Bike Pusher

Discussions related to motors other than hub motors.
This includes R/C motors, botttom bracket, roller and geared drives.
Post Reply
User avatar
Astropower   1 mW

1 mW
Posts: 13
Joined: Apr 04 2012 1:38am
Location: Israel

Bike Pusher

Post by Astropower » Sep 04 2014 7:29am

Hello there,

I am thinking about building some device to let me feel like ebike, but device which can connect and disconnect quickly from the bike easily.
so i am thinking about e-trailer or friction motor.

what you would suggest me?

TNX
Last edited by Astropower on Sep 08 2014 1:50pm, edited 1 time in total.

User avatar
amberwolf   100 GW

100 GW
Posts: 30495
Joined: Aug 17 2009 6:43am
Location: Phoenix, AZ, USA, Earth, Sol, Local Bubble, Orion Arm, Milky Way, Local Group
Contact:

Re: DIY Project

Post by amberwolf » Sep 04 2014 2:26pm

Kepler's E-boost would probably do it. Should be a link in his signature.

User avatar
Astropower   1 mW

1 mW
Posts: 13
Joined: Apr 04 2012 1:38am
Location: Israel

Re: DIY Project

Post by Astropower » Sep 06 2014 3:23am

I got some idea, i draw it.

this my idea, and i will build one.

to use small hub motor, to push the bicycle.
i will buy some parts now.

Image
Attachments
1.jpg
1.jpg (63.3 KiB) Viewed 953 times

User avatar
amberwolf   100 GW

100 GW
Posts: 30495
Joined: Aug 17 2009 6:43am
Location: Phoenix, AZ, USA, Earth, Sol, Local Bubble, Orion Arm, Milky Way, Local Group
Contact:

Re: DIY Project

Post by amberwolf » Sep 06 2014 1:42pm

Keep in mind you need a lot of weight on the motor to get any traction out of it using it like that. There are some other problems you may have doing it that way, too. Read up here on ES on the various powered assist trailers, especially single-wheel trailers, and BOB trailers, to get an idea of the issues involved.

User avatar
Astropower   1 mW

1 mW
Posts: 13
Joined: Apr 04 2012 1:38am
Location: Israel

Re: DIY Project

Post by Astropower » Sep 07 2014 7:13am

Hi,

Thanks for your advice.

Theoretically, Wheel with good grip should done it pretty well,

by the drawing we can see, if the front wheel cannot move, distance of the two wheels (blue lines) will generate angular strength (purple line),
and when the hub motor, will start pushing, the green force will start to apply - motor push forward and back wheel will start lose weight. which lead to yellow force start to work. means bike start to forward, and hub motor will have more traction.

this is theoretical only, i will test is soon.

Image
Attachments
2.jpg
2.jpg (51.55 KiB) Viewed 952 times

User avatar
Astropower   1 mW

1 mW
Posts: 13
Joined: Apr 04 2012 1:38am
Location: Israel

Re: DIY Project

Post by Astropower » Sep 08 2014 1:43pm

Step one,

i got the Hub motor about 9-8 inch size, 36V 250W.
i build somes simple device, to connect the motor to bike axis.

soon i will connect to controller and battery, and test it.

here the pictures:
Image
Image
Image
Image
Image
Image
Image
Image
Image
Attachments
1.jpg
2.jpg
3.jpg
5.jpg
6.jpg
7.jpg
8.jpg
9.jpg
4.jpg

tahustvedt   10 kW

10 kW
Posts: 595
Joined: May 26 2014 9:31am
Location: Northern Norway

Re: Bike Pusher

Post by tahustvedt » Sep 09 2014 1:54am

What about turning? Does the motor wheel skid or do ou have a spherical bearing in the dropout hinge?

yawstick   100 W

100 W
Posts: 122
Joined: Oct 31 2013 3:41am
Location: Spartanburg SC
Contact:

Re: Bike Pusher

Post by yawstick » Sep 09 2014 6:02am

Thats pretty slick... I think I would have arms from both sides of the bike.... and have battery sitting on top of it. I think skidding will be minimal once underway but at very low speed such as maneuvering it around may have a tendency to want to break the arm off at the attachment point. Would be very easy to have it where you could rotate it up off the ground until ready to go. Interested to see how this turns out.

User avatar
dingoEsride   100 kW

100 kW
Posts: 1124
Joined: Apr 15 2010 2:09am
Location: Perth, Australia
Contact:

Re: Bike Pusher

Post by dingoEsride » Sep 09 2014 8:58am

It looks like from here it would be simpler to apply the pressure to the wheel not the road in reverse, ratio should be the same, traction will still be an issue, btw I like that little hub motor
ride like the wind

JEB   100 W

100 W
Posts: 287
Joined: Jul 19 2007 5:47pm
Location: Santa Barbara Ca

Re: Bike Pusher

Post by JEB » Sep 09 2014 3:12pm

My experience you need traction but get a lot of bounce, you need to spring load it down, or add some weight, like batteries, but then add a suspension frame (to hold batteries), a tire with a lot of rubber/air is a bouncing ball, on a rough road it will spend a lot of time in the air, not road.

User avatar
gogo   10 MW

10 MW
Posts: 2471
Joined: Mar 17 2008 2:20pm
Location: Iowa USA

Re: Bike Pusher

Post by gogo » Sep 09 2014 3:22pm

If bounce is a problem you could always make a friction drive onto the back bicycle wheel.
"A conclusion is the place where you got tired of thinking." -Steven Wright

Hillhater   100 GW

100 GW
Posts: 10915
Joined: Aug 03 2010 10:33pm
Location: Sydney ..(Hilly part !) .. Australia/ Down under !

Re: Bike Pusher

Post by Hillhater » Sep 09 2014 8:50pm

dingoEsride wrote:It looks like from here it would be simpler to apply the pressure to the wheel not the road in reverse, ratio should be the same, traction will still be an issue, btw I like that little hub motor
++1^^
Change it to a friction drive direct onto the tyre.
Much less issues, just relocate the pivot point.
Also, it makes no difference if the link arm is curved or just straight !
This forum owes its existence to Justin of ebikes.ca

User avatar
johnrobholmes   1.21 GW

1.21 GW
Posts: 3955
Joined: Jul 07 2008 2:19pm
Location: Missouri
Contact:

Re: Bike Pusher

Post by johnrobholmes » Sep 09 2014 9:04pm

I built a pusher out of this trailer

http://www.mayacycle.com/


Perfect steering angle and got plenty of traction with the battery in the trailer. It felt extremely stable while powering during turns and never made me nervous of high or low sides.

yawstick   100 W

100 W
Posts: 122
Joined: Oct 31 2013 3:41am
Location: Spartanburg SC
Contact:

Re: Bike Pusher

Post by yawstick » Sep 10 2014 1:41am

johnrobholmes wrote:I built a pusher out of this trailer

http://www.mayacycle.com/

Perfect steering angle and got plenty of traction with the battery in the trailer. It felt extremely stable while powering during turns and never made me nervous of high or low sides.
Well that pretty effectively shows the kind of geometry you need on your pusher. Doubling as a trailer that would bolt to a trike or a bike is pretty dang handy.

User avatar
Astropower   1 mW

1 mW
Posts: 13
Joined: Apr 04 2012 1:38am
Location: Israel

Re: Bike Pusher

Post by Astropower » Sep 10 2014 3:04am

Hello,

Thanka all for sharing your thoughts and your opinions, i'm sure it would help me improve this thing.

I really dont like much the friction drive, because several reasons:
1. RC motor generate lot of noice because high RPM. i like the quiet of gearless hubmotor.
2. Need some mechanics system to make good pressure to able friction between the motor and wheel, which not easy to install and each bicycle.
3. Friction driver, not support bicycle with wheel cover (which protect from water and mud)
4. Absence of good friction, will cause tire damage.
5. I am using off road tire on my bicycle, off-road tire + Friction driver = not good combination in simple words.
6. Friction driver will suffer on wet or muddy rid.

Despite all this, i like the idea of small and light weight thinks, so think i have solution for most of the problems of friction driver, maybe it will be my next project :).

for now, some updates,
i purchase cheap chinese controler 350W and RC Lipo batteries, 3x 14.4V 2200mA = 43.2V 2200mA.
here some pictures:
Image
Image
Image
Attachments
21.jpg
21.jpg (161.67 KiB) Viewed 952 times
22.jpg
22.jpg (163.97 KiB) Viewed 952 times
23.jpg
23.jpg (153.44 KiB) Viewed 952 times

User avatar
Astropower   1 mW

1 mW
Posts: 13
Joined: Apr 04 2012 1:38am
Location: Israel

Re: Bike Pusher

Post by Astropower » Sep 10 2014 3:29am

Now i need to solve some issue on the turns, that the hubwheel not be draged.

About the friction between the hubmotor and the road, test results:
Zero speed - only 30% power is available, more than that, the tire starting to slipping.
About 2-3MPH (3-5Km/H) 50% power is available.
About 10MPH (16Km/h) 85-90% power is available.
About 15MPH and up (24Km/h) all the power is available.

Hubmotor weight about 3.5KG (7.7 pounds).
This results on standard road.

Here I made my first experiment on my wife,
She like it :)
Video:
http://vimeo.com/105734039

Hillhater   100 GW

100 GW
Posts: 10915
Joined: Aug 03 2010 10:33pm
Location: Sydney ..(Hilly part !) .. Australia/ Down under !

Re: Bike Pusher

Post by Hillhater » Sep 10 2014 3:48am

Astropower wrote:Hello,

Thanka all for sharing your thoughts and your opinions, i'm sure it would help me improve this thing.

I really dont like much the friction drive, because several reasons:
1. RC motor generate lot of noice because high RPM. i like the quiet of gearless hubmotor.
2. Need some mechanics system to make good pressure to able friction between the motor and wheel, which not easy to install and each bicycle.
3. Friction driver, not support bicycle with wheel cover (which protect from water and mud)
4. Absence of good friction, will cause tire damage.
5. I am using off road tire on my bicycle, off-road tire + Friction driver = not good combination in simple words.
6. Friction driver will suffer on wet or muddy rid.

Despite all this, i like the idea of small and light weight thinks, so think i have solution for most of the problems of friction driver, maybe it will be my next project :).
You miss understand.
The suggestion was to use your existing small hub motor and tyre as the friction drive onto the tyre instead of the road.
With some attention to getting the correct pivot location , it will avoid most of those reasons you listed above.
It will also ovoid the problem of scrub when you turn.
This forum owes its existence to Justin of ebikes.ca

User avatar
Astropower   1 mW

1 mW
Posts: 13
Joined: Apr 04 2012 1:38am
Location: Israel

Re: Bike Pusher

Post by Astropower » Sep 10 2014 9:17am

Hello Hilter,

You are right,
This will solve me the problems in section 1, 5 & 6. and will increase the problem in section 2.
In my next project I'll think about something like this :).

Hillhater   100 GW

100 GW
Posts: 10915
Joined: Aug 03 2010 10:33pm
Location: Sydney ..(Hilly part !) .. Australia/ Down under !

Re: Bike Pusher

Post by Hillhater » Sep 11 2014 1:51am

Astropower wrote:Hello Hilter,

You are right,
This will solve me the problems in section 1, 5 & 6. and will increase the problem in section 2.
In my next project I'll think about something like this :).
With a careful position of the arm pivot point, the drive wheel will generate its own load force vector onto the tyre, and solve your problem no 2 .!
Read the friction drive threads if you do not understand the principle of non concentric arc,s for the drive mount.
Also you could arrange it to be behind the rear of the tyre cover (problem 3).
This forum owes its existence to Justin of ebikes.ca

Post Reply