Speed wobble ???

[The_Break]

Here we go again....

 

We've been through this and your last theory was friction - static, I think, that caused the wheelbase to shorten.

 

 

http://www.thehubsa....armonic__st__20

 

 

How do you foresee a sidewind inducing a speed wobble?

 

Have you ever actually ridden a bike? Side winds make your front wheel turn and then the wheel comes back on its own. If it happens at the right frequency it feels like a spped wobble.

And please don't tell me you have never felt the difference between a twitchy bike (short wheel base) and a slow handling bike (longer wheel base).

[Johan Bornman]

Have you ever actually ridden a bike? Side winds make your front wheel turn and then the wheel comes back on its own. If it happens at the right frequency it feels like a spped wobble.

And please don't tell me you have never felt the difference between a twitchy bike (short wheel base) and a slow handling bike (longer wheel base).

 

I'll treat the first question as a rhetoric one.

 

Bikes, cars, motorbikes, skiers, cyclists and runners all know the effect a side-wind has on forward travel. It pushes you over into to the direction of wind travel. We counter that force by steering a bit into the wind. In cars, it is noticeable by the less-than-straight angle of the steering wheel. On motorbikes and bicycles, it is noticeable by our lean angle into the wond. We've all experienced that and it is nothing new. What I don't think anyone (other than you), experience with sidewinds is an oscillating force of the type you imagine. Only in yur imagination is this side-force a pulsating one at a frequency that interacts with the steering system on a vehicle.

 

For your scenario to be plausible the wind has to blow in pulses at a frequency in the region of 5Hz. Bloody funny wind that.

 

Further, I don't understand what a short or long-wheelbase bike has to do with this. Your first hypothesis...no, make that a theory since you already proved it in your mind, was that the static [sIC] rolling resistance cause the wheelbase to shorten and through a process that can only be explained once you're master 12 theories and a large base of mathematics, causes a speed wobble.

 

Lastly, the wheelbase of a realitic bike has jsut about nothing to do with steering response (what you call twitchy). The difference in feeling is mostly thanks to the difference in trail at the fork.

 

I say realistic bike because once the wheelbase becomes extraordinarily long, it will have an effect, but in the type of wheelbases we see on shop bikes, ziltch.

 

If you want to test that, I'll gladly make available two bikes of identical geometry, identical other than the one's extraordinary long chainstays - far in excess of any bike on the market.

 

I'm not holding my breath for you conducting such a test.

[Wyatt Earp]

What a lot of hot air.

[rvdm1]

Here we go again....

 

We've been through this and your last theory was friction - static, I think, that caused the wheelbase to shorten.

 

 

https://community.bikehub.co.za/topic/13403-speed-wobble/page__hl__harmonic__st__20

 

 

How do you foresee a sidewind inducing a speed wobble?

 

I really did enjoy reading that old thread, it was a good excuse to take a break from studying.

[ark]

ok ok.

I fitted a new tyre on Friday and........... the wobble is gone ?????

[The_Break]

ok ok.

I fitted a new tyre on Friday and........... the wobble is gone ?????

 

Front or rear? It was probably your wheel that was clamped in scew like I suggested. But would be an interesting test to put the old tyre back and see if it really was the tyre.

[ark]

Front or rear? It was probably your wheel that was clamped in scew like I suggested. But would be an interesting test to put the old tyre back and see if it really was the tyre.

Firstly, it was the front tyre I replaced.

Secondly, my wheel wasn't clamped in skew like you suggested, I remove my front wheel after every ride to fix it to my rack, not that I wouldn't notice a skew wheel, and it was wobbling everytime I rode.!!