How much space

[chainmaker]

That makes perfect sense...what do you think about using that rear hoop for that chopper in the photo a couple posts back, it would be made from 1 inch emt and attached to the tail extension on the bottom and the top to the seat back??

 

[SimpleSimon]

That makes perfect sense...what do you think about using that rear hoop for that chopper in the photo a couple posts back, it would be made from 1 inch emt and attached to the tail extension on the bottom and the top to the seat back??

My concern with using EMT in high stress applications is that the wall is quite thin, and it is lo-carbon steel to start with. Personally, I'd go with 1.25 box tubing with .0625" or thicker walls. Harder to bend smoothly, yes, but overall much easier to work with than round tubing in my experience, and more than strong enough for most applications.

As I told you a few days ago I would, I have done a 3D model of a Warrior variant intended for powering with an HT engine, and with plenty of space for a jackshaft to transfer power. As drawn, the main horizontal section is 6" above the ground, with the pedal boom at 9" on its underside. The grey triangle is for the purpose of determining the Ackerman angle, which as drawn would be 12.9 degrees. Wheelbase length would be 5' 1", wheelbase width (to the center of the front wheel contact patches) would be 28", for an overall width of approx 31" to 32". As drawn, it is set up for a 26" rear and 20" front wheels.

It is my intent to do a bit more redesign on this - the current drawing is sized for a 6" wide rear dropout. I think what I'll do is redesign it with different rear bracing to the rear triangle mount point, and make it a rear suspension rig with a shock in place of the upper angled stay. By doing that the same bike frame could easily have interchangeable rear triangles for different width wheels, and only need one jackshaft positioning - just make the jackshaft long enough that the drive sprocket on it can be repositioned to allow final drive chain loops to clear the tires.

edit: chainmaker, I greatly enjoy doing these sorts of designs, and will gladly share them with anyone interested. If you'd like, I'll be happy to forward a sketchup file of my frame design as it develops. If you are not familiar with Google SketchUp, download it and learn to navigate in it - it's the best free 3D CAD program I know og, and I use it a lot

 

[chainmaker]

That is really sweet...I thought about the same thing using a swing arm of another bike to attach 2 different wheels I was thinking the upper support over the motor could be one of those atv shocks mounted to the seatback. I will try a hand at that google sketch up.And definitely I would love to see this as it develops.

 

[Stan4d]

Yeah... I spoked a 15x 10.5 wheel shell and found a hoosier drag slick to fit.

That is crazy. Crazy in the most awsome way I can think. Cannot wait to see the final build. Sorry that I posted an old quote....did not see that there was more, But after reading more,,,,,That is cool crazy.

 

[chainmaker]

I stayed up last night thinking about the interchangable rear end for a more conservative 4" rear wheel here is My what if... the bottom of the vertical fork support attach two tabs drilled 1/2 in that would attach to two 1/2 in id bronze bushings inserted in the tail extension. At the base of the forklegs attach a shock mount and an adjustable shock going to the seat back, the jackshaft would be forward of the bushing mounts??
Cheers
Chainmaker

 

[SimpleSimon]

I stayed up last night thinking about the interchangable rear end for a more conservative 4" rear wheel here is My what if... the bottom of the vertical fork support attach two tabs drilled 1/2 in that would attach to two 1/2 in id bronze bushings inserted in the tail extension. At the base of the forklegs attach a shock mount and an adjustable shock going to the seat back, the jackshaft would be forward of the bushing mounts??
Cheers
Chainmaker

Attached are a couple of views of what I am envisaging - the first is the full frame, with the open "well" behind the seat being 12" wide by 20.75", not including the triangular part where the two frame members come together with the main frame boom.

The second is that same model, in a detail close up showing the pivot hinge points for the rear yoke. As drawn, a wider yoke too accommodate a tire up to 10" wide is merely a matter of widening that rear yoke. Even wider is easily enough done by making the uprights and the rest in a slightly different configuration, while keeping the hinge points as drawn. The drawn view has 6" of open clearance in the rear yoke - which is plenty for even a fairly fat rear bike wheel. The engine "well" space is plenty roomy enough for even a Titan 4 stroke engine, or just about any engine you might reasonably want to use, plus jackshaft.

I got a wild hair yesterday, and started drawing a flat bed stake side Delta trike little hauler, if you'd like I'll post that later.

 

[chainmaker]

Simple Simon, You said " As far as final drive options go, I'd favor bringing the power and pedal drive trains together at the mid-drive, then doing a single final chain loop to the right side sprocket. That leaves the left side free for your disc brake rotor, and also puts the power through the gearing system - with that massive a rear wheel it might be very useful to have the option of shifting up/down for starts from a full stop and getting to cruising speed." I got a brain-fart and cant seem to figure out what the order of sprockets on the jackshaft would be I think....on jackshaft left side to right , chain sprocket to motor, chain sprocket to crank, gear cluster & chain to sprocket on wheel ??
Thanks
Cheers
Chainmaker

 

[chainmaker]

Anyone help with this "I got a brain-fart and cant seem to figure out what the order of sprockets on the jackshaft would be I think....on jackshaft left side to right , chain sprocket to motor,freewheel chain sprocket to crank, gear cluster & chain to sprocket on wheel ??
Thanks in advance

 

[SimpleSimon]

Sorry I didn't get back to this sooner, chainmaker.

When bringing the power and pedal sides trogether to feed through a multi-gear system for the final drive loop, the order of the sprockets is going to be a function of engine design, wheel width, and other factors, but as I see it, in the design we have been discussing, that order will be (as seen from behind the bike), engine driven sprocket -> beariing -> pedal driven sprocket -> bearing -> output sprocket, going left to right.

The output sprocket of the jackshaft goes either to the input sprocket of an internally geared hub used as a mid-drive, or to the drive sprocket of the wheel directly (perhaps through a dérailleur system). Also, the dérailleur could actually be the output procket on the jackshaft, as well.