need some input RE stability

[mrtwowheel]

I would be interested in the difference between two riders of different weights. But, to be an honest test it should be done on the same bike.

Edit, or someone could strap on 50 pounds and see if there is a difference on the same bike. I could do that, but only on a 750 Honda at this time.

Edit, Just thought of this too. Next time I'm in WalMart I'm gonna pick out a cart that has the slight wobble in the front castor at walking speed. Then I'm gonna put a good load in that cart and see what happens. I could try a couple different carts too. In the old days they would pick me up and let me try on one of those shiny white jackets.

Scott

 

[Mailman]

For what it's worth, I had my wife on the back of my bike last week for the first time. I was expecting it to really affect the feel and handling of my bike , but the crazy thing is , it only felt smoother and more stable.
I was frankly impressed and pleased.

 

[mrtwowheel]

For what it's worth, I had my wife on the back of my bike last week for the first time. I was expecting it to really affect the feel and handling of my bike , but the crazy thing is , it only felt smoother and more stable.
I was frankly impressed and pleased.

I never asked a guy how much his wife weighed, so let's just not ask.

Scott

 

[Mailman]

I never asked a guy how much his wife weighed, so let's just not ask.

Scott

She's a petite flower...of course!

 

[Bob Kelly III]

I have little to say about this because I've never really had a problem with this....I have had low speed shimmy/wobble a few times
but I attributed it to the tires being in poor shape... Never had High speed wobble and I pushed every bike I have owned that was capable of it to 100mph.... the rest to as fast as it would go and didn't fly apart.... <GRIN> I cruse at 70 to 80 mph that's just my riding speed.... it feels right to me.... or at least it did .... sense I haven't Cruised on a bike in about 8 years I guess I should say USED to ! LOL
one of my bikes in the early days was bad about low speed wobble but it was a Honda 50 that was totally wore out and Loose as a goose....
and the low speed wobble on it hit at it's max speed of 45mph.... so it rarely happened because the bike struggled to go that fast.
pushing on the bars stopped the wobble every time and it rarely started on it's own even as loose as the bike was....
although My heavier bikes could go faster I never really had a wobble problem..... and don't want one !
..... Rider position is a key factor, you can tell this by just feeling how the bike corners with your butt in a different position....
so it must play a dominant roll in wobble..... pushing on the bars and leaning forward is what I do if the front end seams to be trying to wobble on me..... and it never goes beyond that ....
which is good because I hate road rash !
.....
Bob......

 

[peanut]

fcuk me you guys have some balls .

can't imagine doing a ton on my bike. I rarely go close to a ton in my Porsche when I think of all the things that can go wrong like 4x metre lengths of 2" X 4" or bricks on the highway .
i doubt I am likely to be able to generate weave on my bike because I weigh 240 lbs and I sit well back and lean back with ape bars and very little weight on the front wheel .
I was amazed at how little weight was needed to make such a difference to stability. I have never read or heard of that before nor seen any warnings on bikes to light riders .

Excellent link thanks for posting

 

[Mailman]

Ok Gary,
I'm sitting in the coffee shop after riding my bike for about ten miles, trying to induce a tank slapper. Here's my results.....Nothing

I slid all the way forward and all the way back and let go of the bars and coasted down from
25, 30, 40, 50 and 55mph.
I even kept nudging the bars trying to start it oscillating, but just snapped back straight and true. Not even a hint of wiggle.

I'm running new Michelin Pilot active tires
120/90 rear and
100/90 front
No windshield, I weigh 168lbs
So there you go. No drama when I'm on the job! Sniff!

 

[peanut]

View attachment 106584
Ok Gary,
I'm sitting in the coffee shop after riding my bike for about ten miles, trying to induce a tank slapper. Here's my results.....Nothing

I slid all the way forward and all the way back and let go of the bars and coasted down from
25, 30, 40, 50 and 55mph.
I even kept nudging the bars trying to start it oscillating, but just snapped back straight and true. Not even a hint of wiggle.

I'm running new Michelin Pilot active tires
120/90 rear and
100/90 front
No windshield, I weigh 168lbs
So there you go. No drama when I'm on the job! Sniff!
View attachment 106585

Way to go mailman.......risking your life in the pursuit of science

 

[Mailman]

Way to go mailman.......risking your life in the pursuit of science

Yeah, I never was very smart. Haha

 

[robinc]

Out cruisin back roads, tried one for the team.
Similar methodology as Bob, same results, or lack thereof.

 

[Bob Kelly III]

I have to admit a wobble at 50mph would be something to wet your pants over !
thank you guys for trying to induce one .... god I hope you don't find one though !
.....
Bob.......

 

[Ratranger]

Out of all the bikes I have ridden I have only had a headshake once. I was on a ducati 748, set on the steeper rake angle with factory damper, coming around a corner accelerating when a car pulled out without looking. I had to change my line, and the line took me over a bad section of expansion joint in the road and set the bars to shaking at about 40mph. Luckily it had the torque to just snap the throttle open and pull the front wheel off the ground ending the shake.
Even the fzr400 that was modded and had 23* of rake didn't wobble or weave.

 

[TwoManyXS1Bs]

GggGary, as subtle as your restomod changes are, have you considered getting accurate rake and trail measurements?

http://www.streetchopperweb.com/rake-and-trail#page-6

http://ffden-2.phys.uaf.edu/211_fall2010.web.dir/Conner_Hite_PHYS211_WebProject/page 2 Geometry and Construction.html

https://www.researchgate.net/figure/228363418_fig1_Fig-1-Eleven-degrees-of-freedom-motorcycle-model

 

[Bob Kelly III]

Thanks 2M !
that was a good informative read... something I have been wondering about for a long time.
seams my idea of changing the rake and trail of the forks by cutting and re welding the steering head would have been a useless venture
but... getting different Trees that would do the trick !
although I'ed probably have to make them from a block of aluminum ! LOL
.....
thank you ! ....
Bob........