No-Fork project, bicycle geometry hacked

Interesting! Thanks for the explanation.

So if I understand correct a rider has 15° +ve on the straights at whatever speed, and 15° -ve at high speed in the bends. Making the normal neutral (stable at 0°) bike most suitable for the track. Must be that tracks have been designed for normal bikes :-)

Do you, or anyone else, know if it has ever been tried to make a, lets say a 10° neutral bike?

On the straight, you have camber steer towards the outside of the track. In the corners, this continues until you pass the 'neutral speed' at which the wheels are normal to the surface, after which you start to have camber steer towards the inside of the track. The neutral speed varies with position on the track (radius) and between tracks, but is typically about 50km/h on the black line. Using a sign convention of +ve being towards the outside, track cyclists can ride at different points on the track at angles from about +35° (riding slowly round the top in the middle of the bends) to -15° (going round the corners well above the neutral speed), for a bicycle which is neutral at a camber of 0°

If you built a bike which was neutral at +15°, it would have to work at +20° to -30° relative to it's neutral camber point, which doesn't seem impossible. However, you're creating a solution to a problem which doesn't exist, since a conventional bicycle with the wheels in the plane of the frame already copes perfectly well with these conditions.

Is this the reason track bikes have such a massive trail and less fork-rake?

Is this the reason track bikes have such a massive trail and less fork-rake?

Two explanations are offered, firstly by people who don't understand geometry who say smaller fork offset gives the faster steering needed on the track, and secondly by people who do understand who say that more trail gives the extra stability needed on the track. Since it's barely noticeable when you switch from a 30mm offset track fork to a 40mm offset road fork on the same frame, I suspect the true reason for short offset forks on track bikes is that they came into favour in the 1970s when track bikes often had much steeper angles than now (75° or even 76° head angles were not uncommon) and nobody has seen any reason to go back. Look put a 43mm fork on all their track frames from 71.5° (small 596) to 73.5° (large 464), and 34mm or 40mm on the 496 Piste with its 74.5° head angle, so you can see that track bikes work just fine with quite a range of trail, from 50mm to 68mm in the case of the Look range.

^ that would make it more like a fashion thing then....

Do you, or anyone else, know if it has ever been tried to make a, lets say a 10° neutral bike?

Any thoughts on this?

So, when are you two getting married?

Any thoughts on this?

Camber steer is something few bicycle makers give any thought to, since its effect is tiny compared with the other steering effects. For most purposes, it can be completely ignored, and often is. A normal road bike doesn't seem to have any problems with camber of up to 40°, after which grip is the problem anyway. The only reason we're discussing it at all is that you have deliberately created the first bike which suffers from camber steer in a straight line on a level surface!

So, when are you two getting married?

we were alright until you mentioned this^

http://vimeo.com/33539880

this shows enough init, not getting into the "advantages" discussion again. My bike, the No-Fork, has no, non, geen and niente advantages whatsoever. It is silly, stupid, and a useless waist of money. Just a way to pass my time. Hope thats clear now.

Seriously, I wasnt really going on about anything with my bike.
My questions was "Do you, or anyone else, know if it has ever been tried to make a, lets say a 10° neutral bike?"

My questions was "Do you, or anyone else, know if it has ever been tried to make a, lets say a 10° neutral bike?"

And my answer was that nobody has tried because there are no circumstances in which it would be useful. It could only be done for one side, and as we have seen even track bikes experience camber in both directions.

OK, I didnt quite get that.
Just thought that with speeds increasing all the time, the -ve camber steer has grown over time. Someone might have tried something... presumably the velodrome design has adopted?

Wall of Death bike ?

and chain slack
just getting rid of gravitational disturbances...

Just thought that with speeds increasing all the time, the -ve camber steer has grown over time. Someone might have tried something... presumably the velodrome design has adopted?

Camber has been +/-40° on the road for years, remember Jobst showing us that slicks were the way to go back in the 70s

Unless you stop mid corner on the track, camber at the velodrome is always less than this. Maximum speeds at the velodrome haven't actually gone up a huge amount - the flying 200m was done in <12s at the 1948 Olympics, the world record is now 9.572. That probably means that total lean angle (banking + camber) has changed by 10° in 60 years.

Again, camber steer is only a problem if you make it one. For over a century, people have placed the wheel axles at right angles to the plane of the bicycle and not had to worry about it.

Ah, but this is completely different ballgame. Here^ the cambersteer is getting Jobst round the corner... sure its not a problem!

We was talking straight line stability wernt we. The veldrome is also a way to approach a straight line while going round in circles. Otherwise it would be flat wouldnt it.

It could have been that there has been an idiot like myself to try and create a 10° neutral bike for whatever reason...

But I wil take a no as an answer to my question. I think it hasnt been done cause no one knows how to... I was just wondering.

My objective creating the No-Fork has been just creating a simple fork...

http://vimeo.com/32841274

Oh, and me bike has no camber steer, just camber wheels.

Oh, and me bike has no camber steer, just camber wheels.

We're still waiting to see the patent where you explain how this is achieved.

we were alright until you mentioned this^

You're made for one another.

So basically, you did it because it looks cool?

Hipster.

^^^I'm guessing offset trail, but presumably the clever bit is how you calculate the offset required?

We're still waiting to see the patent where you explain how this is achieved.

Watch video, come over to see/convince for yourself like others did. Or read on...

http://vimeo.com/33539880

You're made for one another.

no

So basically, you did it because it looks cool?

Hipster.

OK ok ok! I will put the whole story together. I'll start digging up the pictures then.

Before 2004 Ive been building all kinds of bicycles. Besides cars my interest grows in the Flevobike. A very neat and usable concept in my view. It is possible to ride the bike handsfree in almost all situations, even from the stationary. I build a few nice ones that were stolen from my workshop then. After the Flevobike my interest shifted to rear wheel steering. The front wheel drive of the flevobike is fine, but there is always a hint of pedal power in the steering. The short chain is very attractive though for a recumbent. The rear wheel steering really got me and I kid myself with the idea that we have accomplished a great deal in that. There may have been about 10-15 bikes, and in the end both me and my dad were able to ride them quite comfortably. And stable, even at higher speed. I dont remember how and when I saw my first cardan drive bike. It may have been the Kopenhagen, Im not sure. It made an enormous impression on me and I couldnt resist getting it into one of my bikes. The first one I made was this one:

but I wasnt quite satisfied with it. So I made this:

There's no pictures when it was finished, but it was one of the best builds I ever did, a true dream to ride! Hell, I still cant forgive myself for breaking it to pieces! Dont ask me why, but it was replaced with this:

Boy was I glad when the grinder made an end to it. I decided I was going for simplicity, and that wasnt it! So i made this one:

It was Ok, although frustrations with the carbon ridged single side half-fork in the front was really the start of the NF. The alu crown piece just didnt work out right...something had to be done about it...
to be continued...

^^^I'm guessing offset trail, but presumably the clever bit is how you calculate the offset required?

Clever!

No Fork, am I right in assuming that you are based in or near Amsterdam?

Wow, suddenly I'm impressed. You have been making some interesting bikes...

No Fork, since you've made all these wonderful bicycles with driveshafts, why didn't you incorporate a driveshaft in the no-fork bike? Surely, as has been pointed out previously, it would be more desirable than a chain drive with the axle angles involved??

on single chain stay it may end bad.

See all current BMW shaft drive motorbikes for an explanation of why you don't have a clue

Does the rear cog lie at the same angle as the wheel? Ie does the chain just have a bit of twist in it, or is there some, more complicated way of tranferring drive fom an upright cog to a cambered wheel?

At the moment, he has a twist in the chain, that's why we're discussing more complicated ways of transmitting power from a horizontal crankshaft to an inclined wheel. Shaft drive would work, as would some kind of CV joint, and there might be other feasible schemes.