Is "Beyond Vertical" possible?

I did some advertising design, some time back, and included the phrase: “BEYOND VERTICAL” as a tag on some of the designs.

It came from a story that my cousin told me, of being a passenger on the back of a motorcycle, in which the driver pulled a wheelie, and the bike went “beyond vertical”…meaning the center of the front tire was at like a “one-o’clock” position relative to the center of the rear tire on the ground. My cousin told me the driver was able to bring the front tire down by releasing the throttle. ( Or maybe hitting the rear brake, I don’t remember.)

It sounds possible, and pretty scary. I would think with enough forward momentum, he may be telling the truth.

The client loved the phrase, BTW.

Just wondrin’.

That would place the centre of mass of the bike+rider system quite considerably behind the rear wheel - seems like this would be pretty near impossible to recover from, and with a passenger onboard, doubly so.

Tall tale, exaggerated in the telling is a far more likely explanation

To expand on the above - a quick google image search of motorbikes pulling wheelies suggests that (subject to all sorts of variables) a 45 degree tilt is about enough to balance the bike on the back wheel, so even a tilt between 45 and vertical is going to be enough to dump the rider on his arse on the tarmac in a split second.

I have no doubt a motorcycle could be put in that position. I have considerable doubt about whether the rider would walk away from the attempt. Sounds like one of those “Hey Y’all watch THIS” moments that rarely end well.

Sure, it could pass through that position.

If the motorcycle is moving forward, applying the rear brake will cause the rear wheel to be slowed relative to the rest of the bike. This should make things tend to return to normal.

Yes, but for the front wheel to be above and behind the rear wheel, in this ‘beyond vertical’ position, things have already strayed very far from normal. I doubt a return is possible.

I am voting for quite possible, but under certain conditons, of which I am too tired to type out at the moment. And allowing for the fact I may be missing something critical and obvious.

Max Biaggi used to pull that kind of a stunt occasionally. I absolutely do not see how, but he’d go well past 12 o’clock.

http://www.youtube.com/watch?v=8BA2clO3WFE

thanks.

That was fucking awesome!

It was pretty awesome, but because of the camera angle, you cannot tell quite how vertical (or beyond) he really was.

In a normal wheelie, the torque provided by applying power to the back wheel provides the rotational moment about the rear axle that lifts the front of the bike. That power needs to be maintained to keep the bike up. Once the bike is vertical, any additional torque will rotate the back wheel under the front till that CoM is behind the line joining the axles, and the bike will fall. Given that the CoM of a racing bike is somewhat lower than the line between the front and rear axle, there is a bit of leeway - when the bike is exactly vertical, the CoM (and thus the rotational moment round the rear axle) should be just to the front of the bike if the rider is light enough not to provide a counter moment. This makes the vertical position recoverable. However, going beyond vertical increases the riders moment backwards, and rapidly reduces the forward moment - you won’t get much time before the backward moment takes over. At that point, to recover you need to induce a forward moment round the rear axle by braking hard enough to allow the momentum of the CoM to swing forward round the rear axle to get back to a more maintainable position.

So a power blip near vertical could start the rotation beyond vertical, followed by a rear braking action that counters and rotates the bike forward again.

Sounds pretty risky to me, probably impossible to co-ordinate, and a recipe for disaster. And you could not hold the beyond vertical position - it would be dynamic. I would need to see lots of good side-on video to believe that is is actually doable.

Si

Just as application of power will accelerate the rear wheel forward under the bike during a normal wheelie, application of rear brake will accelerate the rear wheel backward (i.e. decelerate it) so that the CoM of the chassis can come forward of the wheel’s contact patch again. Just as heavy application of the front brake can bring the chassis up onto the front wheel from a dead-level position (called a stoppie), it should be possible (via heavy application of rear brake) to recover from a standard wheelie even when the bike/rider CoM is way behind the rear wheel’s contact patch. At some point when you go way past vertical I expect it gets difficult to maintain one’s grip on the bike, and you end up falling straight down out of the saddle onto the pavement. Ouch.

If you’ve ever watched observed trials riders, a beyond-vertical wheelie is the kind of stunt they would excel at.