Ebike rider
1 mW
Hello . I want to install a motor 1000w , 48v to a bicycle , and it will be connected to the gears on the rear wheel.. so is the motor of 3500rpm ( 1000w , 48v , 2.7N.m ) is suitable ? Thanks
Last edited:
Is this motor suitable ?
- Thread starter Ebike rider
- Start date
Ebike rider
1 mW
Thanks for you first .
I want to put it near the pedal and by chain connect it to the rear gear .
My question just about that the motor is a low torque motor and high rpm and 11 teeth .
so could the rear gear of 36 teeth be enough to increase the torque and let the bike climb hard streets? No matter about speed I seek a high torque not a high speed .
Thanks for you and for every one may gives a consultation.
I want to put it near the pedal and by chain connect it to the rear gear .
My question just about that the motor is a low torque motor and high rpm and 11 teeth .
so could the rear gear of 36 teeth be enough to increase the torque and let the bike climb hard streets? No matter about speed I seek a high torque not a high speed .
Thanks for you and for every one may gives a consultation.
docw009
1 MW
Your 26" wheel only spins at 160 rpm to go 12 km/hour. While you said your motor is 3500 rpm, is it like the MY1018 which has reduction gears to slow that down to about 400-500 rpm? Otherwise, you cannot do it.
Ebike rider
1 mW
Yes sir. . Sorry I was a little busy ..
It is 20 inch . Yes it is like MY1018 but without any inrernal gear . It is 1000w!!
Do you expect that reducing rpm to 500 or 600 will increase the torque enough for slops ? Thanks brother
docw009
1 MW
It seems to me you need the gear reduction to increase the torque. I don't see how spinning it slower will work.
Ebike rider
1 mW
Thanks for you first .
I want to put it near the pedal and by chain connect it to the rear gear .
My question just about that the motor is a low torque motor and high rpm and 11 teeth .
so could the rear gear of 36 teeth be enough to increase the torque and let the bike climb hard streets? No matter about speed I seek a high torque not a high speed .
Thanks for you and for every one may gives a consultation.
Without knowing the grade of the hills, total weight of the bike and rider, wheel diameter, or other details, there's no way to tell. My guess is you'll need a 150 to 200 tooth rear if the motor is only capable of 2.7Nm, but your idea of steep may be different from mine.
Ebike rider
1 mW
Thanks brother. I think you are right. Let us say 165t. While the motor has 11t. (165/11= 15 ) , ( 3100rpm / 15=206 rpm).
That means reduce the rpm from 3100 to 206 which means incraes the torque from 2.7 to 46N.m.
Do you think 46N.m could help climbing slops ?? ( I think bike and rider are 120kg .
Do you agree ? Or it may be weak , or I need a motor of high torque and less rpm ( ratio ) .
That means reduce the rpm from 3100 to 206 which means incraes the torque from 2.7 to 46N.m.
Do you think 46N.m could help climbing slops ?? ( I think bike and rider are 120kg .
Do you agree ? Or it may be weak , or I need a motor of high torque and less rpm ( ratio ) .
docw009
1 MW
You do realize that 165T is about the same diameter as a 26" rim, if the chain link length is same as a standard bicycle chain (1/2"), I saw a post on this website where someone actually put gear teeth around the rim of his rear wheel to do this. Or it might have been a belt/pulley.
Ebike rider
1 mW
Yea yea you are right , but I did not think about that .. I want to realize that the new torque will serve me in what I want ..
About the 165t , I plan to make the pedal teeth as a mediator (11 to 60 ) then ( 13 to 29 or more ... etc ) so 3100 rpm become 200- 300 only .
Thanks for your help .. if you have additional information , I will be glad to read ..
I think 46 Newtons/meter is a little light. Don't quote me on it -- I mean I'm not positive -- but I think 60nm is more or less the minimum if you want to be able to handle the steepest inclines.
Chalo
100 TW
Torque to a small wheel gives more thrust than equal torque on a larger wheel. OP stipulated that he has 20 inch wheels.
Ebike rider
1 mW
Ebike rider
1 mW
Sure. Its 20 inch .. sure if it were more than 20 , it would need larger torque. Thanks alot sir
Wait, so why isn't 20" the standard for brand bikes?
Chalo
100 TW
Because 20" wheels have other limitations and compromises. They have reduced ride quality and traction, increased rolling resistance, limited ability to surmount obstacles, and their momma dresses them funny.
CPSC compliant e-bikes have no problem hitting their power and speed limits without resorting to small diameter wheels. However, many of the most popular turn-key e-bikes use 20x4" fat tires. Those make the hub motor work better while making the bike much worse (but the intended buyers don't know any better).
Ebike rider
1 mW
Hello sir. So also why isn't 10 , 5 the stander ?!!
Ebike rider
1 mW
Don't you sir see that 26 or 29 wheel needs more effort for riding : for ebike or normal bycycle ! And needs more torque for climbing slops ! Because it is faster depending on its longer diameter ....
On the other hand , the bike of 20 is not high , and it is low .. which makes it easer for the rider to touch the earth... etc .
Chalo
100 TW
If you think that, you haven't ridden both kinds. Bigger is always easier (with like tires).
I said so myself. That's easily correctable with gearing on a pedal bike or mid drive, but not a hub motor.
How easy it is to put feet down is a function of bottom bracket height and seat angle, not wheel size.
Ebike rider
1 mW
Thanks anywhere brother.
Notice that one pedaling means longer distance when the wheel is bigger .. which means more power !
Ebike rider
1 mW
Thanks for you
Chalo
100 TW
The motor (or your legs) only provide a fixed amount of power. The key is to match the wheel speed to the speed that amount of power can provide, in the conditions you want to ride. That's why gearing-- or changing the effective gearing by changing the wheel size-- matters so much.
Alright, I like to think of myself as a relatively smart cookie, but I have to admit that this isn't making any sense to me (and very little bothers me more than not understanding things, for better or worse). Maybe if I just ramble for a paragraph, somebody will be able to notice what I'm not getting and point it out or something.
So I'm trying to draw a force diagram in my head, and it's not saying what you're saying (like from physics 101, where you break down every force acting on an object in a given situation). On a flat stretch, gravity is doing nothing except increasing the force of friction on the tires because it's pulling them down onto the concrete. At low speeds or starting from a dead stop, the inertia seems to be the only thing resisting moving the bike. Now when it's going up a hill, gravity becomes the largest factor, and it's going to take something like the displacement distance multiplied by the cosine of the angle of the slope (or whatever it really is, it's been nearly 20 years).
Now of course a wheel isn't a perfect circle, and it deforms as it rolls. So the contact patch(es) provide rolling resistance from friction, and with a larger wheel (larger diameter but same width and type), more of a contact patch will mean an increase in resistance from friction. But it seems like that would be negligible, since the wheel doesn't slide across the pavement, it rolls across it.
I'm just totally not seeing how less torque could be required to move a bike with small wheels, but then require more force to keep it moving once it's in motion. Maybe I'm not understanding what you mean by "bigger is always easier?"
As for their mommas dressing them funny, that part I definitely get: I'd feel pretty silly cycling on 6" wheels like a Jetson has.
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