FWD MBB delta trike

Vargas

Well-Known Member
I have been thinking on building a FWD MBB delta trike.
Has anyone tried it? Any ideas, concerns or suggestions?
 

Vargas

Well-Known Member
It is a Cruzbike

FWD means Front Wheel Drive; MBB means Moving Bottom Bracket, what for short means a Cruzbike.

A delta trike is a trike with a single front wheel, in opposition to a tadpole trike which has two wheels in the front.

Thus a FWD MBB delta trike is a Cruzbike with two rear wheels...
 

Kim Tolhurst

Well-Known Member
tippy

Hi. I have built a trike in the configuration you are suggesting actually using a CB Quest V1 20. to find it very tippy, too tippy. Power and steering causes the inside rear wheel of direction of turn to lift. Project disbanded. Remember trikes, front wheel drive when we were young?

Who will fix the tippy?

Kim.
 

will_rifkin

New Member
tried it, am looking for a simple leaning mechanism

i009899,

A tall, 3-wheeled recumbent needs a means for leaning. Those mechanisms tend to be complicated, according to my searching on the web.

I tried bolting one 26-inch wheel by one end in each rear dropout just to test the principal. The bike was almost unrideable on a street with a sideways slope or crown in it. Plus, it had no rear brakes.

The people at the Dutch company, Raptobike, seem to have come up with a mechanism for leaning that slots into the rear dropouts. See http://www.raptobike.nl/blog/raptotrike/. There are a couple of still photos and a video.

There have been a number of frames for putting dual rear wheels on a road bike. The wheels are fairly far apart, and the rider still sits on top of a regular road bike seat, which enables leaning. An issue with a recumbent is that the rider has a restricted ability to lean to compensate for a cambered road. One option is to put the recumbent's seat on a flexible or pivoting base so that the rider can lean.

Putting a pivot point for the frame on a piece in the rear dropout is clever. The twin rear wheels can then follow the angle of the road, but the rider can keep the main part of the frame upright and balanced.

Some mechanisms that with such pivots employ a section of a disk brake with its caliper to enable locking the lean angle when one is stopped.

Hope that gives useful insight. Best of luck with your experimentation. There must be a simple way to do it.


Will

 

Vargas

Well-Known Member
I gave up

After some search I found it had to lean and gave up. Too much work for something I would not be sure about the final result. And probably a bad riding experience in the end.
anyway thanks for your ideas Will.
BRs,
Vargas
 

Eric Winn

Zen MBB Master
Tim Hicks Scratch-Built Tilting Trike

Tim Hicks has a lengthy write up of his scratch-built Black Max tilting trike showing his tilting design with several close-up pictures at http://fleettrikes.com/blackmax.htm

Arnold of RaptoBike seems to be using similar but more refined and compact geometry in his RaptoTrike concept and I get the impression it is intended to be reversible, e.g. perhaps convert to tilting rear for winter and then back to single for summer. The tilting looks like fun though so I wonder if people would ever convert back...

There is a still from the RaptoTrike video starting at 0:31 that provides a better view.

http://youtu.be/GEOGr3oy3H4?hd=1&t=31s





-Eric
 

Charles.Plager

Recumbent Quant
Here's a link to a french

Here's a link to a french forum that talks about a moquito velomobile. It is a FWD trike (although it is not a MBB because the steering/leaning is done with the rear wheels). Quite cool. :D

XGR10BarSteering-small.gif height: 285px;


4barslinkage.gif height: 380px;

 

John Tolhurst

Zen MBB Master
Oh, the old

Oh, the old steering-is-proportional-to-lean assumption.

At high speed, a little steering give you a lot of sideways force and ... oops ... you don't have enough lean to compensate ..... ah!!! HIGH SIDE LAUNCH!!!
 

Eric Winn

Zen MBB Master
With the way they are

With the way they are constructing the body, perhaps they intend to add wings...

It is cool looking, though...

-Eric
 

Shakey

Member
Offset Rear wheels?

I just stumbled across this thread & recently I have just been looking at something that might fit.
One thought, FWD could also mean Python.
Here is a simple but a little unothodox solution for a tilting FWD trike. Once you get past the idea that the rear wheel have to be across from each other, it is pretty interesting idea.


 

will_rifkin

New Member
worth doing the same on a Cruzbike

Thanks, Shakey, for identifying that iLean approach. I had just thought up the same thing and experimented on some flimsy components.

I have installed a bottom bracket in my conversion bike where the old bottom bracket used to go. Now, I need to find a crankset on which to mount the 'outrigger' wheels. The additional wheels could be a full 26 inches in diameter, with the crank arms 180 degrees apart or smaller wheels (about 18 inches) with the crank arms 90 degrees apart.

I can try it first with the current rear wheel in place, and then I can remove the rear wheel. The crank arms should be plenty strong enough to take the loads.

If I leave the front chainwheel in place on this extra crank, then I can use that as a locking mechanism when I come to a stop. I can mount a front derailleur lower than normal, to a point where it interferes with the sprocket teeth when the derailleur is in the down position. That will prevent the chainwheel from rotating, which prevents the crank arms from shifting up or down, meaning that the bike will not be able to lean side to side.

Plan B is to use drum or disk brakes on the outrigger wheels. When at a stop, the bike can lean only if the outrigger wheels roll slightly forward or back (though I will have to test this one in practice).

What makes it all so easy to do is that the Cruzbike has an empty spot for mounting the bottom bracket. I have spent the last year trying to figure out how to take advantage of this heavy-duty pivot point ...
 

kidneyboy

Well-Known Member
http://i561.photobucket.[/b]

[IMG][IMG]http://i561.photobucket.com/albums/ss51/kidneyboy1/047.jpg[/IMG]

047.jpg



This is a bolt on tilting rear end that Dennis Grelk ( I think) uses on his lowracer.
 

kidneyboy

Well-Known Member
Obviously I still haven't

Obviously I still haven't figured out how to post a pic from my photobucket site.
 

Eric Winn

Zen MBB Master
Let me try. I usually just

Let me try. I usually just upload a pic.

Here is an embedded link:

alt="Bolt-on tilting rear end"
047.jpg








































Done this way:

ForumLinkToExternalImage.png width: 770px; height: 521px;


-Eric
 

Mark Amey_2

New Member
There is no shortage of

There is no shortage of leaning trikes:

http://www.tripod-bikes.com/?lang=2

or this:

http://www.mjmmobile.com/

OK, the latter doesn't lean, it's just fun.

Velocologne do a leaning FWD MBB trike which leans by eing disarticulated in the middle of the frame.
 

jmp23834

New Member
Universal Joint

I am considering building a FWD MBB Delta Trike and found this thread interesting. I was wondering if something like a universal joint where the main tube meets the rear axle would work instead of tilting wheels. If side to side swivel is all that's needed could you use a head tube on the back. I don't know if either of these would work but got the idea seeing a car pull a trailer. The trailer tracked fine with no tilt.

Any thoughts would be appreciated.
 
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