I always thought this was pretty cool.

[deorman]

from http://www.bikeexif.com/ Thoughts?

 

[XC204]

That front end begs to be copied on a burito. That might make them a little more stable for us old guys. Are you listening Highridah!

 

[Chainsaw]

It wouldn't be hard to duplicate, as it's very similar in desgn to a couple of the Atomic Zombie bike plans. Just a little imagination and some trial and error. Ride would be real close to that of a recumbent.

Seeings how there would be no gas tank or engine, you could slam the seat as low as you'd like and get the pedaling out front, maybe even do the front wheel drive thing instead of rear wheel drive.

Lots of cool possibilities! I love the looks of bikes that sit lower than their tires!

 

[DougC]

It wouldn't be hard to duplicate, as it's very similar in desgn to a couple of the Atomic Zombie bike plans. Just a little imagination and some trial and error. Ride would be real close to that of a recumbent.

Seeings how there would be no gas tank or engine, you could slam the seat as low as you'd like and get the pedaling out front, maybe even do the front wheel drive thing instead of rear wheel drive.

Lots of cool possibilities! I love the looks of bikes that sit lower than their tires!

The Atomic Zombie ones I recall all had single-sided steering, not "true" center-hub steering.

Single-sided steering is easier to build for bicycles/motorcycles than center-hub is, because with a single-sided front end you can use a regular front hub and simply adjust all the extra axle length to stick out of one side only and mount the pivot there. The pivot axis of the front wheel doesn't need to be exactly centered, if it is just close it will still work okay. Not great, but the machine will be rideable.

A lot of bicycles and motorcycles have been built this way by home-builders over the years. The oldest photo of an example I have found online is below (I don't recall the source).

The above example is probably taken before WW-1, since the tires appear to be white rubber and those kinds of tires were unavailable completely during WW-1, and were rare and expensive after that. Also, the single-cylinder motorcycle engine matches the types at that time, since by 1920-1925 most motorcycle companies switched to using V-twin engines.

-------

The Ner-A-Car had true center-hub steering, the front wheel's pivot point is located exactly on the wheel's centerline. Also the Ner-A-Car's front wheel appears to be supported from both sides.
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[icyuod2]

its funny how some things seem to come around full circle.
viewtopic.php?f=11&t=28214&st=0&sk=t&sd=a&hilit=stretching

 

[Chainsaw]

Yeah Doug, I realized the difference in the steering, I was just using A.Z. in that the bikes are similar in looks and would be a good basis for starting a build. From that point on the builder would have to figure out the steering and how it would work into his build. Anyone who would attempt building a bicycle version of the NerACar would probably have enough skills to figure the steering out.

I have seen this type of steering on a few customs and have always wondered how they handled. I've never seen any being ridden. Any views on how it would handle at the slower speeds of a bicycle.I've always thought the steering would be sluggish.

 

[DougC]

With a single-sided steering setup for a bicycle/motorcycle, the steering kingpin axis is tilted towards the tire's contact patch. The tire's alignment doesn't stay vertical when it is turned hard, but the contact patch still stays roughly centered.

----------

(Also We Note: the terms "center-hub-steering" and "hub-center-steering" seem to get used interchangeably to describe these things)

A cutaway diagram is shown here (DiFazio type). Most others are variations of this general layout.
http://www.tonyfoale.com/Articles/Steer/STEER.htm

The bearings you need for this are called "thin-section" bearings.

There are,,,,, relatively,,,,, cheap ones available:
Here's a 3-inch ID for $50: http://www.vxb.com/page/bearings/PROD/Kit9494
A 4-inch ID for $90: http://www.vxb.com/page/bearings/PROD/Kit11878

I can't recall seeing any center-hub-steer bicycles, but it would surprise me if it's not ever been done.
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[Chainsaw]

I wanna say that there was one or two on BR&k a few years back, it was either on there or it could have been on CBN. I'm pretty sure one of them was from Europe, possibly the Netherlands or Germany. All I remember is that there was quite a stir.

Thank you very much for the explanation and link. I've kind of got the gist of what you and they are talking about. I'm gonna read it a few times, see how things settled in my "brain pond" and will probbably ask a few more questions. I'm not up on all them fangdandled things but if there's something I like and am interested in , I try to find out more about it. You've sparked that interest. :wink:

 

[DougC]

I wanna say that there was one or two on BR&k a few years back, it was either on there or it could have been on CBN. I'm pretty sure one of them was from Europe, possibly the Netherlands or Germany. All I remember is that there was quite a stir.

There was this one not too long ago.
http://www.bike-trend.com/forkless-bike ... a-bicycle/

I also saw a custom motorcycle (it won some championship in Europe somewhere) that looked very, very close to that vintage motorcycle I posted.
Okay, took me a couple minutes:
http://www.dieselpunks.org/profiles/blo ... candinavia

The video shows that the front end is pretty flexy, but it is a show-piece so that's not surprising.
http://www.youtube.com/watch?v=tRY12kFZ ... _embedded#!
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[Chainsaw]

Yep I'm familiar with Olli's bike. I've known of him and his bikes for several years.
I also remember the motorcycle.
Olli's is similar to several other bikes that have been done. Jeff Chapp's (RIP) Time Frame is one of these bikes. It dates back to at least 2007, I'm thinking 06 or 05. I have ridden Jeff's bike and it rides smooth and precise.
http://img123.imageshack.us/img123/9344 ... 5ctuq9.jpg

Jeff passed away this summer but his bikes will live forever. If you'd like to see his last creation, then check out the newest issue of Bike, Rod and Kustom. His last bike had articulated steering!

None of these bikes represent the NeraCar steering style though. After this weekend I'll have a little more time and I'll try to hunt down the bikes that specifically used this style. I know they're out there somewhere.
Have a great weekend,
Chainsaw

 

[DougC]

One problem that occurs to me is that it would be difficult to get the usual front-wheel steering geometry.

A normal bicycle has a rake of maybe 72º and a trail of about 2.25 inches. With a center-hub-steering wheel, the steering axis needs to be contained entirely within the diameter of the front wheel bearings....

By a quick CAD estimation,,,,, assuming you could get a useful front pivot that was only about 3" tall and an inch in diameter (which is a bit cramped) that would still mean that you would need to use wheel bearings that were somewhere around 6.25 inches in diameter. Those would not be cheap, even from China.


If you didn't need it to be extremely durable, you have other options,,, such as using brass bushings instead of actual ball bearings. You'd still need the machine tools to do it tho', I can't see this being a Dremel project.

~

 

[icyuod2]

theres more than one way to skin a dead cat.
i think the method i used for skull-o-sis could be adapted to work.

follow me here.

threadless headset
custom clamp top and bottom which allows you to attach a wheel mounting plate beside the head tube. (right or left side)
attach a trike wheel to the plate.
offset the head tube to center the wheel on the bike, (i'm assuming this is a completely custom build) and do the steering similar to skull-o-sis.

with the loss of forks, steering dambing probably won't be required.
that being said, the further out from the head tube the better when it comes to attaching you steering linkage. (opposite side to the wheel)

 

[Chainsaw]

Doug, the one thing to remember is that this whole "steering style" talk is about adopting the NeraCar steering to a bicycle. Not a "motorized something" but a custom bicycle. The speeds would be lucky to reach 17 miles an hour, so alot could be done for very little or no cost.

I'm not gonna claim to know all the stuff you are talking about but I fully believe that the advice and info you've given is 100% correct. Anyone entertaining the idea of building a "motorized something" should definitely take your advice and run with it.

But again, this is referring to a bicycle application. You'd be surprised how many of the RRB and FBN guys could easily take this steering idea and build up a complete bike that is fully rideable with little to no steering disadvantages.

Like ICYOUD2 suggested, some slight modification of his Skull-o-sis would definitely be a good starting point.

Once I get my Autorama bike finished, I will think about a possible build using this type of steering.

Until someone actually builds and rides a bike with this application ..... everything is just words and drawings. You've given all of us some insight to what may need to be done to get this contraption peddling down the street!
Thanks!
Chainsaw

 

[DougC]

Doug, the one thing to remember is that this whole "steering style" talk is about adopting the NeraCar steering to a bicycle. Not a "motorized something" but a custom bicycle. The speeds would be lucky to reach 17 miles an hour, so alot could be done for very little or no cost.

I would bet the Neracar didn't go much faster than that either... ? from what I've seen online I'd guess 30, 35 mph? The Neracar used a unique constantly-variable transmission, based on a friction-drive setup.

But again, this is referring to a bicycle application. You'd be surprised how many of the RRB and FBN guys could easily take this steering idea and build up a complete bike that is fully rideable with little to no steering disadvantages. Like ICYOUD2 suggested, some slight modification of his Skull-o-sis would definitely be a good starting point.

It could look similar, but it wouldn't be center-hub steering.

I also always note when a "proposed" steering setup is potentially a bad idea--that is, one that doesn't provide stability by using anything near the normal amounts of rake & trail. Vehicles built with oddball steering systems can be entirely usable at low speeds but tend to suddenly become unstable at high speeds--which could be only as fast as coasting down a bumpy hill at ~25 mph or so. Anyone getting on one needs to know that before they find out on their own, the hard way.

Until someone actually builds and rides a bike with this application ..... everything is just words and drawings. You've given all of us some insight to what may need to be done to get this contraption peddling down the street!

I think I could make one and it sounds interesting to try to do, but I don't really want it myself.

If I sold one just for the cost of the bearings & metal, the 3" might be ~$150 and the 4" might be ~$275. The 3" might need to use bronze bushings for the steering axis, since I don't know if there's enough room to fit ball bearings in there. The 4" should be able to fit regular headset bearings for the steering axis. The thin-section bearings are expensive, no doubt--but I think in this use they would last a very long time, basically forever.

There would be no easy way to add any kind of front brake.
And even at that--the steering rake could be adjustable but would have basically no trail at all, so it still might feel odd at times.
~

 

[DougC]

I've been looking for a while now and I cannot find one single example of a hub-center steer bicycle online at all.
Can it be that there are none? :shock:
I can find about a dozen models of motorcycles.

For the sake of clarification:

Monoforks don't count. A monofork is a single-bladed fork that uses a special hub.
One commercially-made example is the Cannondale Lefty. http://www.google.com/images?hl=en&q=ca ... 12&bih=937

Knuckle-joint steering doesn't count for this either.
A knuckle-joint front end is like what the forkless bike of Olli Erkkila has: http://www.bike-trend.com/forkless-bike ... a-bicycle/
Note that the axle of this steering type (the axle that the front wheel rotates on) turns left-and-right with the front wheel, as the front wheel is turned. The Yamaha GTS1000 is also an example of this although one of the steering axis pivots is placed outside & above the front wheel. Knuckle-joint steering ALWAYS only supports the wheel from one side, since there's no way to support the wheel's axle from both sides when the wheel's axle pivots with the wheel.

A hub-center steering setup has an axle that does not turn left-and-right, and a separate bearing carrier on that axle that does.
It is possible to make them with support on only one side, but usually they have supports on both sides, since the stationary axle allows it. The Neracar did it, and the Bimota Tesi 3D is one of the prime modern examples. This page shows left- and right-side photos: http://www.webbikeworld.com/bimota/tesi-3d/

Can you find any bicycles like this?.....
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[deorman]

Finally found a good view of the steering, here: http://www.bikeexif.com/1921-ner-a-car

Also

 

[DougC]

Any pics of what's inside would be interesting... there's not a lot of room in there.

What I am planning would not be identical, but would be true hub-center steering.

 

[garagegoon]

That thing is awsome... gotta build a bike that resembles it....

 

[DougC]

There's a link on the bikeexif page to this nice one:

http://thevintagent.blogspot.com/2009/0 ... c-new.html

A bit too much bodywork for a pedal-bicycle perhaps, but would be nifty for a scooter/moped mod.
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[DougC]

Looks like with the 3" ID bearings (the $50 ones) it will have 50º of steering range, side-to-side. Could maybe squeeze that to 55º or so. Not a lot, but usable.

None of the {modern} motorcycle setups has much range either.
~