Homebuilt Recumbent Idea & Input Needed

Wheres my dog

New Member
Local time
10:04 AM
Joined
Feb 22, 2010
Messages
477
Location
Southeast, USA
Hello All,

First let me say I live in a state with no laws regarding an MB, so I believe there would be no issues here. And this would be more of a learning experience that would hold value more then the outcome of it.

This would not be a daily road bike, more so for longer trips in the country, rather then inside the town travel.

Onhand already I have a DAX Titan 49cc engine as well as a BMP friction drive kit.


Thinking of building a somewhat simple recumbent style MB. I am thinking of a single 20" or 26" wheel in the read which will be driven by the 49cc and friction drive kit. The front would be two 20" or 26" wheels mounted on a solid axle held in place by pillow block bearings perhaps.

The main frame would be a sizable aluminum tube or steel tube. The rear drive wheel would be an adaptation of a simple front fork of a bocycle also containing a disc brake, and as a backup, a v brake as well.

Not even sure I would have any pedals per say, may just pegs for the feet, or a crank that leads chain to a freewheel sprocket under the seat hidden for the looks of pedal power.

Steering would be by two hand levers mounted on the side of the seat, and cable would be ran to the front wheels near the bearings which would be mounted on top of a separate piece of steel plating which would "float" on top of a ball bearing which would allow for turning above the main frame.

Searching the web now, but if you can visualize the bearing I need for the front end to work, could you point me to a website maybe?

Here is a link to the front wheels I would use...

http://www.northerntool.com/shop/tools/product_200331764_200331764


Any thoughts on this first take at building?

All input is appreciated...
 
Visualizing your proposed steering system, I want to ask: Why?

It seems to be unduly complicated, and fraught with technical issues. Kingpins and a drop axle T frame with an extension boom footrest/crank seems a better solution, overall. Also, with a tadpole recumbent (which is what you are describing) you need front brakes - under braking weight and load shift forward. A rear brake only will almost certainly result in rear wheel lock ups and LOOOOOOONG stopping distances.

A very straightforward hard-tail tadpole using a 1.5 inch square tube main spar and drop center axle beam is dead simple to build, and it lets you get seat height down lower, improving your CoG for cornering.

If you'd like I'd be glad to design one for you.
 
Here ya go

Attached are two views of a basic T type drop center axle design. Since you indicated that you intend to use a reversed straight front fork for your rear wheel support, I have not drawn that in, as I'd need a bit more info before I'd do so.

A basic tadpole is as simple as it can get - as drawn it is a 48.5" long wheelbase, and a 32" width.
 

Attachments

  • Basic.jpg
    Basic.jpg
    30.6 KB · Views: 694
  • Basic T.jpg
    Basic T.jpg
    33.6 KB · Views: 593
Simon,

Wondering if you be as kind as to sketch up a front steering single wheel with two trailing rear wheels for me?

Something along the lines of a design like this...

http://www.target.com/Triton-3-Whee..._com_brand-bin&searchRank=pmrank&frombrowse=1

Thank you kindly for the work you have done so far...
Sure, but I have some advice. I have ridden a Triton Pro X, and while it corners well for a delta trike, the fact is that a direct drive single speed front wheel is a real bear to pedal.

I know from your other thread that you are contemplating an MB, running under power and seldom if ever pedaled, but I'd like to suggest that Murphy absolutely loves pranks, and having to ride one home several miles with a dead engine would get really old really fast.

Also, how do you propose to power it? What type engine, what type drive? Other considerations are - what size wheels do you want? Since on a recumbent it is the X-seam measurement that is of primary concern for seat/crank separation, how tall are you? What is your X-seam length?
 
Last edited:
Also, how do you propose to power it? What type engine, what type drive? Other considerations are - what size wheels do you want? Since on a recumbent it is the X-seam measurement that is of primary concern for seat/crank separation, how tall are you? What is your X-seam length?

Simon,

At my first ever attempt at a recumbent, I was just trying for the easiest approach at doing it. I have already built several successful types of MB's over the years.

I would consider a single wheel drive in the back to be able to make it a multispeed recumbent.

I would like to go with 26" wheels if I could. I would go with either my BMP kit or my GEBE setup powered by my EHO35.

Top speed is not my concern, I am very happy with the low 20mph range and a little extra power for pulling.

I am a tall one at 6' 2" . . . but would like to stay with a more compact, shorter wheelbase design if possible!
 
Back
Top