Go Back   Horizons Unlimited - The HUBB > All Miscellaneous questions > Travellers' questions that don't fit anywhere else

Travellers' questions that don't fit anywhere else This is an opportunity to ask any question, and post any notice you wish that doesn't fit into one of the other sections.
Contact Overland Solutions for all your custom modifications and setup for overland travel.

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 10 Nov 2004
Gold Member
Veteran HUBBer
 
Join Date: Mar 2004
Location: Gwynedd, Wales, UK
Posts: 252
Steering a bike

Ever thought about how much you need to actually turn the handlebars of your bike to go round corners?

Suppose you come up to a bend at, oh, sixty mph, then by how many degrees do you turn the steering... well, today I went and found out. I stuck a twig on to my instrument cluster at the middle of the handlebars with insulating tape so that when I turned the steering the end of the twig would sweep over the dash and give some idea of how much I was turning the bars.

No, scientific it wasn't, but it showed that I was not turning the bars AT ALL. Not a sossidge. Agreed, I must have been doing something to get round the bends, but I didn't seem to be steering it round. Mind, it's quite different at low speed, roundabouts etc. And reverse steering too, that's something else again.

Just thought I'd mention it, that's all.

John

------------------
Johnefyn
__________________
Johnef
Reply With Quote
  #2  
Old 10 Nov 2004
Steve Pickford's Avatar
Contributing Member
Veteran HUBBer
 
Join Date: Jul 2003
Location: Oxford, UK
Posts: 1,027
It's called Counter Steering.

At low speed, more steering input is needed. As you speed up, the required input is reduced until you actually need to turn the bars very very slightly in the opposite direction of the direction you want to go.

The amount of counter steer & the point at which you need to apply it varies from bike to bike.

Most of us to it wothout even realising it anyway. I had a dramatic intro to counter sttering on my first fast bike (Jota, the five barred gate of the bike world lol). Flying up a dual carraigeway at about 100mph. I decided to realy attack the long sweeping left hand bend up ahead. I was on the inside lane & gave the bars a good tug to the left..... To my surprise & horror, the bike turned right quite sharply, shot across the outside lane, came close to ramming the Armco barrier at 90mph. Taught me a huge lesson.
__________________
My photos: www.possu.smugmug.com
Reply With Quote
  #3  
Old 10 Nov 2004
Registered Users
Veteran HUBBer
 
Join Date: Sep 2004
Location: Salisbury UK
Posts: 161
This is a fasinating post.

I belong to a road bike club and we do a counter steering course to make people aware of the way it works. It is wonderful when people ride thinking about it and it improves their cornering no end.

It is complex but basically I understand that the front wheel acts as a gyroscope (remeber the way a bicycle wheel acted as a kid when you span it holding the axle and it felt it had a mind of its own).
As you press lightly on the opposite bar the gyro acts to lean the bike and you move onto the smaller diameter of the rear and front tyre this like a rolling cup makes you go around in a cirle. the more you lean the bike by pressing on the bar the smaller the circumfirance and so the tighter the turn. Thats why bikes have rounde cross sections to their tyres. Espcially fast turning sports bikes.

At very low speeds you will steer normally but anything over 15mph you instinctivly countersteer until you think about doing something else like the previous poster.

Better explaination here:http://www.msgroup.org/TIP048.html

Charlie
Reply With Quote
  #4  
Old 10 Nov 2004
Gold Member
Veteran HUBBer
 
Join Date: Mar 2004
Location: Gwynedd, Wales, UK
Posts: 252
Hi Steve

Soon after passing my test, a long long time ago, I was riding my little Honda 185 along a twisty country lane with my girlfriend on the pillion when we met a car coming the other way, just on a corner, 10mph or so. Following a brief panic I duly swerved and we got past ok. But it worried the shit out of me that all I could remember after, and in absolute crystal detail, was of briefly steering TOWARDS the approaching car. It took me a couple of years to realise that I was counter steering, and that that is really the way we all steer at low speed when we need to turn quickly. Until this dawned on me I was convinced that, deep down I was suicidal and that I had a latent desire to kill both my girlfriend and myself.

Funny how we learn to ride a bike, steering and balancing in all these different ways and not knowing exactly what it is we learn (how many riders appreciate the notion of counter steering- yet we all do it)(and come to that what do I know about the gyroscopic forces involved with steering a spinning wheel?) So, as in so many things, don't think too hard, just do it.

And, yep, my wife and me- we're both still here!


------------------
Johnefyn
__________________
Johnef
Reply With Quote
  #5  
Old 10 Nov 2004
simmo's Avatar
Contributing Member
Veteran HUBBer
 
Join Date: Nov 2002
Location: melbourne
Posts: 557
Hi John

you should notice that if you push the inside of the handle bar in the direction you want to turn it goes that way...in fact you are steering the bike the other way ie pulling the opposite bar towards you. There is no dramatic turning of the wheel but you are having sufficient impact on the gyroscopic forces to produce a result.

You can use this to make quick evasive turns at low speed by pushing on one bar then quickly pushing on the other.

If you can get a small bicycle wheel on an axle, spin it holding the axle ends then try to move the spinning wheel from a vertical axis. It takes quite a large initial effort then you have apply effort to stop it toppling over.

If you look at some photos of bike racers cornering at high speed you can see clearly that the front wheel is pointing away from the direction of the turn..of course the extreme version is the high speed power slide.

Some people have suggested that using countersteering can have a negative effect on front wheel grip in corners and weight transfer and weighting of the footpegs gives a better result...but I find that you would have to be going pretty hard, already well into the turn or being quite violent on direction changes for it to have much of a negative effect.

You would also notice that in very very low speed turns, such as tight carpark figure of eights, you lean away from the bike, so its like you are pushing the bike down, quite the opposite to a normal or high speed turn where you lean into the corner.

But at least its not as confusing as trying to ride a sidecar!!!!!!

cheers

alec
__________________
Close to Antarctica and a long way from reality
Reply With Quote
  #6  
Old 10 Nov 2004
Gold Member
Veteran HUBBer
 
Join Date: Mar 2004
Location: Gwynedd, Wales, UK
Posts: 252
Hi Simmo (Alec)

Or a tricycle! I was on a 'Star Riders' instructor's course many moons ago (are they still going?) and one of the other instructors who was a motorcycle dealer turned up with a Honda 3- and 4-wheel ATV on a trailer, you know, like farmers have as runabouts on their farms. Well, talkabout laugh, we laughed ourselves silly. Thing was, we'd just been doing slow riding on our own bikes through/around the traffic cones on the yard, so we were all in the two wheel mode and found it all but impossible to change the whole mindset to handle the three and four wheelers.

Hey- this thread's got awfully inteletchiwul all sudden (and why not.) I did know that I wasn't moving the bars a lot but until the Twig-and-tape experiment I really didn't realize how little.

Braindead: thanks for that, it's going to take just a little while to digest the contents of the site you mentioned, there's a whole lot of heavy stuff in there.

As for gyroscopes, I've never been able to get my mind around those, despite having tried. On the subject of the gyroscopic action of the wheels, I wonder what would happen if you could mount a wheel geared to spin in the opposite direction to the roadwheel and mounted side by side with it so as to cancel the gyroscopic effect; perhaps it would end up behaving like the ski you mentioned?

My brain hurts

John

------------------
Johnefyn
__________________
Johnef
Reply With Quote
  #7  
Old 10 Nov 2004
Registered Users
Veteran HUBBer
 
Join Date: Sep 2004
Location: Salisbury UK
Posts: 161
The mounting of wheel spinning in an opposite direction would have the effect you suggest. Thats how balancing sg=hafts work in agines to produce a 90degree our of phase wave to cancel out the vibration.

The trick is not to think about why it works but to practice how it works on the road/ rack.

Cheers

Charlie
Reply With Quote
  #8  
Old 10 Nov 2004
Gold Member
Veteran HUBBer
 
Join Date: Mar 2004
Location: Gwynedd, Wales, UK
Posts: 252
Hi Charlie

You've got me there. I didn't know that the gyroscopic effect came into balancing out vibrations, I just assumed that a balancer shaft merely produced an equal and opposite vibration to cancel out the source of the vibration. Where can I read up on that- is it mentioned in the website you just mentioned- as I said, my brain's already hurting with that one!

Thanks

J

------------------
Johnefyn
__________________
Johnef
Reply With Quote
  #9  
Old 10 Nov 2004
Registered Users
Veteran HUBBer
 
Join Date: Sep 2004
Location: Salisbury UK
Posts: 161
They do exactly as you say produce oppostite viabraitions, but they also conter act the gyroscopic affect of the spinning parts, Have you ever rode a transverse twin like a Guzzi or a BMW Honda CX they lean over to the right when acceleration to stop this many are fitted with balance shafts that conteract the movenment to help them run starighter.

Charlie
Reply With Quote
  #10  
Old 10 Nov 2004
Steve Pickford's Avatar
Contributing Member
Veteran HUBBer
 
Join Date: Jul 2003
Location: Oxford, UK
Posts: 1,027
I thought balance shafts were primarily to cancel out vibes? Plenty of bikes run balance regardless of crank layout, makes for a smoother ride but adds to the mass that needs to be moved, thus affecting how fast the engine can spin up.

Plenty of big singles run balnce shafts, my DR600 had two. I thought their mass was calculated to cancel out or equal the mass of the conrod, piston & a percentage of the cranks weight?

BTW no BMW twins have ever had a balance shaft fitted with the exception of the new 1200GS.

A more common way of cancelling out torque reaction is have a contra-rotating gearbox. This spins the opposite way to the crank. Having alternators/generators contra-rotate has a similar but reduced affect due to lack of mass.

[This message has been edited by Steve Pickford (edited 10 November 2004).]
__________________
My photos: www.possu.smugmug.com
Reply With Quote
  #11  
Old 10 Nov 2004
Gold Member
Veteran HUBBer
 
Join Date: Mar 2004
Location: Gwynedd, Wales, UK
Posts: 252
Hi Charlie

I would say that the lurch you get on blipping the throttle on a transverse engine (mine's an '82 Boxer) is due to torque reaction rather than a gyroscopic effect.

In all honesty, though, I must admit that other than when stationary and blipping the throttle I've never noticed any adverse effect due to this; whether that's because my little botty is not sensitive enough, sweetie, or whether it's simply because I've always lived with it.(R51/3, R60/5, R100RT, R100RS)

Having said that, though, it is true that the revs shoot up a lot more quickly when the bike is in neutral than when its in gear and actually driving the bike, so it does seem that the amount of lurch is to do with the rate of CHANGE of rpm rather than the actual rpm. Um, yes. I think.

Cheers

John with the hurting brain

------------------
Johnefyn
__________________
Johnef
Reply With Quote
  #12  
Old 10 Nov 2004
Gold Member
Veteran HUBBer
 
Join Date: Mar 2004
Location: Gwynedd, Wales, UK
Posts: 252
Steve,
1. lol?
2. BTW?
J.

------------------
Johnefyn
__________________
Johnef
Reply With Quote
  #13  
Old 11 Nov 2004
Steve Pickford's Avatar
Contributing Member
Veteran HUBBer
 
Join Date: Jul 2003
Location: Oxford, UK
Posts: 1,027
Quote:
Originally posted by John Roberts:
Steve,
1. lol?
2. BTW?
J.

lol = laugh out loud
btw = by the way
iirc = if I remember correctly
afaik = as far as I know
stfu = shut the *** up

There are a few others I can't remember at the moment.


__________________
My photos: www.possu.smugmug.com
Reply With Quote
  #14  
Old 11 Nov 2004
Gold Member
Veteran HUBBer
 
Join Date: Mar 2004
Location: Gwynedd, Wales, UK
Posts: 252
Steve

Ah, now I see. Thanks.

Going back to your comments re balancing of the crank etc. I came across another application of that sort of thing regarding balancing steam locomotive coupling- and connecting- rods.

These had to be balanced because the mass of these rods going up and down as the wheels went round resulted in a vicious hammering action on the rails. The coupling rods connecting the driving wheels together were balanced relatively easily by having balance weights on the wheel rim, the thing was, with coupling rods both ends went up and down and around with the wheel. The case of the connecting rod, however, is different because only one end of this rod actually goes around with the wheel, the other one simply sliding backwards and forwards as it is pushed and pulled by the piston, and in this case like you said, only a percentage of its weight was balanced out. I think I remember that was something like a third of its weight, though I would have thought it should be more like a half. If anybody is particularly interested perhaps Marks' Standard Handbook would tell us, I could dig it out. It seems to be the same principle as that of a bike engine, albeit on a different scale. Anyway, when you think of the size of the rods on one of the big locos then you can imagine what a hell of a beating they could give the rails when thrashing about doing a ton.

John

PS just read your letter again Steve. Yes, I'm sure you are correct; the mass of the piston should be included with that of the conrod and it is a percentage of that total that is balanced.

J

------------------
Johnefyn
__________________
Johnef
Reply With Quote
  #15  
Old 25 Feb 2005
Contributing Member
New on the HUBB
 
Join Date: Apr 2001
Location: USA
Posts: 16
Uhh, Guys,

The gyroscopic effect of your front wheel has a limited amount of effect on turning (countersteering). I did the calcs a while ago. Remember, there is an equal or greater gyroscope in the rear, called your rear wheel. It takes a bit of energy to make that lean over.

The basics of how it works (and a lot easier to understand than a gyroscope) is to remember that a mass in motion wants to remain in motion. The mass of a motorcycle can, for this purpose, be thought of as a point mass somewhere near the center of your bike. That point wants to go straight. Imagine a bike standing still on ice, if you held the center of the bike in one place and slid the tires to the left, the bike would fall over to the right. Now if you are moving and you turn your handlebars counterclockwise (to the left) the center of the bike wants to go straight ahead but the bottom the wheels) go left, forcing the bike to lean to the right. Now that you are leaned over, you are turning to the right.

Now, the gyroscopic effect is VERY useful in keeping a bike stable.

Ain't physics grand!

------------------
CT_Bob@juno.com
__________________
Bob L.
New Hampshire
WEB: www.angelfire.com/trek/ct_bob
Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 Registered Users and/or Members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


 
 
 

NEW! HU 2015 Motorcycle Adventure Travel Calendar is now available! Get your copy now for some terrific travel inspiration!

HUGE, 11.5 x 16.5 inches, beautifully printed in Germany on top quality stock! Photos are the winning images from over 600 entries in the 9th Annual HU Photo Contest!

Horizons Unlimited 2015 Motorcycle Adventure Travel Calendar.

"The calendar is magnificent!"

"I just wanted to say how much I'm loving the new, larger calendar!"

We share the profit with the winning photographers. YOU could be in the HU Calendar too - enter here!

Next HU Eventscalendar

See all events

 

Latvia to Australia, an inspirational 5 month journey full of unexpected adventures!


Renedian Adventures

Renedian Adventures

What others say about HU...

"I just wanted to say thanks for doing this and sharing so much with the rest of us." Dave, USA

"Your website is a mecca of valuable information and the DVD series is informative, entertaining, and inspiring! The new look of the website is very impressive, updated and catchy. Thank you so very much!" Jennifer, Canada

"...Great site. Keep up the good work." Murray and Carmen, Australia

"We just finished a 7 month 22,000+ mile scouting trip from Alaska to the bottom of Chile and I can't tell you how many times we referred to your site for help. From how to adjust your valves, to where to stay in the back country of Peru. Horizons Unlimited was a key player in our success. Motorcycle enthusiasts from around the world are in debt to your services." Alaska Riders

contest pic

10th Annual HU Travellers Photo Contest is on now! This is an opportunity for YOU to show us your best photos and win prizes!

NEW! HU 2014 Adventure Travel T-shirts! are now available in several colors! Be the first kid on your block to have them! New lower prices on synths!

HU 2014 T-shirts now in!

Check out the new Gildan Performance cotton-feel t-shirt - 100% poly, feels like soft cotton!


What turns you on to motorcycle travel?


Global Rescue, WORLDwide evacuation services for EVERYONE

Global Rescue is the premier provider of medical, security and evacuation services worldwide and is the only company that will come to you, wherever you are, and evacuate you to your home hospital of choice. Additionally, Global Rescue places no restrictions on country of citizenship - all nationalities are eligible to sign-up!


New to Horizons Unlimited?

New to motorcycle travelling? New to the HU site? Confused? Too many options? It's really very simple - just 4 easy steps!

Horizons Unlimited was founded in 1997 by Grant and Susan Johnson following their journey around the world on a BMW R80 G/S motorcycle.

Susan and Grant Johnson Read more about Grant & Susan's story

Membership - help keep us going!

Horizons Unlimited is not a big multi-national company, just two people who love motorcycle travel and have grown what started as a hobby in 1997 into a full time job (usually 8-10 hours per day and 7 days a week) and a labour of love. To keep it going and a roof over our heads, we run events (22 this year!); we sell inspirational and informative DVDs; we have a few selected advertisers; and we make a small amount from memberships.

You don't have to be a Member to come to an HU meeting, access the website, the HUBB or to receive the e-zine. What you get for your membership contribution is our sincere gratitude, good karma and knowing that you're helping to keep the motorcycle travel dream alive. Contributing Members and Gold Members do get additional features on the HUBB. Here's a list of all the Member benefits on the HUBB.


Books & DVDs

amazon

All the best travel books and videos listed and often reviewed on HU's famous Books page. Check it out and get great travel books from all over the world.


Motorcycle Express for shipping and insurance!

Motorcycle Express

MC Air Shipping, (uncrated) USA / Canada / Europe and other areas. Be sure to say "Horizons Unlimited" to get your $25 discount on Shipping!
Insurance - see: For foreigners traveling in US and Canada and for Americans and Canadians traveling in other countries, then mail it to MC Express and get your HU $15 discount!




All times are GMT +1. The time now is 05:43.