frame design

this is my design for the frame i am building what do you think, as this is the first one i have built. i am a welder fab by trade so should be easy to build but any comments welcome. this is for 24in wheels and the 140mm rear wheel spacing. there is 6 battery pack and the top box is the controller if you can see the lines, do you think there will be to much heat from the controller. i was thinking of drilling vent hole infront and behind the controller.
adam

I think you'd be better off asking this question at an engineering forum or a welding forum at least. This cardboard layout doesn't mean much. What the bigger concern is is frame strength. Wrong materials and incorrect material thickness can mean frame failure. That'd be bad news. Not much else to say, it looks a lot like the frame design you'd see in any big box store.

"do you think there will be to much heat from the controller" That is a super variable question and an impossible one to answer. Are you saying you want to drill a hole into the controller or into the frame?

I want to say you want to drill those holes into the frame, but it doesn't really make much sense to me either way. I imagine a larger controller, or a controller capable of handling more amps than you'll use will make it run with less heat, I could be wrong, I have no knowledge on that. What I am trying to say is, some controllers are made for 20amps, then they often go up in capacity in 5 amps, 20, 25, 30, 35, 40 and so on. I imagine a larger amp capacity would mean the power is going over a larger area, and the heat would at least be more evenly distributed.

If you end up setting up the controller and it is getting very hot, you could move it to a rear rack or something and instead of having it face forward it could face to the side, so that it was hanging to the left and right of the frame, and in the wind.

Hi,

So far so good, except for one thing the rack angle (fork) is incorrect and the position of your crank set vs the pivot point of the swing arm, see Stealth Fighter for correct positioning on both issues.

Good day!
Black Arrow

Looks like a good basic design.

The steering angle looks fairly verticle. it should be somewhere between 20 to 25 degrees back from verticle. the more angle, the more stable it will be at speed but the less manuverable at lower speed.

I don't see an issue with the bottom pivot placement, although you may need to adjust the right side arm, as it will likely hit the chain. you can have the arm come down, then go back to the axle, like is done on bikes Like Kona Stinkys, and others.

The bigger issue is the shock placement. The ratio between the amount the rear wheel moves up and down and the amount the shock compresses will be way to high with the shock attached to the swing arm there. You'll likely end up with a shock that collapses, or need a spring so stiff it defeats the dampening of the shock with it placed there.

I'd add a built in rear rack. I understand the battery won't go there, but if nothing else, you want a place to carry a drink of water, a pump, and that jacket you needed in the morning but don't want now.

Sure, you could use a seatpost rack, but a built in one would be nice, and you could integrate a mud fender into it. I'm assuming this bike would be ridden in dirt, mud, etc at times, so a rear fender is a worthwhile feature.

thanks guys i have tweak the design abit and now started making it, i have put a pic in (E-Bike Photos & Video) i still have a load to do but i am hoping to have the main body finished tomorrow, i want to make it in alloy after a bit of testing to get rid of any problems.
adam

welcome to the forum adam...

Are you making a jig or just this first frame as a prototype?

migueralliart said:

welcome to the forum adam...

Are you making a jig or just this first frame as a prototype?

Click to expand...

i have a full size motorbike build jig that i have adapted for now to set it up and keep it all in line, but i have made cad drawing for it so later i will get it laser cut. for now i have just plasma cut it all out as it just keeping the cost down for now until i have tweaked the design. iam using this as a test to make sure it all fits and the suspension works well. then i am going to make it out of alloy to make it nice and light, but i might have to add a few bits here and there to keep the strength when in aluminium.
adam