mount them.
If they keep the outer shell 10-15c colder, it should still help some with the cooling of the windings by keeping the statoraid a little colder.

I looked around a little more, in the mx stores here they only have 90/100-16", 100 and wider rear tires for 17"-
But I found 3.00-16", 3.50-16", 3.00-17" at a tire store. I don´t think I will have to go wider for grip, that was ok with the tire I had. I don´t ride in mud and dirt, so far I have´nt at least :wink:

https://endless-sphere.com/forums/viewtopic.php?f=2&t=64324&start=200

1/3 down this page is a cross laced 16" on a hub

I will try a little more to find a 1.6-17" rim, than I could use tires I have, and hopefully the spokes too.
Otherwise I think I will buy the sm pro 1,8-16" I found at a good prize.

 

[Merlin]

Great.
Watch on this Pic how the spokes come out of the nipples.
They all bend.

Can work on street without problems.

A well build wheel doesn't need 8g spokes. Even 12g would be enough for a 10kw hub. More flex, way better wheel.

But mostly not so well build wheels will be compensate with 10g or even thicker spokes.

Anyway. Reminding to this Pic I wouldn't go for 16"


Put the hubsinks on... When you Allready have them..
Why don't you installed?

 

[j bjork]

Damn, I didn´t enhance the picture. You are right, they all are bent.
I have already ordered the rim and a tire now, so I will have to make it work..
I hope to be able to file the holes a little if necessary to get straight spokes.

I haven´t had a need for the hubsinks yet, the controller overheats before the motor.
But I hope that will change with the nucular 24fet.
I realized some time ago that I would have to do something about the wheel, so I waited with the hubsinks.
I thought it is better to install them when I have a wheel that lasts.

 

[Merlin]

17" is allready tight fitfor hubsinks.....maybe 16" you cant install them

 

[j bjork]

Maby I wont need spokes, I can just weld the rim to the hubsinks :wink:

 

[j bjork]

I got the new rim today.
I wanted to see how the spoke angles would work out, so I put in my old spokes:

It looks like it can work, but it is difficult to say.
The spokes are too long, so I don´t get the nipples in the holes.

I did some calculations, and it seems like spokes on the inside should be 94,5mm and spokes on the outside 96mm (95,9)

https://www.ebikes.ca/tools/spoke-calc.html?hub=cust_d232_s43_o0_n36_l156_h4_p40.5&pair=false&rim=cust_dia406_e390_lo0_ro0_w24&lelb=in&relb=out

It sounds about right, the spokes for the 17" rim was 108mm. I ordered a set of 96mm and hope that will work..

 

[j bjork]

I got the tire and tube some time ago.
I was a little surprised by the big box, I just ordered a tire and a tube?

Yes there was just a tube in the box..

Eventually I got the spokes too, and was able to test lace the wheel.

That was the first try, the spoke angles was not very good.
They were also too long.

I had to modify the rim a little to get better spoke angles, and cut the spokes a little.
I also cut a little more threads on the spokes just in case, it was not really needed. But the nipples were rather close to bottom out in the treads.

This is how it looks when finished, it is not perfect but I think it will be alright.

I used shims like this when I mounted the wheel:

The dropouts is far from perfect, a good clamping system would be better. But this will have to do for now.
I was able to fit 4 strips on one side (a total of 0,8mm) and 3 and the forth half way on the other side.
It feels solid when i torque down the clamping bolts before the nuts on the axle, but time will tell..

 

[j bjork]

I like the width of the tire, but it is more like a moped tire with coarser pattern. It doesn't have the side protection of a real dirt bike tire. It is also very soft, so I guess we will see how long it will last.

I took the bike out for a ride, and this is what it looks like now:

I didn't get very long before I blew some mosfets in the controller, and without any way of disconnecting the controller it was a slow walk of shame to get home..

Well, I thought without any way to ride any more I could as well install the hubsinks:

Merlin, they still fits with a 16" rim :wink:

 

[rockstar195]

I like the width of the tire, but it is more like a moped tire with coarser pattern. It doesn't have the side protection of a real dirt bike tire. It is also very soft, so I guess we will see how long it will last.

I took the bike out for a ride, and this is what it looks like now:

I didn't get very long before I blew some mosfets in the controller, and without any way of disconnecting the controller it was a slow walk of shame to get home..

Well, I thought without any way to ride any more I could as well install the hubsinks:

Merlin, they still fits with a 16" rim :wink:

Hey nice fenders, what kind/type, where to buy from?

 

[j bjork]

You cant buy those. The front fender I have made myself in fiberglss, and the rear fender is a modified moped fender.
If you read the tread you can see how I have made them.

 

[sn0wchyld]

Yes, I am grateful for your input. I have limited experience with 2-wheelers. It would be interesting if more people with experience would share their thoughts.

If I go with the custom drilled rim I guess they take the spoke angles in consideration, that would be the whole purpose. But it is just what the company suggested. Maybe excel will say it cant be done, or that it is unsuitable with a cross pattern.

I cant see the picture unfortunately.

The 16" will be a little bigger in diameter than the 17" I had, if I go 17" or even 18" and mx rear tire it will be bigger still.
As it was, the controller overheated easily, that will probably change when I get the nucular 24fet. But the motor is not far behind in heat, so that will probably be the next problem.. I already have statoraid, I can go with hubsinks too. But I don´t think they will do very much difference, because the outer shell on the motor is seldom much over 50c.

I asked about a 1,6x17" excel rim, but it was more expensive than the 1,85x16", at least from the swedish company.

I mean, bigger wheel diameter is not such a big deal for you. You have a middrive and can change gearing. It will still be heavier and more rubbing(?), but at least you don´t have to get lower motor rpm.

Another option is an sm pro 1,85x16" that they have on sale in the swedish company. It will not be custom angles, but the prize is right. Then I could test both cross and radial lacing with the spokes I have. They will be too long, but I would probably be able to see what could work.

My damage is not from jumps, it is from rocks on the trails I´m riding. I think part of the problem is the unsprung weight, about 14kg motor in the wheel..
That makes the rim take a lot more impact. I have not a single bump in the front wheel.. But sure, it is a low quality rim. A better quality rim would do a whole lot better. But I think it is a good idea to have more tire between the rim and rocks too.. Hard decisions :?

I can vouch that your original rim is down to cheapass china steel - I had the same kind of 17'' rim and the same issues. now using a 19'' rim with a 2.5'' tire, no issues whatsoever. I get you want to stay small but you've got enough motor there now. and if your temps are peaking at 100C now you still have some thermal headroom too. A new controller may actually help as they'll run the motor more efficiently. I dropped ~25C of heat from my motor just by tuning the adaptto controller to better run the motor. lots more options for tires once you got to 18 or 19'' too

as to statoraid - are you testing the motors outer temp at the magnet ring, between the spokes, or on the side cover? because the side cover will not get hot at all... but the magnet ring can. if its still that kind of temp difference then you may have statoraid stuck on the inside of your stator rather than between the magnets - if you get some more put a long thin tube on it and make sure you push the tube right through to hit the opposite side cover before putting any statoraid in - so the liquid hits the inside of the side cover, rather than the metal of the stator as may have happend in your case.

 

[j bjork]

as to statoraid - are you testing the motors outer temp at the magnet ring, between the spokes, or on the side cover? because the side cover will not get hot at all... but the magnet ring can. if its still that kind of temp difference then you may have statoraid stuck on the inside of your stator rather than between the magnets - if you get some more put a long thin tube on it and make sure you push the tube right through to hit the opposite side cover before putting any statoraid in - so the liquid hits the inside of the side cover, rather than the metal of the stator as may have happend in your case.

Interesting, I measure between the spokes. From what I remember from the statoraid thread, you could just push it in there and it should find it´s way to the magnets.
And that is what I did, and at fist it did´nt seem to make much difference. And it did´nt make any difference in no load amps. But when I had been riding a while it started the make a difference in temp, but I haven't tested no load amps again.

So you think I should get almost the same temp on the outside as on the winding's?

 

[j bjork]

Here is a post from Justin about statoraid:

Re: Definitive Tests on the Heating and Cooling of Hub Motor

by justin_le » Jul 31 2017 8:18pm

Offroader wrote:
Does anyone know how much statorade should be added to a cromotor? This is a 50mm wide stator? I'm sure this was discussed before but I can't find the info easily. Or should I do the no load current and keep adding?

It's been discussed at some length, I haven't done statorade tests on a cromotor directly yet but you can easily extrapolate from this information on MXUS motor with 45mm wide stators:
https://endless-sphere.com/forums/viewt ... 8#p1106508
and the H35XX motor with 35mm stators:
https://endless-sphere.com/forums/viewt ... 2#p1113292

There's no harm in adding too much if you don't care about the no-load drag but 8mL should be sufficient even in a larger hub like that.

Does it also matter if you drill the hole to fill it towards the center of the hub motor? I assume it doesn't matter where in the motor it is squirted in from because it finds its way to the magnets?

Correct, it really doesn't matter at all where you put the hole as the Statraode will find its way to the magnets. You just want to avoid drilling into the windings if you are making the hole with the side plate still attached.

 

[sn0wchyld]

as to statoraid - are you testing the motors outer temp at the magnet ring, between the spokes, or on the side cover? because the side cover will not get hot at all... but the magnet ring can. if its still that kind of temp difference then you may have statoraid stuck on the inside of your stator rather than between the magnets - if you get some more put a long thin tube on it and make sure you push the tube right through to hit the opposite side cover before putting any statoraid in - so the liquid hits the inside of the side cover, rather than the metal of the stator as may have happend in your case.

Interesting, I measure between the spokes. From what I remember from the statoraid thread, you could just push it in there and it should find it´s way to the magnets.
And that is what I did, and at fist it did´nt seem to make much difference. And it did´nt make any difference in no load amps. But when I had been riding a while it started the make a difference in temp, but I haven't tested no load amps again.

So you think I should get almost the same temp on the outside as on the winding's?

It probably will, but I could also see it pooling a little on the inside of the stator too if it happens to get injected right on to the stator support arms (that attach the stator to the axle) - at the very least you'll loose a ml or two by the time it works its way to the magnets. I've put the full 10ml in mine being careful to spray it direct on the inside of the opposite side cover and saw benefits almost immediately. That said, im tempted to add another 5-10ml and a second row of heat sinks and see what happens, as I still hit thermal rollback riding hard (that said, im putting in >300phA so I really shouldn't be too surprised hahah). I'd be looking at liquid cooling if I was going to be serious about keeping this bike+motor combo for my hard riding, but with a surron and a 3rd bike on the way I think i can leave it as a easy reliable commuter.

 

[j bjork]

Yes, it seems like there can be benefits with more statoraid. Justin found that he got the best effect with about 12ml in a 27mm 9c motor, so maybe about 20ml in qs 205 50H?



9C2707 0 to 18mL Statorade, Core to Shell Conducitivity.jpg
9C2707 0 to 18mL Statorade, Core to Shell Conducitivity.jpg (108.04 KiB) Viewed 2084 times

It's impressive just how much of an effect even 2mL has at the low 100 rpm point, but then this clearly ceases to do much as the motor spins up faster. Both the 4mL and 6mL fills sortof plateau around 300-400 rpm, while with >8mL the conductivity always increases with motor speed. What is really interesting is that it seems to max out around 10-12mL, and then the thermal conductivity actually decreases a bit with the 14,16 ,and 18mL fill levels. You can see this really clearly in the same data here but plotted with mL Statorade on the 'X' axis, and each of the 100, 200, 300, and 400 rpm data sets. I've got no idea at all why this would be and can't visualize a scenario where higher amounts of ferrofluid would have the effect of reducing the thermal heat transfer. It's not big enough to worry about overfilling, but it's a curiosity that I"m curious to see if will be replicated with other motor series.

 

[j bjork]

Finally the bike is up and running again after some controller problems.
I am back on the one I have ran most of the time (repaired), after some trying with two others..

The first try in the forest, so far only some small scratches in the rim
(the wire hanging down is from a computer behind the bike)

 

[j bjork]

Today it was really up to the test, riding some rocky trails. At least one time i hit a rock pretty hard, that would for sure have dented the old rim. But nothing so far on the new one