Safe Speed Forums

Hit the tree square on, from an airbourne condition, due to other traffic at the jump, this also destroyed the tank.



No better test's for body armour than hitting a tree which is far harder than a car, the tree will not deform. Body Armour is not 100%, for protection, but it goes a long way.

It is the basis of my planning for accidents.

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Steve

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Steve

ROTFL! My thoughts exactly.

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

Beats reality TV anytime....

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Speed camera policy Kills

If the crash was inevitable a manoeuvre to the right would be a waste of time, better to lift the left leg and push off with the right leg while curling your body with the left shoulder down just before being hit. In this way your left shoulder would strike the bonnet of the car and you would roll over it and into the windscreen and then possibly over the car and onto the ground. Far better than having your left leg amputated due to the massive injuries caused by having it crushed and then the added injuries as your head is slammed into the bonnet.

As I have not ridden a bike for many years I contacted a close friend who is about my age (50) and rides long distances almost every weekend with his wife. When I described this discussion he also wholeheartedly endorsed the jump and leg lift / roll options and indicated that this is exactly what he would try and do.

He also added another scenario he encountered where due to painted lines and wet weather he ran up the back of a car. This happened in his early years and he just sat on the bike. His knees, followed by his shins, struck the handlebars and caused some very painful and long term injuries. He now sais that if the situation occurred again he would attempt to leap off the bike just prior to impact so as to hit the boot, rear windscreen or roof of the car as he feels it would be by far the lessor of the two evils.

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Ross

Yes I'm a hoon, but only on the track!!!!

However, we now have armour that would take that impact & protect his knees.

Just to further the effectivness of armour, which is developed into its current standard. The development by the main makers, shoe for helmets, sidi for boots etch.

The development is from racing, with accidents upto 200 mph, which is far in excess of your typical road accident.



This is a leap of faith, with results that can never thought out of your final position. The are a number of forces that cannot be taken into account, and these forces have the final decision on where your body is thrown.

Your friend damaged his knees, which is far better than hitting his head on the car, by which may easily of killed him. The bike would of absorbed most of the impact in this scenario, and for me is the ideal situaction.

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Steve

I certainly cannot lift my leg off my bike with my wife on the back, (my bike is about as big as they get, K12LT), as her leg is tucked up behind mine. A pillion would without doubt eliminate any form of jumping off.

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Steve

Who said anything about a pillion?

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Ross

Yes I'm a hoon, but only on the track!!!!

So, if I offered you a bike and a racetrack (no slow corners) you would be happy to ride it around after I 'adjusted' the head bearings so that the bars were locked in the 'straight ahead' position? I'm not convinced leaning the bike would get you round. Actually, I'm not convinced the bike would be willing to lean that much in the first place See you in the gravel trap at turn 1

For a more technical explanation of why steering is important for cornering see http://www.superbikeschool.com/machiner ... achine.php . The clip is 1.3MB but is worth a viewing if only to prove to you that you are, in this case, incorrect. Steering, or more accurately, counter-steering, is essential to get a bike to turn.

You said earlier that you raced bikes. Were/are you any good?

[edited by SafeSpeed to fix the link - the trailing period was causing a 404 error]

That's a good article, thanks for posting. But it isn't the whole story - there's no technical mystery about how counter steering works and conventional steering has an essential role to play as well.

Countersteering is used to initiate and terminate leans. It works very simply by dragging the contact patch out from under the centre of gravity(CoG). With the contact patch offset from the CoG the bike starts to fall over - that's how a lean is initiated with counter steering. The big advantage of counter steering is that you don't need to move the CoG where the bike's mass acts. That's why it's quick - you're turning the bike's mass around the CoG in the roll axis.

But conventional steering plays an important part too. (You can try this part with a push bike without even turning a wheel) When the bike is leaned over the contact patch trail from the steering axis (the castor angle) ensures that the 'conventional' steering angle matches the lean angle. This conventional steering is required for constant radius, constant speed, constant lean cornering. You still use countersteering to lower the lean angle. Raising the lean angle works in very much the same way using the same effect...

At the end of cornering the countersteering effect is used to stand the bike back up - but this time you actually push the bars in the conventional direction. Suppose you're reaching the end or a right hand curve - you want to stand the bike back up. This is effectively equivalent to initiating a left lean so you steer right to accomplish it. As you steer right the net vector of centrifugal force+gravity moves to the left of the contact patch resulting in an anticlockwise acceleration around the roll axis restoring the bike towards the vertical.

[yes, I know there's no such thing as 'centrifugal force', but it does help to keep the explanation manageable]

I do suspect that it is entirely possible to operate and control a bike without countersteering - weight shifts and conventional steering together will do the job - and I well recall being able to steer my push bike with no hands on the handlebars. It's just that countersteering is much faster and more controllable.

I remember finding an excellent animated diagram showing the effect of countersteering on lean and CoG, but sadly I can't find it again.

And by the way, gyroscopes have absolutely nothing to do with any of this.

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

Spoken like an engineer.

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Make everything as simple as possible, but not simpler - Einstein

Yes, I steer like that too - I just flop my beer gut over to the other side of the tank and gravity does the rest. I believe a more conventional method involves counter-steering , which may or may not involve gyroscopic precession. I understand that 90 deg. out-of-plane forces are caused when the axis of a rotating wheel is turned, which could contribute to the forces that lean the bike over – I don’t know enough about it. In any case, beer gut steering might work with fixed head bearings, but you need to turn the bars a tiny bit for the other methods!

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I stole this .sig

No, you're not going to 'troll' me (a 'Newbie' here) on this.

First you slate the 'jump' - which clearly is a well-known technique, and in the right situations can be a life-saver.

Then, you deny any knowledge of counter-steering - despite you being a high-mileage, ex-racer, motorcyclist.

Next you'll be telling me you don't squeeze the clutch in during emergency stops!

Does 'Basingwerk' refer to Basingrad in North Hampshire?

If so, see if either Cooper Reading or SPC at Faringdon have a BMW C1 you can have a go on.

No tank to press your knees against, no footrests to 'weight', and you're strapped in to the car-style seat - so definately no body (gut) movement.

They're a hoot!

Then if you're feeling brave, stump £55Kplus and get one of these:
http://motorcyclecity.com/bikewatch/Eco ... bile62.jpg

http://www.peraves.ch/ndexe.htm

No, it refers to Basingwerk Parchment, a special type of paper. Are you affilicated to the Horse Council by any chance?

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I stole this .sig

I thought it was Basingwerk Abbey in Holywell I recall. Or odes basingwerk parchament come from there too ?

Nah, today it's more 'Hoarse'.

Well known with who, what training establishment trains riders to jump in the event of an impending accident



No mention of counter steering, the post was steering

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Steve

You did, see below

[/quote]

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Steve

Mrs miggins, you are have mis understand the format of the post.

The comment was regarding the format of the body weight regarding a particular accident.

My point being that the bike would be leaned to the right to turn right. Now if you look at your own clip you will in fact see the bike is leaned to turn, at no time is the bike kept straight, and just turning the handle bars to turn.

My comment is completley accurate

Bikes are turned by leaning, countersteer is irrelevant to the point being made.

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Steve