Three-Wheel Think Tank

[Smurf]

Ok, some good input so far. Do we have any sort of consensus on front suspension set-ups? I've figured the options to be:

VW Beam.
Pros: Easy. Reasonably priced. Aftermarket support.
Cons: Solid across interior space. Somewhat heavy. Not the greatest ride quality.

Custom A-Arms.
Pros: Lightweight. Cheap to build. Building the suspension to fit the car.
Cons: Possible issues with safety inspections. Lot of research and/or trial & error to get it correct.

Donor Suspension.
Pros: Front-wheel drive capability, if desired. Aftermarket support. Safest of the options.
Cons: Building the car to fit the suspension. Likely to be heavy.

Modified ATV Suspension.
Pros: Front-wheel drive capability, if desired. Cheap. Lightweight. Easy to fit.
Cons: Not high-speed capable. Matching car rims to ATV hubs.

It would be nice to have a full conversation about this, like an open source project. With the prices of fuel-efficient vehicles rising relative to gas prices, and more and more careless drivers on cell phones making motorcycles less safe, building your own small vehicle based on YOUR needs is a viable option.

[sheepdog 44]

For a two seater why a trike at all. An autocycle is more simpler, aerodynamic, cheaper, and completely more awesome to build. Running a Ninja 250cc motorcycle engine would work great because this is completely faired in where as that engine has to deal with a .5-ish cd as a standard motorcycle. MPG for it would break 100-120mpg maybe more. You could get an autocycle below .17cd, and the frontal area would be far better than a side by side trike. Side by side seating is one of those weird things people insist on, but it's hardly a sacrifice especially when your already throwing out luxury, cargo, power, handling, and a spacious interior already for a high mpg econobox.

[Smurf]

I do like the shape of that, with the inline seating. Still think two up front is the way to go because I personally am not that familiar with riding motorcycles. How does that side wing wheel thing work?

[niky]

Have always wanted to do something like this:



Probably with a Suzuki chassis with a three-cylinder motor. Then work on the aero after. Starting with a sound mechanical base allows you to concentrate on aero, which is part of the reason for going trike, right?

EDIT: This one, I think, is precisely what I want to do:



Four wheels, but narrowed rear track. You could do the rear wheel with a motorcycle swingarm instead. Should be super light.

[sheepdog 44]

Originally Posted by Smurf

I do like the shape of that, with the inline seating. Still think two up front is the way to go because I personally am not that familiar with riding motorcycles. How does that side wing wheel thing work?

It's basically an elongated motorcycle with a steering wheel. The outrigger wheels are on either side. The suspension is set up that either outrigger wheel is barely just off the ground, so in cruising only one outrigger will be be touching the ground but you can't really tell which one. It keeps it in a completely vertical position at all times. There is no leaning into turns. At any given moment it is a trike which is why i think it fits here.

The original ones were handmade which goes to show how simple it is. Some had 600-1000cc engines. One i believe did get 100mpg, but i'm not sure what size the engine was.

[TedV]

Unless they have come up with a solution, the T-Rex is notorious for eating the rear axle bearings in 5k miles. That sounds like a maintenance issue to me. Replace bearings at every oil change?? BMW and Harley I believe were designed to be able to run side cars where the axles will get side loading. Bikes usually only see a verticle loading to the axle bearings. If axle bearings arnt designed to take side loading, early failure is a possibility. There is a few kit trikes from europe that use the BMW drive.

Look into the stability of trikes. I haven't looked at the links posted but I did do a decent amount of research a few years ago. Obviously reverse trike is more stable under braking plus turning and fits the aero tear drop better. Center of gravity needs to stay in the center of triangle to slightly forward of center of triangle for best stability. Local state laws can be frustrating to tag it since some states only concider 2 rear wheels a trike to get motorcycle tag. You also have to have motorcycle license to drive it, even tho it drives like a car

[Michael Moore]

Originally Posted by TedV

BMW and Harley I believe were designed to be able to run side cars where the axles will get side loading. Bikes usually only see a verticle loading to the axle bearings. If axle bearings arnt designed to take side loading, early failure is a possibility. There is a few kit trikes from europe that use the BMW drive.

Old BMWs (like /2s) but I would be surprised if BMW approves of putting an outfit to any of their modern bikes. Wheels with taper roller bearings will do better on axial thrust loads than those with regular ball bearings.

You also have to have motorcycle license to drive it, even tho it drives like a car

And your state may also require you to wear a helmet inside that "motorcycle".

cheers,
Michael

[Smurf]

Niky, those vehicles are one thing I thought of doing. Get a Metro/Suzuki XFi and build a custom body 3 wheeler off of it. Legally, that would help because you'd have an existing VIN plate, and all the front parts are DOT approved already. But I don't think I would keep the existing front sheetmetal because the 'seam' between car and bike always looks funny to me. But if you have an XFi Metro, and reduce ~25% of the weight, 25% of the wheel drag... Should add up to some good MPGs, right?

[Smurf]

Sheepdog, that is a very interesting concept. I like the simplicity of it, no rocket science involved.

TedV, I've heard of the TRex bearing issue, and it is a concern. But I would imagine it's more of a concern when using an existing motorcycle swingarm, if someone was to build a swingarm that is purpose built for side loads, with appropriate bearings as Michael said, it could be improved.

And Michael, I believe you are correct about the helmet in certain states. As far as I can tell, Wisconsin (my new home in a few weeks) is fairly lenient when it comes to home-built vehicles. Some states require an open roof for it to be a motorcycle, and in those cases, sometimes you then need a helmet. I believe Wisconsin says if you have a windscreen you're okay, as the concern is mainly wind/bugs in the drivers eyes. More research is needed in this area though

[Smurf]

(triple-post, my apologies)



Been messing around designing what a dash and interior might look like for a one-seater. This one is designed to fit within a chassis frame that's 30" inner width. Can't really think of what else a person would need in there...

MP3 player dock (Blackberry?), two USB ports, master On/Off switch
MPGuino with buttons
Headlights On/Off
Dome Light On/Off
Hazard button
Oil Temp digital gauge
Fuel Level gauge
Voltmeter digital gauge
Speedometer/Odometer
Brights indicator
Gear indicator
Tachometer
Electric engine fan On/Off switch
Active Grill Block On/off switch
Exterior air temp digital gauge
Water temp digital gauge
Engine bay air temp digital gauge
Intake air temp digital gauge
Ignition key
4.3" touchscreen GPS, On/off switch
Rocker gear shift linked to motorcycle trans

Has 22" width seat with 3" wide armrests on each side. But no cupholder!