[Discussion] 3 Wheeled motor bike

[Doc_Brown]

I stumbled apon this beauty, and after examining it can not work out how it would work (steering mostly) unless its some sort of CV joint.

I'm curious to know from those that know bikes (and ridden one! :P ) What you think of this.

Also its potential to build in technic.

Edited December 22, 2013 by Doc_Brown

[Moz]

It looks as though the middle wheel is on a trailing arm that can move out of line a little. Or possibly the two front wheels are on a pivoting bogie. Remember that motorbikes don't usually steer much, they lean. And a display bike like this doesn't have to ride well, it just has to be rideable at all.

I'd be more concerned about driving up ramps and kerbs, where it would be easy to unweight the middle wheel just as you want to apply power. Trucks get stuck like this occasionally, where a 6x2 truck going up a ramp will have to hit the start quite fast to avoid having the driven wheels in the gutter while the weight is on the outside wheels. Or go up at an angle, but that's not always possible.

Edited December 22, 2013 by Moz

[dhc6twinotter]

Pretty cool looking bike! The steering pivot is in the center of the hub, and the rim is shaped like a donut to fit round the hub. The grey steering linkage you see in the picture acts like a push/pull rod which appears to be connected to some kind of steering box or other linkages beneath the fuel tank. I'm not sure how the steering gets connected from the handle bars to the gearbox, but I assume there's a few more linkages under the fuel tank. Also, according to the article I've posted below, the rear wheel also steers, but it is not connected to the handle bars. It's a self-steering wheel and relies on a dampener to keep it centered.

This would be neat to build out of LEGO, but I'm not sure how you would go about building the front and rear hubs. You would not be able to use a regular LEGO rim inside the tires. Off the top of my head, the only thing that I think may work would be to use a couple of large turntables for the rims/hubs and figure out how to mount a tire around the turntables.

I don't ride bikes, nor do I know much about their handling characteristics. However, I see several major flaws with the design. First, there is no suspension on either the front or mid axles. Both axles do have pivot points for the swing arms, but no springs. Second, the engine is placed backwards with the transmission in front. The power is now going the wrong way, which would essentially give multiple reverse gears and one, slower forward gear. The article I posted below says, "with the engine reversed, the drive sprocket is itself driven by a belt and pulley, to get the correct drive direction back." I think most of the people here in the Technic section know that adding a belt to something doesn't reverse the direction. The bike would need a couple gears meshing together instead.

If I were to buy a bike with a pushrod type steering like that, I would would want some form of redundancy. A single linkage connecting the front wheel to the handlebars offers no redundancy. If the linkage, the knuckle, or whatever else under the fuel tank fails, I'd be dead. If that bike were to ever make it to production (doubtful), it would need steering linkages on both sides.

The guy who designed it looks like a great designer, and knows enough about engineering to make a compelling design. There are some pretty major engineering flaws though.

I found an article about the bike:

http://www.motorcycl...etter-than-two/

That sure would be a cool Technic project though!

Edited December 22, 2013 by dhc6twinotter

[Zerobricks]

I'm not very impressed...

[Gee]

But can it wheelie?!

[Doc_Brown]

Thanks for your feedback guys.

I just have this feeling that something isn't right. Even if the front and the rear wheel pivot in the center, when it turns some part of the tire would have to skid on the ground.

But can it wheelie?!

I don't think it can actually! haha.

[johnboy]

What is the advantage of this design?

[Milan]

What is the advantage of this design?

50% more contact with the road.

[D3K]

If only the middle wheel is driven, you could also, with as powerful motor, have ridiculous acceleration compared to normal bikes I would assume.. As you don't have to worry about flipping it/do a wheelie

[johnboy]

50% more contact with the road.

Do you ride a bike? A quad has 4 wheels, try getting one around a corner at the same speed as a two wheeler.

This 3 wheeler would be very difficult to tip into a corner, and when you did the push (under steer) would be quite difficult to manage.

[Milan]

Do you ride a bike?

Yes, pretty much all the time.

A quad has 4 wheels, try getting one around a corner at the same speed as a two wheeler.

Why would you compare quad with this bike?

This 3 wheeler would be very difficult to tip into a corner, and when you did the push (under steer) would be quite difficult to manage.

Maybe, maybe not, we never drove it.

[Saberwing40k]

Looking at this thing, I see no way for it to be rideable in anything but a straight line. Or at all, for that matter. I mean, look at where the chain and foot pegs are. You could not convince me to ride this thing.

Also, some 3 wheelers can corner harder than standard motorbikes.

[darsedz]

interesting project, even not a real at this moment...

...

This would be neat to build out of LEGO, but I'm not sure how you would go about building the front and rear hubs. You would not be able to use a regular LEGO rim inside the tires. Off the top of my head, the only thing that I think may work would be to use a couple of large turntables for the rims/hubs and figure out how to mount a tire around the turntables.

...

maybe somethink like that, with small rubber dampers - to add a little flexibility into wheels?

Edited December 22, 2013 by darsedz

[Doc_Brown]

I would like to give it a go, but as dhc6twinotter said, the steering pivot is in the center of the hub. :/

I just have this feeling that I would be impossible in RL, haha.