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pyrocam
27th May 2005, 18:49
Hmm. I thought I could figure this out myself but instead of making up my mind I thought I might just ask.

My theory is, it pretty much doesnt matter how low the bike gets as long as the center of gravity is close to the middle of the bike
like (YAY MSPAINT)


but. im sure ive seen bikers who just stay on the same position and go around using the centrifugal force to hold them on.


Im talking about comuting corners by the way, not 180k SH22 corners. I want to practice them at 50k and whatnot.

Ive played around with putting my butt on the opposite side of the bike that im turning but it feels odd. prefer just to lift up on feet and lean that way (IE lean right while going left) to keep the bikes center of gravity pretty much upright.

anyway. how wrong am I ? Cheers

Two Smoker
27th May 2005, 18:52
VERY VERY WRONG!!!

Picture 2 is correct... ONLY DO PICTURE 2!!! Or do the opposite and drop your weight to the inside of the corner...

Waylander
27th May 2005, 18:54
I always thought that no matter what speed you lean with the bike at anything faster than walking speed and the rest of the time you turn the bars.


By walking speed I mean the point at wich you have to have your feet on the ground or you fall over.

sAsLEX
27th May 2005, 18:55
pretty much wrong

you want to get the centre of gravit low for sure, but also want it to be on the inside of the curve so its "centrifugal"force is applied to push the tires into the ground rather than pull them away will post pic later

ok pic, left is leaning with the bike slash into the corner, Centre of Gravity is red dot
right is leaning away from corner, CoG is red dot

Blue lines represent forces due to gravity and cornering in the vertical and horizontal planes respectivly.
One of the left has the resultant of these pushing the tire and bike into the ground, more grip and stabilty
one on the right is pulling the CoG down and to the rightand not pushing the bike in to the road as much
--both "bikes" heading in to the page and turning left

Coyote
27th May 2005, 18:56
Imagine leaning over like that in pic 2 when you are upright and going straight ahead. That's the sort of effect leaning like that would have around a corner

James Deuce
27th May 2005, 19:10
There's not such thing as centrifugal force. It is a centripetal force.

sAsLEX
27th May 2005, 19:13
There's not such thing as centrifugal force. It is a centripetal force.

yip thats why its qouted! but to the layman there is and most people really struggle to grasp the fact that something isn pushing them to the outside while cornering

Centripetal means centre seeking.

pyrocam
27th May 2005, 19:15
hmmm. ok by leaning into the corner. if your going fast enough, and lets say its on a curve like a track. you will be pushing the bike straight 'down' by down I mean in the direction the wheels are aligned to. but if you do pic one. then wouldnt you be putting the directional force 'down' as in towards gravity therefore putting pressure on the part of the tire in contact with the surface of the road instead of trying to push it away from where it is?

does that make sense?

pyrocam
27th May 2005, 19:17
yip thats why its qouted! but to the layman there is and most people really struggle to grasp the fact that something isn pushing them to the outside while cornering

Centripetal means centre seeking.

I would have thought it was centrufugal force since your on the 'outside' IE your acting like part of a centrifuge. oh wait.
no.
your right. my bad. centrifuge not a centrufuge my bad

James Deuce
27th May 2005, 19:22
I would have thought it was centrufugal force since your on the 'outside' IE your acting like part of a centrifuge. oh wait.
no.
your right. my bad. centrifuge not a centrufuge my bad

There isn't any such force. My 7th form Physics tutor took great pains to enforce that and had successfully challenged exam questions that contained the word centrifugal. Centripetal force describes a force being generated to prevent an object moving in a straight line. The object wants to travel at a tangent to the arc your a setting it on through other forces. A slightly more simple example than a motorcycle is a sling.

notme
27th May 2005, 19:25
http://vf750fd.com/blurbs/counter.html

One of the clearer explanations I've seen.....

The broom experiment mentioned is how centripetal forces were explained to me in a class during the collection of one of my "formal" qualifications - quite refreshing to be in a frickin' boring lecture thinking "ah shite, more particle theory - here we go again..." and instead this biker lecturer starts going on about getting your knee down! :niceone:

Will
27th May 2005, 19:27
Pyrocam,

You are going to do the Ride Right Ride safe Course, aren't you. You will learn so much there, like leaning doesn't do anything, it is all in your countersteering. And get to practise it all. :Punk:

GNR
27th May 2005, 19:35
im scared, i understand all the centralpetal forces and the rest :S, it so raa,

Waylander
27th May 2005, 19:37
Bah you people bringing physics into this. Just do what you feel comefortable with. 9 out of 10 it's correct.

FROSTY
27th May 2005, 19:39
Dude in simple terms--Stick with the bike for now.dont worry about all the knee out hanging off the bike stuff untill you've got a fair few miles under ya belt.

Skyryder
27th May 2005, 19:42
I got as far as the bvroom stick then I fell off.


Skyryder

Motu
27th May 2005, 19:49
The C of G goes through the contact patch of the tyre,a wide tyre needs the CG to shift inwards as the bike leans over,and actualy a bike with a low CG needs to be leaned over further with a wide tyre.Tony Foale has an excelent diagram and explanation in his book Motorcycle Chassis Design.

I ride a variety of bikes and use many different riding styles to get around - sometimes I move to the inside of the bike,sometimes I push the bike down and lean out.Trials riders and to some extent enduro and MX riders shift their weight to the outside of the bike in a turn....a road racer will hang off the inside of the bike,but weight the outside peg...same thing,going about it different ways.

John
27th May 2005, 19:50
As said - better than listening to us talk about gyroscopic forces and gravity enduced forces, just go do a course much less complicated and more practical (not bashing previous posts mind you! very good stuff)

ridespy
27th May 2005, 20:03
There isn't any such force. My 7th form Physics tutor took great pains to enforce that and had successfully challenged exam questions that contained the word centrifugal. Centripetal force describes a force being generated to prevent an object moving in a straight line. The object wants to travel at a tangent to the arc your a setting it on through other forces. A slightly more simple example than a motorcycle is a sling.

Well you are right and wrong, You can use the word centrifugal and in physics you can use and calculate centrifugal force in a formula, (IE Fc = mv2/r, where Fc = centrifugal force, m = mass, v = speed, and r = radius. ) but yes the force doesn't exist. Its just like the number zero it doesn't exist either but we use it every day.

An object traveling in a circle behaves as if it is experiencing an outward force. This force is known as the centrifugal force. But centrifugal force does not actually exist. Nevertheless, it appears quite real to the object being rotated. For instance, a person on a play ground round about is not experiencing any real force outward, but they must exert a force inwards to keep from flying off the merry-go-round. The person believes that they are in an inertial frame of reference, when in fact they are is not. An object traveling in a circular motion is constantly accelerating and is therefore never in an inertial frame of reference. Since the centrifugal force appears so real, but in fact it is not real, but can still be used.

So in summing up Centripetal force is a real force and Centrifugal force is perceived effect of Centripetal force.

If you don't believe me, feel free to drop steven hawkings an email and ask him :ride:

James Deuce
27th May 2005, 20:13
If you don't believe me, feel free to drop steven hawkings an email and ask him :ride:

I'd be quite happy too, and I am sure that he would agree that centrifugal force is a convenient term coined by technicians, not scientists. As for zero not existing, the zero concept was pivotal in human development. Without it very little of what we consider "modernity" is possible.

There is no such thing as centrifugal force, just as there is no such thing as "US English". Both are convenient adjectives for an inability to use a tool correctly.

justsomeguy
27th May 2005, 20:24
Just go out and ride for now and on the 19th of June it will all be explained in detail until you understand it .

sAsLEX
27th May 2005, 21:26
Well you are right and wrong, You can use the word centrifugal and in physics you can use and calculate centrifugal force in a formula, (IE Fc = mv2/r, where Fc = centrifugal force, m = mass, v = speed, and r = radius. ) but yes the force doesn't exist. Its just like the number zero it doesn't exist either but we use it every day.


yip the c in your formula stands for centripetal, not centrifugal.

look here for good info to confuse http://hyperphysics.phy-astr.gsu.edu/hbase/cf.html#cf

Ixion
27th May 2005, 21:40
In 40 odd years of riding I've never figured out the why of leaning. Always just get confused. just seem to find what works and do it. On road, lean with the bike, straight line through the rear wheel and up your legs and back. For emergencies scunch off the bike on the downside. Off road, hang off the bike the other way. Sometimes. Damn if I know when though. And sidecar's different again. And slow turns on road is like off road.

It's all damn confusing, easiest just to go out and do it.

John
27th May 2005, 21:44
Yup best way to learn is to get out there - you will find everything pretty much automatic - minds are amazing things..

James Deuce
27th May 2005, 22:11
minds are amazing things..

If you've got one.

I've half a mind

pyrocam
27th May 2005, 22:35
hmm.

first let me say for those of you havent seen my 'wafer thin' tyres. I have the tiniest tyres ive ever seen on a bike. almost chunky pushbike wheels.

ok to the point of 'what feels right;
I feel right doing image 1 of my first post. Im only doing slow (30-60k) turns on an even surface (fucking around while I commute) and it 'FEELS' like I should be on top of the bike. Ive been riding pushbikes long distances and I used to commute through central auckland at rush hour on one and perhaps sometimes a slight lean was in order

am I right in guessing that.
If I am going around a corner on my biscuit tires a low (30-60k) if it feels right I should be as perpendicular to the ground as I feel comfortable with (as in, what feels 'right') but if I were to particapate in a high speed track situation then perhaps a 'lean with the bike' situation might be more in order.

at the moment. I can drive straight with the bike at maybe 15 degree's and myself perfectly straight. and if I want to go around a corner the the bike handles better while on that 15 degree angle but it feels safer with gravity effect pushing down to the earth (therefore pushing the wheel onto the road) than pushing my weight sideways to the road?

John
27th May 2005, 22:45
hmm.

first let me say for those of you havent seen my 'wafer thin' tyres. I have the tiniest tyres ive ever seen on a bike. almost chunky pushbike wheels.

ok to the point of 'what feels right;
I feel right doing image 1 of my first post. Im only doing slow (30-60k) turns on an even surface (fucking around while I commute) and it 'FEELS' like I should be on top of the bike. Ive been riding pushbikes long distances and I used to commute through central auckland at rush hour on one and perhaps sometimes a slight lean was in order

am I right in guessing that.
If I am going around a corner on my biscuit tires a low (30-60k) if it feels right I should be as perpendicular to the ground as I feel comfortable with (as in, what feels 'right') but if I were to particapate in a high speed track situation then perhaps a 'lean with the bike' situation might be more in order.

at the moment. I can drive straight with the bike at maybe 15 degree's and myself perfectly straight. and if I want to go around a corner the the bike handles better while on that 15 degree angle but it feels safer with gravity effect pushing down to the earth (therefore pushing the wheel onto the road) than pushing my weight sideways to the road?

Just a point - tire size means nothing at ALL, big bikes just need more tire space to hold the torque to the ground, the smaller the better in practicality.

On another note, dont try so hard, sounds like your trying to understand more than you can comprehend at the moment...

justsomeguy
27th May 2005, 22:45
Well PYRO the easiest way to do this is find a set of corners you know well and practice riding them.

Try different stances and positions. I feel a more hanging off style is called for while riding your bike due to your 100 width rear tyres.

Practice makes anything easier.:niceone:

pyrocam
27th May 2005, 23:02
Well PYRO the easiest way to do this is find a set of corners you know well and practice riding them.

Try different stances and positions. I feel a more hanging off style is called for while riding your bike due to your 100 width rear tyres.

Practice makes anything easier.:niceone:


I do. I only play around with this stuff on corners I know like the back of me hand. considering Im comuting Im only doing stuff on 90 degree turns but I have a fair bit of leeway.

so. if the size of my tires doesnt matter. then
the big question is. how low can I go.

I can get at most 40 degrees (from my POV) if im fully suited up and keen (+dry weather and grippy road etc)

Bugjuice has said that I can 'lean the crap' out of my tires (btw not his actual words)

I feel that on normal city roads when im not going so fast. im quite alright to go perpendicular to the road (like first post image 1) because it feels right and im not going too fast. but if i was on a corner that has its own lean built in (like a good 22 corner or a track corner) the I could lean the crap out of it and it would slide off into the distance.

I think the 2 things that bother me are
shouldnt the bike slide out if I lean too much into a corner
I dont have the riding experience to try lean the crap out of corner.

John
27th May 2005, 23:07
If your hitting the limits of the tire you will feel the back sliding about, just lift it a little and lean off the bike, and your sweet - I dont think you will have to worry about 'overleaning' at this point, ask ts to tip you out if your real keen on getting on the limits.

pyrocam
27th May 2005, 23:12
If your hitting the limits of the tire you will feel the back sliding about, just lift it a little and lean off the bike, and your sweet - I dont think you will have to worry about 'overleaning' at this point, ask ts to tip you out if your real keen on getting on the limits.

too true.

but curiously, if I overleant. would I be in the gravel rather than have the ability to correct. a back wheel sliding out is a scary thing (see my 'I need new knickers' thread)

I think best to wait until ive done the bronz thing before I argue the point further. Im booked in and paid WOOOHOO

Ixion
27th May 2005, 23:12
hmm.

first let me say for those of you havent seen my 'wafer thin' tyres. I have the tiniest tyres ive ever seen on a bike. almost chunky pushbike wheels.
..

Nah - You have (if my spec sheet is right) 90/90 and 110/90. Yes? Exactly the same as Li'l Rat Bike for width.

Nowt wrong with that for such a light bike. And the rear is large enough to put the power down. After all that's larger than the 4.25 tyres we had to cope with Briddish 650's.

It's not like a car where bigger is better on tyres. In fact on a bike smaller is better. Smaller tyres mean more precise steering. Only reason big sports bikes have bigger tyres is because they'd shred narrow ones. And cos the posers think they look phat.

Even the (750) BMW only runs 100/90 front and 130/90 rear, not a lot more than yours.

Ixion
27th May 2005, 23:22
I do. I only play around with this stuff on corners I know like the back of me hand. considering Im comuting Im only doing stuff on 90 degree turns but I have a fair bit of leeway.

so. if the size of my tires doesnt matter. then
the big question is. how low can I go.

I can get at most 40 degrees (from my POV) if im fully suited up and keen (+dry weather and grippy road etc)

Bugjuice has said that I can 'lean the crap' out of my tires (btw not his actual words)

I feel that on normal city roads when im not going so fast. im quite alright to go perpendicular to the road (like first post image 1) because it feels right and im not going too fast. but if i was on a corner that has its own lean built in (like a good 22 corner or a track corner) the I could lean the crap out of it and it would slide off into the distance.

I think the 2 things that bother me are
shouldnt the bike slide out if I lean too much into a corner
I dont have the riding experience to try lean the crap out of corner.

You won't slide until you reach the shoulder of the tyre , in the dry (wet is another matter). Go rub the edges of your tyres with chalk dust or cement dust, then go for a ride. Lean over as normal. Have a look and see how far you came to the edge of the tread (where the shoulder starts), by seeing how much of the tyre is cleaned off. Now hold the bike and lean it over until its right the way to the shoulder (admittedly the suspension isn't compressed but it'll give you an idea). That's how much more grip you have.

When you do reach the shoulder and the limit of adhesion you hopefully will feel things start to feel "odd" which is the signal to lean off a bit and scrabble around. But my guess is you'll find you've got a long long way to go.

Almost always if you do have a lowsider (the tyre lets go and slides) it'll be because you hit a bump in mid corner or the front got messed up somehow (and you don't have enough power to upset the front I don't think). Watch the bumps and the reverse camber stuff. But ordinary corners you have to lean a hell of a way with modern tyres (Uh, what tyres do you have on - Not Cheng Shins or something ?)

James Deuce
27th May 2005, 23:37
too true.

but curiously, if I overleant. would I be in the gravel rather than have the ability to correct. a back wheel sliding out is a scary thing (see my 'I need new knickers' thread)

I think best to wait until ive done the bronz thing before I argue the point further. Im booked in and paid WOOOHOO

Rear wheel slides are easier to save and can be fun in the long run. Saving front end slides on tarmac is an order of talent above what I have (except for luck), though more power on gravel sorts those out. Stop stressing. You should stay in the saddle, look where you want to go and point your shoulder at the apex of the corner. Look through the corner and you'll find that you are putting your weight to the inside of the bike and turn. This is a good thing as the bike doesn't have to lean as far to turn for a given corner radius or speed.

Most of all mosquito - relax. You're thinking too much.

pyrocam
28th May 2005, 10:21
But ordinary corners you have to lean a hell of a way with modern tyres (Uh, what tyres do you have on - Not Cheng Shins or something ?)

OK I think I have a satisfatory comprehension of it now.

I have done 5000k on my bike but thats proberly a walk in the park for you fullas.

Ill just wait until it gets more natural.

I got a brand new tire from colemans. its Michelen

Pixie
28th May 2005, 11:24
I would have thought it was centrufugal force since your on the 'outside' IE your acting like part of a centrifuge. oh wait.
no.
your right. my bad. centrifuge not a centrufuge my bad
There is no such thing as a centrufuge.
It's best to describe this as angular acceleration as it is an acceleration that is experienced.
What is the force causing this acceleration ? I hear you ask.
It is what ever force that is causing a body to deviate from straight line motion,be it a gravity well around a star causing a planet to orbit or a bike's tyres causing it to corner.

sAsLEX
28th May 2005, 11:38
There is no such thing as a centrufuge.
.
WRONG here is a pic of one http://www.ehs.cornell.edu/lrs/Centrifuge/photos/DCP00613.jpg

used to seperate liquids etc I think

FROSTY
28th May 2005, 11:49
too true.

but curiously, if I overleant. would I be in the gravel rather than have the ability to correct. a back wheel sliding out is a scary thing (see my 'I need new knickers' thread)

I think best to wait until ive done the bronz thing before I argue the point further. Im booked in and paid WOOOHOO
Mate loan your bike to me ,MR,TS or dare I say it Trashman and we will show you how far you can lean on it. Not skiting just i'tll show you you are well withing your bikes abilities.
Ohh and my ol XJ 900 is only running a 100/70/18 front and a 120/70/18 rear
Provided you have reasonably decent tyres you will be able to lean a shit load further than you think you can.
That said with 5000km under your belt I'd definitely do the Bronz course before getting really serious.

Yarg
28th May 2005, 13:05
Get ya self to the Ride Right course by BRONZ asap. they will explain & then u try it. :ride:

Pixie
28th May 2005, 13:13
WRONG here is a pic of one http://www.ehs.cornell.edu/lrs/Centrifuge/photos/DCP00613.jpg

used to seperate liquids etc I think
Used to separate typograghical errors

From the latin Centrum-centre
Fuga -flight

Correct spelling :centrifuge
If you look at the web address of the picture you posted ,you will see it spelt correctly.

scumdog
28th May 2005, 13:26
WRONG here is a pic of one http://www.ehs.cornell.edu/lrs/Centrifuge/photos/DCP00613.jpg

used to seperate liquids etc I think

Look more like an EX-certifuge!! :rofl:

Who was the lucky dude that was standing beside it when it 'hiccupped'?

Toast
28th May 2005, 13:37
Pyro, if it feels a bit dodgy in the slower corners, it could be 'cos you're holding off the power, weighting the front too much.

Weighting the outside peg helps big time too. Once you get used to it, it'll help you build confidence.

But yeah, do your course, then do more miles and focus on what you're doing, you'll have no worries.

2_SL0
28th May 2005, 18:54
Learn to get your line right for the corner, personally I wouldnt worry about the leaning thing to much, that will come with kms. Get out on the bike and practise.

unhingedlizard
1st July 2005, 09:04
we use a centifuge (sp?) at work to seperate Honey and wax. Call it a spin float though....

Leaning i find is a lot like learning to stoppie, the first time you do it you think you are going over the bars. In reality, the back wheel is only 2 inches of the deck.

XP@
1st July 2005, 11:30
Pyro,
Try going in a straight line on an empty road. and just pushing on one bar and then the other keeping your body with the bike. that demonstrates counter steering.
Then keep the bars in line and move your body one side then the other and you see the effect of leaning... nothing.

As for getting lower, easy does it, you are on new tyres, they will still be covered in release agent, which is slippy. you will be able to see the shiny stuff at the edge of your tyre, you want to reduce this slowly. Trying to go all the way over with "Un-Scrubbed" tyres is not good. Just a couple of extra mm each time is the way to go.

surfchick
1st July 2005, 15:19
hey pyro- my tires are skinny too..dey move around alot in the rain...but about the leaning- best thing i did was read up about countersteering... it's like when you do it the bike just drops sideways into the turn and you don't have to go fast to do it. read some articles. also try moving your butt slightly sideways the same way the turn is going- it feels way more stuck to the road...so you can go faster next time..

i know what you mean about pic no. 1- as in you can sort of bend at the waist through turns that way- but its superficial i think and prob not too usefull.

i just came back from a mission morning in the pouring rain up piha way...grrr i slid and slid and slid quietly all the way home... :devil2:

Motoracer
1st July 2005, 15:28
pretty much wrong

"I am refering to the pic attached by sAsLEX on the 1st page of this thread"

I know black guys have been known to be well hung but 3 of them per person and that long and blue!! Shit, that's a new way of shifting the weight to the inside of the corner... Too bad it doesn't work for us normal guys though. :(

ManDownUnder
1st July 2005, 17:15
hey pyro- my tires are skinny too..dey move around alot in the rain...but about the leaning- best thing i did was read up about countersteering... it's like when you do it the bike just drops sideways into the turn and you don't have to go fast to do it. read some articles. also try moving your butt slightly sideways the same way the turn is going- it feels way more stuck to the road...so you can go faster next time..

i know what you mean about pic no. 1- as in you can sort of bend at the waist through turns that way- but its superficial i think and prob not too usefull.

i just came back from a mission morning in the pouring rain up piha way...grrr i slid and slid and slid quietly all the way home... :devil2:

You're 100% right about that... and with practice it'll be a lot of fun throwing the bike around and scooting around those corners... just a bit quicker than you thought you could - but don't go for the "I wonder if I'll live through this"...

Bad approach (esp for a newbie...)
MDU

surfchick
1st July 2005, 17:45
- but don't go for the "I wonder if I'll live through this"...

Bad approach (esp for a newbie...)
MDU

had a few of those moments-you know me...no patience...but i'm trying to be like karatekid..wax-on-wax-off-wax-on-wax-off...when do i get to kick sensei?? :devil2:

justsomeguy
1st July 2005, 17:47
- but don't go for the "I wonder if I'll live through this"...

Bad approach (esp for a newbie...)
MDU

Hehehehehehehee - the famous "I wonder if I'll live through this"... approach :2thumbsup:

Just take it easy Cammo - I too am an overanalytical biker -- but from my experience (6 months now :headbang:) just do what ever feels natural -with time you will get better and realise that it just comes naturally to you and you will be feeling a lot more comfortable.

Here's a good pic I found off KB - of that loony racer - it shows good technique and body position. Also the bike tyres are pretty much as wide as yours.

Good Luck :niceone: