Police training for FortNine.

[Whip]

 

[TSConver]

Motomark does this training in NC if you are interested.

[TEWKS]

“Counterbalancing” is a skill you can take into adventure touring. I’ve used counter standing on the pegs in the loose gravelly turns I encountered recently. 

[9Mary7]

22 hours ago, TEWKS said:

“Counterbalancing” is a skill you can take into adventure touring. I’ve used counter standing on the pegs in the loose gravelly turns I encountered recently. 

Great for slippery surfaces and low speed maneuvers.

[Joe Frickin' Friday]

One thing not mentioned:  your turn radius is limited by how far the handlebars can be turned: when they hit the stop, you can't turn them any further.  

 

BUT...

 

Once your bars are turned full lock, it's possible to decrease the turning radius a bit more by leaning the bike over further.  It's hard to explain in words the geometry of what's happening, but if there were no hard parts in the way and you could lean the bike over until it were almost laying on the ground, you could, in theory, reduce the turning radius to just the length of the bike.

 

ALSO BUT...

 

Maximum lean angle normally happens when you're testing the traction limits of your tires, something you don't want to do during parking lot maneuvers.   So instead of going faster to increase the bike's lean angle, you can counterlean: you lean out, the bike leans in, and you achieve another increment of reduction on your turning radius without having to operate at the traction limit.  

[Hosstage]

Practice, practice, practice.

Preferably with someone else's bike......

[Etienne Lau]

1 hour ago, Joe Frickin' Friday said:

One thing not mentioned:  your turn radius is limited by how far the handlebars can be turned: when they hit the stop, you can't turn them any further.  

 

BUT...

 

Once your bars are turned full lock, it's possible to decrease the turning radius a bit more by leaning the bike over further.  It's hard to explain in words the geometry of what's happening, but if there were no hard parts in the way and you could lean the bike over until it were almost laying on the ground, you could, in theory, reduce the turning radius to just the length of the bike.

......

The turning radius is decreased because the diameter of a motorcycle tire becomes smaller when it's leaned over and therefore your turning radius on the ground tightens up. 

[Joe Frickin' Friday]

54 minutes ago, Etienne Lau said:

The turning radius is decreased because the diameter of a motorcycle tire becomes smaller when it's leaned over and therefore your turning radius on the ground tightens up. 

 

No, it's something different than that.  If your bike were perfectly upright, it would have the same turning radius regardless of whether you were on 17" motorcycle rims or 10" golf cart rims, wheel diameter isn't the issue.  

 

To demonstrate this, I slapped together a SolidWorks model of a bike with the handlebars turned 30 degrees.  In the first scenario, the bike chassis is perfectly vertical, which you can achieve by riding very slowly and leaning your body to the inside of the turn.  I added a red T-square on the ground underneath each wheel, with the crossbar of the T parallel to the tire's line of motion, and the upright of the T intersecting the tire's contact patch.  The point where the two T-squares intersect, far to the left of the bike, defines the center of the turn; the distance of that point from the front wheel's contact patch is the turning radius.  

 

Here's a perspective view of that first scenario (zero chassis lean angle):

 

 

And here's the top-down view:

 

 

The turning radius in this scenario is about 89 inches.

 

Now what happens if you lean the bike over 45 degrees from vertical, while keeping the handlebars turned 30 degrees just like before?  Here's the top-down view of that scenario:

 

 

 

In this scenario, the turning radius has been reduced to about 65 inches.  

 

Just to take it to a stupid extreme, I leaned the bike over to 67 degrees from vertical, i.e. somewhere beyond GP bike territory.  Here's a perspective view:

 

 

 

Rear view (yep, almost laying down):

 

 

 

And the top-down view:

 

 

Note that the handlebars are still only turned 30 degrees from straight, but with the bike leaned this much, the turning radius is down to 51 inches.  This is on a bike with a wheelbase of about 40 inches. 

 

Note that the model I used had very skinny tires, just 1" wide, so their rolling diameter didn't vary much with lean.  I could make these tires a thousandth of an inch wide, and I don't think it would change the geometry of what's happening.  You can see in the model that the effect comes from how the front wheel's contact patch moves forward around the circumference of the tire as the bike leans, changing the angle of the line of movement of the front tire (and where that line's perpendicular intersects the perpendicular from the rear contact patch).

 

You can't influence the lean of a 600-pound motorcycle with your 200-pound body that much, but in the end, you can see from this demonstration that in addition to the maneuvering advantages FortNine discussed, counterleaning definitely does have an effect (a useful effect, I think) on minimum turning radius.  When you're trying to execute a U-turn on a two-lane road with soft sandy shoulders, counterleaning can make the difference between completing your U-turn on the pavement as one clean maneuver and having to do a multipoint K-turn.

 

P.S.:

If anyone is wondering why GP bikes don't turn in tiny circles when they're leaned all the way over, it's because the don't have the handlebars turned all the way to the stop.  In fact, they've barely got them turned at all.  Here's that same 67-degree lean case, but with only 2 degrees of steering input instead of 30 degrees:

 

 

That's about a 42-foot turning radius, which is still awfully tight; a typical highway cloverleaf turn has a radius of about 200 feet.

[BMW_Ken]

Here is another video demonstrating U-turn - counter leaning technique.

 

https://youtu.be/cM4YrRjKVUc

[9Mary7]

 

[Joe Frickin' Friday]

On 8/3/2023 at 3:35 PM, BMW_Ken said:

Here is another video demonstrating U-turn - counter leaning technique.

 

https://youtu.be/cM4YrRjKVUc

 

@4:26 was great: he showed the difference in turn radius when the bike is upright versus leaned, exactly the thing I was talking about.