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View Full Version : AZ chopper forks strong enough for 750 W motor



socialtalker
05-26-2014, 10:02 PM
I had an unplanned layoff from building since lat october, a full 8 months. I still dont have time for bike building but i will try to squeeze it in.The only thing I did this overlay was save up for the motor for the delta runner. I just have a question for anybody, but i will direct it to Brad because I really need an answer. I have about 9 AZ plans, but none that includes your Chopper Fork, Will any of your Forks hold up to a 750 Watt motor with a 203 mm disk rotor on it?

socialtalker
05-27-2014, 08:56 PM
anybody?.....

Radical Brad
05-27-2014, 09:01 PM
being made of 1.5 inch tubing, they would have no issues as long as you secured the torque arm and made sure your dropout welds were Grade-A.
The stress on the head tube and quirky handling of a chopper.... now that would be a concern.


Brad

Ticktock
05-28-2014, 07:48 AM
Hi ST,
you may have accidentally led us all astray!!! The thread tittle says "Chopper" forks, but you are building a Delta runner! Big difference.
Brads answer was directed at the chopper.
My first question is just a check---is 750 watt really legal where you are ? I don't need to know--just making sure you know to check.
Provided you have steel forks on the delta runner, they should handle any legal motor you fit, as many others have done it before you.
Do not fit any hub motor to alloy, or alloy suspension forks---Brad has the photos to show you why--it could be painful!
The lack of answers was probably because not too many have fitted hub motors to a chopper---don't know--just a guess.
Steve G

socialtalker
05-28-2014, 06:39 PM
Thanks for responding.
I learned a long time ago what Brad said about alloy forks, I never intended on using them with a motor.
I had a steel non chopper fork lined up to use, until the motor came. I tried a fitting and found that the motor with a disk rotor mounted on it didnt fit, about a half inch too narrow. Non of the other forks fit either, no heavy drop out. not steel, too narrow, not 26 inches. I couldnt find a fork anywhere that was 4.5 inches wide, all steel, heavy drop outs, for a 26 inch wheel. I had not seen anyone build anything else but a chopper fork, I have no experience with them. i didnt know they had quirky handling like you mentioned. i have not seen instructions for any other kind of fork. I see instructions on how to lengthen a fork, but not make it wider.

I didnt know the stresses on a head tube are different on a chopper fork than a regular fork, more stress?

I was looking at the forks that had these metal plates, where the tubes are fitted thru the plates.
http://www.chopperresource.co.uk/my_uploads/products/mar06_ng1_big.jpg
but i do not have instructions on how the middle threaded tube is fitted in. then i remembered the atomic zombie forks. where everything is simply welded together.

As for welding, I had had planned to tack weld up a fork then take it to the professional welder who did my hub/axles.

I know a tube bender who could perhaps bend a u shape 4.5 inches wide and see if i could make a fork from that, hadn't thought of that.

the only requirement for michigan for motorized bikes that i found is they cant go over 20 mph, i looked that up years ago.
http://www.ampbros.com/?page_id=8
I dont think mine will go over 20 after being fully assembled, for a lighter bike, it 750 might be too much.






being made of 1.5 inch tubing, they would have no issues as long as you secured the torque arm and made sure your dropout welds were Grade-A.
The stress on the head tube and quirky handling of a chopper.... now that would be a concern.


Brad


Hi ST,
you may have accidentally led us all astray!!! The thread tittle says "Chopper" forks, but you are building a Delta runner! Big difference.
Brads answer was directed at the chopper.
My first question is just a check---is 750 watt really legal where you are ? I don't need to know--just making sure you know to check.
Provided you have steel forks on the delta runner, they should handle any legal motor you fit, as many others have done it before you.
Do not fit any hub motor to alloy, or alloy suspension forks---Brad has the photos to show you why--it could be painful!
The lack of answers was probably because not too many have fitted hub motors to a chopper---don't know--just a guess.
Steve G

Ticktock
05-29-2014, 07:41 AM
Hi again,
If you are buiding a set of "normal" shape forks for a Delta wolf, using "chopper" size material, and do a good job welding it all up, I can't see any problem with handling or strength.
Confusion is coming from the chopper fork concept---usually long extended forks, not really suited to front drive. Delta wolf is usually more normal shape forks and front end geometry,
so should be no problem with front drive, especially on a trike.
Steve G

socialtalker
05-31-2014, 01:39 AM
Hi Steve:

the trike i am talking about is a is a delta runner, not a delta wolf. the angle of the head tube is already welded on at 66 degrees. I dont think i could the really long fork on it even if i wanted to.

I was thinking of a triple tree fork like Charlie_r has on his lode runner:
http://forum.atomiczombie.com/gallery/files/1/5/4/8/p1010971.jpg

made from one of brads chopper plans that is shorten to this length, but at least long enough for a headlight and front fender. made of steel and have heavy drop outs.

bottom line its looks like i am gonna have to put together at least 2 different style of forks and test them.
Looking also to see if I can make them out of high carbon steel. I haven't priced that or talked to the professional welder yet.