speed wobble

[Johan Bornman]

Hi Johan

 

I think you need to study Newtons laws again and then reread my comments as well as your comments about my comments. You may just find yourself a little embarrassed.

 

Instead of suggesting that I read this or that, why not drill down to specifics. Here are Newton's three laws, compliments of Wikipedia.

 

Which one are you referring to?

A physical body will remain at rest, or continue to move at a constant velocity, unless an unbalanced net force acts upon it.

The net force on a body is equal to its mass multiplied by its acceleration.

For every action there is an equal and opposite reaction.

Don't allude, explain.

 

I'm not blushing yet.

 

[Johan Bornman]

 Cut cut cut.

Certainally at higher speeds' date=' I would expect the "friction" on the front tyre to decrease, not increase, unless of course the rider is stiffenig up and putting all his weight on his arms and thus the front wheel. This supports your contention of rider involvement.[/quote']

 

On a modern road bicycle with tyres pumped to any reasonable pressure there is no friction between road and tyre. Friction implies sliding and there is none. On a car tyre there is friction from the tyre pinching the road as it's shape changes as it rolls over the surface. This is evident from the squeaking noise a tyre makes when riding slowly through a parking lot with a smooth floor. That's from road pinch.

 

A bicycle tyre doesn't do that and rolls perfectly. Again, we know this because a front tyre lasts very, very long, especially if you don't brake much by riding on flat roads. The only wear is from braking.

 

A bicycle tyre does however, have rolling resistance, this is from hysterisis in the rubber (energy losses due to imperfect rebound) but has nothing to do with friction.

 

 

In my motorcycling case' date=' we firstly found that the idiots who assembeled the bike had not tightened up the steering head, and that was pretty loose. That partly sorted out the problem. Next we fitted a brace between the two sides of the fork, matters improved further, but the "hint" of a potential wobble was still there all be it mild. It was one of the SA motorcycle circuit racers who raised the tyre issue. He went into a long and detailed explanation of tread patterns, direction of rotation, irregularities in the tread pattern etc.

We fitted a new tyre, and no more wobble!!!!!

Yes I also agree items carried on the bike which can affect the balnce of the rider, and centre of gravity can also play a role.

 

 

[/quote']

 

I don't believe the expert's story about tread pattern, direction of rotation and all that. That implies a faulty tyre. Had that tyre been fitted to another motorcycle, it would have proven that the tyre was not at fault. However, what had changed was the mass and dimension of the tyre and that influenced the harmonic. It's a little bit like a finger on a guitar string, it messes up the tune.

 

Finally, centre of gravity doesn't come to play in wobbles. The wave is entirely in the plane of the bicycle and the little bit you can change the CoG makes no difference. What you want to do is remove the node. That's done by standing up.

I understand why you wouldn't want to try that on your motorcycle at 180 kph, so I suggest staying at 120kph or below, which should do the trick.

 

Johan Bornman2008-02-22 00:25:34

[The_Break]

Hi Johan

 

Newtons 3rd Law of motion. If you do draw a force diagram of all the external forces acting on the bike you will see what I mean. Also, if you knew your friction equations you would know that there are 2 types of friction, static and dynamic friction. We use static here.

 

What's more draw your moment diagrams and then you can integrate using this information and you should come up with a stress equation which will tell you that the fork indeed flexes backward and your wheelbase shortens. As mentioned in one of the replies as well. Then if you take a look a stability equations and vibration and harmonics you may just understand. But I sure hope you know your 12 Maxwell equations cause without them you may never understand.

 

I could explain all the theory, but it seems you are the oricle of science on this site so I will leave it up to you to explain what I mean to everyone. What do you guys say???? Should we make him explain???

 

And I sure hope you have more than matric science cause you are going to need it if you go around acting like you know everything and then at the same time insult people in flame suits who are wearing them because they spent 5 years studying the same stuff they are hulicinating about and got them at their graduation ceremony. Luckily my current space suit is a new version. I got it after many years of service in the design industry and boy you should she the kind of heat it held up to during all the project we put out into society across the globe. However, I could be wrong about what I know, and if I am and if that is what our countries engineers are learning at University then I sure hope they get the curriculum sorted out.

[Johan Bornman]

Hi Johan

 

Newtons 3rd Law of motion. If you do draw a force diagram of all the external forces acting on the bike you will see what I mean. Also' date=' if you knew your friction equations you would know that there are 2 types of friction, static and dynamic friction. We use static here.

[/quote']

 

Even with a force diagram, I don't see anything resembling your theory. Explain. The onus of proof of your theory is on you, not me.

 

No need to flaunt the friction equasions, just definitions. You are confusing traction issues with rolling resistance. Friction in any form plays no part in a speed wobble.

 

What's more draw your moment diagrams and then you can integrate using this information and you should come up with a stress equation which will tell you that the fork indeed flexes backward and your wheelbase shortens.

No need to swing the big spanner. Integration is a silly substitute for watching the fork flex forwards and backward. However' date=' that has nothing to do with wobbles. You haven't explained how a shortening wheelbase induces a wobble.

 

 

As mentioned in one of the replies as well. Then if you take a look a stability equations and vibration and harmonics you may just understand. But I sure hope you know your 12 Maxwell equations cause without them you may never understand.

 

Really?

 

 

I could explain all the theory' date=' but it seems you are the oricle of science on this site so I will leave it up to you to explain what I mean to everyone. What do you guys say???? Should we make him explain???

[/quote']

 

You mean "oracle". Does that make me the oracle of literature as well?

 

 

And I sure hope you have more than matric science cause you are going to need it if you go around acting like you know everything and then at the same time insult people in flame suits who are wearing them because they spent 5 years studying the same stuff they are hulicinating about and got them at their graduation ceremony.

 

 

Is it credentials I see being thrown at me? Yes' date=' looks just like it. I suggest you stop touting credentials and explain your theory. And please don't suggest it is too difficult for us to understand. Richard Feinman said if you can't explain something in plain English, you probably don't understand it.

 

 

 

Luckily my current space suit is a new version. I got it after many years of service in the design industry and boy you should she the kind of heat it held up to during all the project we put out into society across the globe. However, I could be wrong about what I know, and if I am and if that is what our countries engineers are learning at University then I sure hope they get the curriculum sorted out.

 

More credentials and zero explanation. Your theory is  bogus and no number of certificates will prove otherwise.

 

Finally, if you're so ballsy about your theories, why not debate under your real name? Methinks you're scared of making a fool of yourself. And please don't give me the usual BS as reason for anonymity.

 

 

 

[FlyingCheetah]

Popcorn anyone????? Lekker mudslinging debate on who is right and who is wrong.

 

In plain English of Afrikaans soos julle dit verkies:

 

Wanneer die vurk beweeg, en dit beweeg nie gelyk en ewe ver albei kante nie, dan veroorsaak dit 'n effense stuur aksie wat teenstrydig is met die rigting waarin die fiets beweeg. Die storie dat die pad geen invloed het nie is volgens my BULL! 'n ongelyk pad druk die voorwiel in 'n ander rigting wat die sentrale balans versteur. 'n Pad fiets se kontak met die pad is so min dat enige versteuring 'n effek gaan he.

 

Wiele vervorm glad nie op pad fietse nie, dis hoekom 'n voorwiel baie lank hou??? - WOW! Dit is inderdaad goeie nuus vir my. Ek is liggewig en omtrent 65% van my gewig word op die agterwiel gedra. So 35% word deur die voorwiel gedra wat dit net nog makliker maak vir 'n klippie om die voorwiel van rigting te laat verander. Wanneer die g@t van die saal gelig word, word die balans van die fiets gewysig. Eers is die gewig op die saal, dan verskuif dit na die pedale wat laer as die saal is en meer in die middel van die hele fiets is. Die gewigs verspreiding is dan baie nader aan 50% voor en agter.

 

Wanneer daar meer regop gesit word is daar meer wind weerstand, wat veroorsaak dat die spoed daal. Duidelik behoort die "wobble" dan minder te raak.

 

Lekker popcorn eet almal. Ons is nou nie almal die mo3rse wetenskaplikes soos sommiges op die forum nie, maar comonsense help darem ook.

 

Groenis

Tommie Liebenberg!

[The_Break]

Hey Johan

 

No more debating or explainations. I don't expect you to understand, it really needs a big base of maths and science to understand fully. No need for me to explain. I wouldn't tell you how to build a wheel unless I had designed the thing, it is not my area of expertise, so I don't expect you to understand what I am getting at, that is my area of expertise. Anyway, let's just call it quits and have a good laugh at our egos.

 

Luckily Wolverine's problems are long gone.

[Mudsimus]

4 pages of bs to sort out a problem that seems to never have existed.....you guys are special.

[Evan Andreou]

4 pages of bs to sort out a problem that seems to never have existed.....you guys are special.

 

Parliament should be a breeze

[FlyingCheetah]

Hi Modder, jy ook hier. Ek dink dit was dalk die teerpad en die lyn wat gery is. Selfde pad, ander lyn, en die probleem is weg....

[Battler]

A training partner of mine had the same problem every time when going down Cedar.

 

 

 

At the time he had a ridiculously short handlebar stem. He changed it for a longer one and "voila", problem gone.....

[FlyingCheetah]

A training partner of mine had the same problem every time when going down Cedar.

At the time he had a ridiculously short handlebar stem. He changed it for a longer one and "voila"' date=' problem gone.....[/quote']

 

See, Sorted without the long discussion about mathematics and space suits and Newton. Just plain comonsense....

[joevan]

Wow!!!!!!!!

 

Nothing so interesting or boring as "experts" all trying to prove "scientifically" that thier theory is correct.

 

All Wolverine originally asked for was some simple advice!

 

All several people tried to do was to point out to Wolverine some areas to check based on PERSONAL EXPERIENCE not textbooks.

 

I have no need to debate this subject any further.

 

Been there, done that in the end experience will win the day!!!!!!!

 

Subject closed!!

 

Hope you and Control C enjoy your debate - you'll need to have a few beers when it's over.

[Johan Bornman]

Hey Johan

 

No more debating or explainations. I don't expect you to understand' date=' it really needs a big base of maths and science to understand fully. No need for me to explain. I wouldn't tell you how to build a wheel unless I had designed the thing, it is not my area of expertise, so I don't expect you to understand what I am getting at, that is my area of expertise. Anyway, let's just call it quits and have a good laugh at our egos.

 

Luckily Wolverine's problems are long gone.

[/quote']

 

This is the biggest cop-out of the year. Best of all, you get to save your reputation because you snipe anonymously from behind a nom de plume.

 

My prediction is that you'll disappear and reappear under another name. May I suggest you use "Clean Slate" as your next?

 

 

 

 

[Guest Big H]

Teee heeee hehee hee hee hee hee!!!!!!!!!!

[Delgado]

Hi Johan

 

I think you need to study Newtons laws again and then reread my comments as well as your comments about my comments. You may just find yourself a little embarrassed.

 

Instead of suggesting that I read this or that' date=' why not drill down to specifics. Here are Newton's three laws, compliments of Wikipedia.

 

Which one are you referring to?

A physical body will remain at rest, or continue to move at a constant velocity, unless an unbalanced net force acts upon it.

The net force on a body is equal to its mass multiplied by its acceleration.

For every action there is an equal and opposite reaction.

Don't allude, explain.

 

I'm not blushing yet.

 

[/quote'] Not wishing to get involved and slightly off topic. Academics abhor the use of Wikipedia for use in research studies. You could be failed on this!!!

[lowracer]

aag flip, is die movie so gou oor?