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Old 01-04-2015, 07:48 PM   #101
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Wouldn't that depend on how fast you're going?
I mean, it's possible to lean the bike but go in a straight line.
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Old 01-04-2015, 09:09 PM   #102
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Quote:
Originally Posted by bumblebee View Post
Wouldn't that depend on how fast you're going?
I mean, it's possible to lean the bike but go in a straight line.
Your center of Gravity is still going to be straight up and down. The lean angle we are talking about is not the bike but the combine rider/bike system.
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Old 01-04-2015, 10:23 PM   #103
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Quote:
Originally Posted by kenup283 View Post
Funny you mention it.
Good post. All legit thoughts.

FWIW, I take the carousel mid corner going CCW at about 80 - 85 MPH on my Ninja 250, top of 5th gear, sometimes 6th. ~1.2 g's sounds about right on that bike on good DOT race rubber, if I had to guess.

And we're getting to the heart of the issue....combined rider / bike CG in all 3 axis tremendously affects bike performance, and performance is compromised in some way no matter which way you move that CG. Also important is inertial moment, or the force required to rotate the bike around any of the 3 axis. A bike that has the same CG but with the weight distributed froward and backwards, and not clumped around the center and rider, will be easier to explore braking and accelerating limits. But will be harder to rotate when making a u-turn. Again, what are we trying to engineer?????
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Old 01-05-2015, 10:13 AM   #104
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We aren't trying to engineer anything, OP just wanted to compare different bikes max lateral g's.

On the 250 do you only do 85 there because that's all the 250 can get up to or is that the limit of grip? Seems like it should be able to go faster(given it ha enough power to get up there)
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Old 01-05-2015, 12:22 PM   #105
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2.2g seems insane though that turn , props to the Miata. Wonder what modifications it had.
I think it would be simple enough to just put the same the cars use to measure G on the bikes and have some crazy run them all lol.

Really just want the numbers for curiosity I know its not that important. although some car guys act like its
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Old 01-05-2015, 12:27 PM   #106
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Some people also think lowering , extending the swing arm and adding chrome makes a bike handle corners better.
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Old 01-05-2015, 06:20 PM   #107
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Mr.P by any chance do you do 55 mph around the keyhole?

Ark.Dave, that Miata would be in kart territory. At those g' a bike would be pushing 65 deg, going to be out of reach but I think you knew that already.

Max g's, the idea is that cornering force must be balanced by leaning into the turn. The g's can be related that angle. It takes out the need to know what the radius and speed are. For example, an 85 mph 120 m corner is 1.2 g, same as a 55 mph 50 m corner, both require the same lean angle to balance the cornering force with the bike + riders weight, and both generate the same lateral g's.

But again I am only describing the lateral g's, I am not trying to explain how they are achived.


650ninja, my answer is that all sportbikes will be capable of over 1 g. Add a good rider and rubber then 1.2 - 1.4 g. These are values based on what is or has been demonstrated. They can be reversed calculate (if we prefer to think about it that way) to lean angles of 45, and 50 - 55 deg.
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Old 01-05-2015, 07:06 PM   #108
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How do you arrive at the conclusion that all bikes are capable of over 1 lateral g? Tires, suspension, sprung and unsprung weight, cg, rake and trail all vary bike to bike.
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Old 01-05-2015, 07:47 PM   #109
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Quote:
Originally Posted by kenup283 View Post
Mr.P by any chance do you do 55 mph around the keyhole?

Ark.Dave, that Miata would be in kart territory. At those g' a bike would be pushing 65 deg, going to be out of reach but I think you knew that already.

Max g's, the idea is that cornering force must be balanced by leaning into the turn. The g's can be related that angle. It takes out the need to know what the radius and speed are. For example, an 85 mph 120 m corner is 1.2 g, same as a 55 mph 50 m corner, both require the same lean angle to balance the cornering force with the bike + riders weight, and both generate the same lateral g's.

But again I am only describing the lateral g's, I am not trying to explain how they are achived.


650ninja, my answer is that all sportbikes will be capable of over 1 g. Add a good rider and rubber then 1.2 - 1.4 g. These are values based on what is or has been demonstrated. They can be reversed calculate (if we prefer to think about it that way) to lean angles of 45, and 50 - 55 deg.
I did and now that you have admitted that the Miata has more grip we can settle the bike vs car grip debate.
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Old 01-05-2015, 08:22 PM   #110
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Old 01-05-2015, 08:24 PM   #111
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Old 01-05-2015, 09:10 PM   #112
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Quote:
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Failed. Lean angle has nothing to do with how many G's you can hold. Isn't this the reason why moto guys hang off the bike so that their lean angle is LESS to achieve HIGHER G's. If it is all about the lean angle, no one would hang off the bike lol...
There is so much retarded in your last two post I can't handle it. People hang off the bike to increase the lean angle of the center of gravity but keep the bike more upright and on the meaty part of the tire. So most of the time lean angle is referenced to the lean angle of the bike not the center of gravity since that would be near impossible to know without some fancy math. This conversation though requires you to be able to differentiate between the two.

Your second post is just silly, of course there is no lean angle between the contact patch and your center of gravity, you're going in a straight line.

I'm guessing you didn't read the whole thread did you? Just jumped to the last page and thought you were an expert because you watched a motogp race once before?
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Old 01-05-2015, 09:14 PM   #113
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Old 01-05-2015, 09:20 PM   #114
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Quote:
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I am not the one that is silly. Bringing up the angle of position of the center mass relative to the friction point is MOOT. The one and only bottle neck for achieving higher laterial G is TRACTION (a function of static coeficient between tire and concrete, and perpendicular force) , not angle of where the center of mass relative to the friction point is... I am 100% positive on this...
Then why exactly do bikes need to lean while cornering?
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Old 01-05-2015, 09:31 PM   #115
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Old 01-05-2015, 09:44 PM   #116
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Answer my question and you will find why you're silly. The bike needs to lean in a corner to overcome the roll torque. This balance between lateral g's and lean means that if you pull too much lateral g's without enough lean angle you roll over to the outside. Conversely if you lean more than the lateral acceleration you will fall down or lowside. So no a bike at the limits of its grip cannot lean more, that is how lowsides happen. If you would like to read more google bicycle and motorcycle dynamics wiki. Great explanation of why you're stupid and that lean angle between the center of mass and the plane of the contact patch is connected with lateral acceleration.

In this thread we have also gone over that you achieve the grip to lean the bike through the friction generated by the tires suspension chassis etc.

Another example is going back to the Harley, let's put motogp super soft compound tires on a Harley and assume they can stay at optimum temp. Max lean angle of most Harley's is like 20 degrees. Lets even assume it has the perfect suspension and chassis, how much lateral acceleration do you think this Harley can achieve? The answer is the same as any other bike at 20 degrees of lean angle given that bike also has enough traction.
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Old 01-05-2015, 09:55 PM   #117
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Quote:
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Great explanation of why you're stupid...
Why you gotta say like this?
You're both making good points, although neither of you is understanding the other. There's no need in turning into a keyboard badass in the middle of it.
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Old 01-05-2015, 09:55 PM   #118
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Old 01-05-2015, 09:59 PM   #119
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Quote:
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Why you gotta say like this?
You're both making good points, although neither of you is understanding the other. There's no need in turning into a keyboard badass in the middle of it.
Yeah you're probably right, except I understand that he doesn't fully understand the dynamics of a two wheeled vehicle.
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Old 01-05-2015, 10:02 PM   #120
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