Been drifting about the site for awhile, figured I'd lay out my plans with the hope of others' insight and experence. My build will use a Fiero and a liter plus bike.
My last build was a v8 fiero, sold off to ebay land some time ago. Looking for the next build, an have settled on an RT. Progress on the RT will be slow, and documented here for all, but I cant start until fall.
I will start with the Fiero, have been looking for an 84-87, I'm going to avoid the 88's, as they have 1 year only bearings.
Once purchased, the car will be stripped and hacked to bare minimum, I may just wind up using the components and building the frame.
Some questions for the forum: Shaft or chain drive? Why?
What is the best way to shorten / remove the swingarm? I think some of the trikes out there seem too long, I intend to shorten my bike as much as possible, I may even make the engine/wheel fixed, and have it move as one part.
Hopefully you'll join in, and thanks for any advice.
Last Edit: Jan 29, 2012 12:05:47 GMT -5 by jokerb90
Post by triplethreat on Jan 29, 2012 13:53:17 GMT -5
Hello jokerb90. I'm kinda new here too. I agree that a shortened swing arm is better for trikes. I think bikes have those long arms mostly to prevent wheelies, not much of a problem for trikes. It exagerates the the already odd proportions of a trike. Shortening one would be a major problem as they are usually aluminum and their elements do not taper linearly making taking a section out difficult. I made my own but I must say it was not easy. I think that is why most builders just stay with the stock arm.
Post by scooterrebel on Jan 29, 2012 15:22:21 GMT -5
Sounds like a good project.
My complaint about a lot of RT's is that they just look the part of a motorcycle grafted onto the back of a car. Making your own swing arm might give you a shot at getting the proportions right and solving the look issue for me.
I have thought about this quite a lot. My fix is to have the frame setup where a short swing-arm can be bolted to the frame in a way that sets up the pivot point exactly centered on the engine sprocket center-line. My idea is to have the tire within 2-3 inches of the back of the motor(just enough room for a fender of sorts). By making the frame wider than the cycle engine you can make the swing-arm accommodate any width of tire you want. Setting up a sprocket with a hub style extension will put the chain outside of the tire, and you will probably need to offset the engine to line up the engine sprocket with the wheel sprocket. Then you might need to move the rest of the engine compartments hardware ( battery, radiator, etc) around to balance the trike better.
I dabbled with shaft and chain drive for my electric RT layout using various motor bike swing arm set ups. In the end I went for a home made single sided swing arm to carry a chain drive and a 15x7" wire wheel from a Morgan.
The swing arm will pivot on the same axis as the motor armature on the back of the chassis frame.
This is a plan view of the relative positions of the wheel and motor.
This is the start of the swing arm fabrication.
This a 2D layout on the bench to work out the chain length.
Post by triplethreat on Mar 17, 2012 13:40:36 GMT -5
I have been thinking along the lines of what srx660 is describing but taking it one step farther with a 4 link system, sort of like a double wishbone but operating with upper and lower arms lengthwise instead of 90 deg to the frame like the front. Pivots would be above and below the sprockets on both ends working in parallel with the chain. This would keep the distance constant between the sprockets as the rear goes up and down. Chain life would be extended and needed adjustments rare.
The main reason I'm thinking about going to this it to counter the jacking action I get with on/off throttle. With a conventional swingarm the tire rotates forward as it moves through its arc. With a 4 link this is eliminated as the tire just moves up and down. This is why BMW invented and uses the Paralever. Yes, I know, BMWs use shafts, but the same principles would seem to apply.
My main concern is getting enough stiffness out the arms to keep the tire from twisting them under the high lateral loads you get with a trike.