No F*ing idea Friction drive

[Bluefang]

ROFL, nice story.


Ohh well $40 for a motor down the drain, atleast it provided proof of concept. I guess i ll buy one of the bigger ones to play with now, bigger bearings will be cheaper if i screw them up again right :lol:

Now i have to find a good full suspension bike with disc brakes locally or i can just get parts to fix up the pictured bike and add discs, but its a no name chinese bike and the crank is buggered, loose and sloppy. So i think it will be cheaper getting something from Ebay.

 

[amberwolf]

Crank being loose is probably easy to fix; take a look at the crank and/or bottom bracket articles on Sheldon Brown's site. Might not even need any special tools.

 

[dontsendbubbamail]

ROFL, nice story.


Ohh well $40 for a motor down the drain, atleast it provided proof of concept. I guess i ll buy one of the bigger ones to play with now, bigger bearings will be cheaper if i screw them up again right :lol:

Now i have to find a good full suspension bike with disc brakes locally or i can just get parts to fix up the pictured bike and add discs, but its a no name chinese bike and the crank is buggered, loose and sloppy. So i think it will be cheaper getting something from Ebay.

I think you can buy the bearings from VXB.com for less then the cost of the motor.

Bubba

 

[Jeremy Harris]

The bearings in these motors are notorious for being a bit iffy, many people (including me) routinely replace them with decent brand name bearings from the off. Decent bearings needn't be too expensive, as you don't need any super-duper, close tolerance bearing, pretty much any decent brand name of stock bearing will be much better than the bearings that came with the motor.

Out of six motors I've found the following:

- In one motor the bearings at one end were full of glue and the balls weren't spinning in the race.

- Two motors had bearings that were completely without any lubrication at all.

- One had an obviously brinelled bearing from where pressure had been applied to the outer race when pushing it on to the shaft during assembly.

So far, the only motors I've had with good bearings are the Collosus units, which are fitted with nice NSK bearings.

Jeremy

 

[ktronik]

No good, bearings are a real pain sometimes!!

Jerermy, you think it's worth replacing berings before they die, or after?? As would not want to kill my motor with heat, from excess current due to it being hard to turn

k

 

[Jeremy Harris]

My experience with Chinese motors is a poor sample to judge them all from, but there's evidence from the RC crowd that these Chinese motors do seem to suffer a higher than expected rate of bearing failure, so my personal preference is to replace the bearings from from new. Having said that, I would be pulling any new motor apart anyway, as I run Hall sensors on everything, so the extra work in changing the bearings is minimal.

Jeremy

 

[ktronik]

Very good, thank you sir!!

K

 

[ktronik]

Hey bluefang, as a bike mechanic, I can tell you you ain't gunna get disks on that baby, no disk
tabs

a cell bike is cheap ok parts with a really cheap frame, but does have disk tabs

any bike questions/pic happy to have a look at

k

ROFL, nice story.


Ohh well $40 for a motor down the drain, atleast it provided proof of concept. I guess i ll buy one of the bigger ones to play with now, bigger bearings will be cheaper if i screw them up again right :lol:

Now i have to find a good full suspension bike with disc brakes locally or i can just get parts to fix up the pictured bike and add discs, but its a no name chinese bike and the crank is buggered, loose and sloppy. So i think it will be cheaper getting something from Ebay.

 

[amberwolf]

Hey bluefang, as a bike mechanic, I can tell you you ain't gunna get disks on that baby, no disk
tabs

Well, that can be fixed, you know.

If it was steel, they could be welded on (which is what I'll be doing to CrazyBike2 eventually, most likely).

If the dropouts are the right shape then ChoppersUS has a caliper holder that bolts to them.
http://www.choppersus.com/store/product/307/Disc-Brake-Bracket-Billet/
Dunno how well it works; I have pondered copying the thing and testing it as a second set of brakes on CB2, but never have gotten round to it.

 

[Hillhater]

If the dropouts are the right shape then ChoppersUS has a caliper holder that bolts to them.
http://www.choppersus.com/store/product/307/Disc-Brake-Bracket-Billet/
Dunno how well it works; I have pondered copying the thing and testing it as a second set of brakes on CB2, but never have gotten round to it.

Ahh !! thanks for finding that.
I had pondered making that kind of adaptor and even had asked several bike shops if they could find me something similar.
but all i got was blank stares and the old line .."it cannot be done", or ... "you will need a new frame" ... etc etc.

 

[amberwolf]

First time I saw that (I think AJ pointed me at it), a huge bright searchlight came on in my head. Unfortunately the power company was sure something was wrong and flipped a breaker somewhere, so it didn't last long, but I got some of the idea back and figured on making a version of that which would basically be a copy in steel plate of my dropouts' shape along with the shape of that bracket, silhouetted together, and then bolting thru the holes that line up with the fender mounts, plus the axle dropout slot, would keep it from ever being able to pivot around the axle (hopefully), and also wouldnt' cause problems taking the wheel off for spoke replacements and stuff.

 

[Bluefang]

Ok, i pulled my motor apart to get at the bearings, got all 3 bearings out pretty easy. They all seem to move freely, but the bigger one has 2 slight dimples on it.

but i think i may have a bigger problem and might need a new motor anyway, 2 sections of wire directly opposite in my motor seem to be burned, one pretty bad(the pictured one). I tried to take my motor to a motor rewind place to check the resistance of each phase but they had no idea about my motor and were quoting $50 for me to leave it and they would find out whats wrong with it, or $400 for a rewind......wtf. Pitty my cheapo voltmeter will only measure down to half a ohm, and not into milli ohms.

I am probably going to toss that bike frame i have or i ll fix it up and sell it on Ebay, i have decide i ll take my time with the bike i have and get everything sorted properly, once i get back i ll start looking into building a bike like the cafe racer pictured but with pedals, not that i would use them much other for the initial rolling start Should really make use of the course i did on welding lol

 

[EVTodd]

Very cool! I'm surprised you don't see more people doing the cafe racer style on here. I personally love it even though I'm getting to the point in my life where I hate being bent over that far on a bike.

 

[Bluefang]

An update on my friction drive build.

It is now working perfectly, the motor i had before seems to have been a dud with a short in one of the phases or something. The new motor worked first go when i plugged everything in and set the hall sensor ring the same as how i had it previously on the other motor. Now with a no load draw of 1.6A at about 15V. I have been running the bike around the block set for about 50% which gives me a speed of about 20mph and the motor barely reached above ambient temperature.
I had to modify the mounting i had been using to stop everything from flexing to the sides and running the roller off the tire, so soon i ll be able to try out 100% power and see how much i can get out of the motor before it starts getting too hot.
Anyone have any suggestions of some fan blades that i can bolt to the bell of the motor to draw air from inside the motor and blow it away?

Love these RC motors and my EV grin is only going to get bigger from now on

 

[spinningmagnets]

concerning air-cooling fans, axials work poorly for this, whether pushing or pulling (shaped like the air-fan sitting on a desk). An enshrouded radial (air is flung from the center outwards) will work the best. Try different fans and do a smoke test, blow smoke through a straw to see where it is drawn in, and how effectively its thrown out.

A vented front brake disc is an enshrouded radial fan:

 

[Bluefang]

I was hoping one of the RC experts might know of a radial fan that has 4 mounting holes on it to mount it directly to the bell of the motor, building my own would be increadably hard with basic hand tools to ensure it was level, otherwise i would of made one out of a fan from a PC hard drive flat blower such as http://cgi.ebay.com.au/PC-Case-Slot-CPU-HDD-Video-Card-VGA-Cooler-Blower-Fan-/130403386329?pt=LH_DefaultDomain_0&hash=item1e5ca5c3d9. On a side note, anyone know if this would run at 48V lol

Making good progress on the drive, modified it with much stonger mounting to stop it moving to the side sometimes and i ended up flipping the drive around so that the roller had a much more positive drive into the wheel, now it stays straight on the wheel and travels up to about 20mph easily, but trying to go above that the chain decides to jump off the chain ring on the roller, is there any difference between BMX chains and the average mountain bike? doesnt look that different on the bike. And with such a small chain setup should i be using a chain tensioner anyway? The chain is not too tight atm, it can be deflected about 1cm, but not enough that i can remove a link.

 

[amberwolf]

If you want a really light one that's easy to put on (but doesnt' already have 4 mounting holes centered and drilled) you can take apart almost any old dead vacuum cleaner and find at least one, sometimes two. They're usually very thin aluminum (once I found a stainless steel one), about 4-5" across and 1/2" thick, and are light enough that they can make interesting frisbees if you throw them with the open intake side up, in the normal rotating direction. .

 

[Bluefang]

Sweeettttttt

Modified the mount for the motor so i could take up the chain slack, worked perfectly and just got home from about 5min of the motor at about 36V getting me to about 30mph a few times and having some really stange looks from people i passed in the street, well it was 10pm at night, motor barely got warm even after traveling about 1 mile.

Only came home cause i have to cable tie afew wires as i almost burnt thru my hall wire cables when they were rubbing against the tire, so time to tidy the bike up and then a endurance run to see how far i can get on 12S at 5AH. I ll try and get some pictures posted soon

 

[adrian_sm]

Awesome. Congratulations.

So much for "no F*ing idea"

Adrian

 

[Bluefang]

ROFL, i am still in a fairly steep learning curve it seems, I was a bit shocked afew days ago when my bike would only travel about 2 miles before the controller would cut out from LVC, changed the programming of my controller and charged my batteries again and it still happened. Watched the Watt meter i bought and when riding my bike my batteries drained so fast it wasnt funny. Could i have frocked my batteries when i pretty much fully drained them, down to 2V a cell when i left the batteries connected to the controller for a few days when i first got everything? I have 3x4S Turnigy 5000mAH so i should get about 15-20miles at 25mph, all flats no hills where i am.

Since i frocked that up i have been playing with a 80A Mystery ESC running on a single 6S cheapo brand battery to see the difference in sensored vrs unsensored myself. But i cant get it to go past 12V when free spinning the motor, does anyone have and suggestions why that would happen. I am running a turnigy BEC and servo tester with the idea to take the output from the pot on the tester and use a push switch to turn everything on and off from the handle bars, so just as a booster that comes on when holding the switch while still been able to use the pot to control the speed, tho it will be set for max 99% of the time.

Some photos of the modifications to the mounting of my drive, it still moves to almost verticaly above the center of the wheel but now with the angle piece and the tube it stays much straighter and drives the bike much better. Mechanically everything works great and once i come back from the US(going on holidays to visit my brother in Tuscon and have some fun in Vegas, Mexico etc. So if anyone has a chain drive Ebike around there i would love to come have alook to compare with friction drives). I ll rebuild my drive system using a belt drive to make it much more compact and quieter, also removing the ratcheting free wheel as this is a large source of noise.