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Discussion Starter #1 (Edited)
It's often said that 250's will eat 600's in the corners. I have never understood whether this statement is implying that:

1. It is possible for a really good rider to surpass an average 600 rider in the corners

2. Or does the lighter weight/geometry of the 250 allow for greater lean angles/stability/etc in the corners...?

Obviously the first is true but what about the second?
 

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It's about carrying speed in the corners. With equal grip available on both bike's tires, the 250's lower mass
will be less taxing on the tires. This allows greater speed and lean angle.
 

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Discussion Starter #3
I see. Thanks.
 

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Yeah, but if we're talking Ninja 250 VS newer 600, it usually comes down to #1 unless the 250 has some nice suspension upgrades.
 

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nig said:
Yeah, but if we're talking Ninja 250 VS newer 600, it usually comes down to #1 unless the 250 has some nice suspension upgrades.
With equal riders, equal tires and corner speeds, it comes down to physics.
And the lighter bike (250 two-stroke, or Ninja) will have higher cornering speed potential.
 

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If the bike was a Ninja 250, the rider would have to be quite a lot better to beat a 600.

If you're talking about 250 2 stroke gp bikes, they are pretty close to a 600 in power to weight ratio and I would think it would boil down to whichever rider is better.
 

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As I stated above, I thought the title of this thread had something to do with corner speed.
Horsepower is irrelevant! It's physics!
Under ideal conditions, on a curving smooth flat surface, equal tires - An object with less mass
(250 vs 600, 600 vs 1000) will exert less force onto the the tire's footprint.
This naturally allows the tire on the lighter machine to provide more grip, traction, speed.
Although the smaller bike may be fitted with a correspondingly smaller tire size, the actual contact patch
will not be significantly smaller to affect a difference here.

Haven't seen too many Ninja 250s lately wearing top shelf tread, or wearing riders capable of exploiting them.

Watch out for 250 two-strokes in the turns. Ask the MotoGP boys...
And if you're on a big, heavy machine, don't sleep on those 600SS's.
The can eat you in the twisties.

This dead horse has been beat.
 

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what R you lookin' at?
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agreed, corner speed is about traction and weight, cornering is all physics boy's...........not hp.
 

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What about the gyroscopic effects?

I thought part of the reason a 250 could out corner larger bikes is because of the fact that there is less of a gyroscopic effect from the motor.

Also, 250's have much smaller wheels and tires which also have less of a gyroscopic effect.
 

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I remember watching the roadraces here in Topeka several years back. There was an EX500 and Honda 600 Hurricane going at it. Evertime thru the infield the the guy on the EX would just run off and leave the Honda. Down the strait away though the Honda would out accellerate the EX. After several laps the EX had enuf lead coming out onto the strait way the Honda couldn't catch him anymore. Both would good riders just the EX was easier to handle in the infield sections....
 

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One more thing, what effect does tire size have on cornering?

125gp bikes are susposed to be the best cornering bikes ever. Their rear tires are 120mm wide I believe, vs 180mm wide on a 600ss. Can a 125 go around a given corner, at a faster given speed than a 600 because of the narrower tire or is it solely due to the lighter weight of the 125. I would think that since the smaller rear tire offers such a small contact patch, a 125 rider would still have to be pretty careful when cornering. Also, does the narrower tire allow the bike to fall into corners faster or something as well?
 

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Mad Max said:
What about the gyroscopic effects?

I thought part of the reason a 250 could out corner larger bikes is because of the fact that there is less of a gyroscopic effect from the motor.

Also, 250's have much smaller wheels and tires which also have less of a gyroscopic effect.
Ahhh, we delve deeper... Two strokes and smaller 4 strokes have less internal rotating mass in general.
Gyroscopic effect comes in to play primarily when we make side to side transitions... in the essess and chicanes!
Look at the new ZX10R...
Same weight as the 600SS bikes. But it's crankshaft is much heavier and has far greater inertia,
or gyroscopic effect. Oh yeah, it's flickable! Just not as much as it's 600SS league weight would have you think!

On to smaller wheels, tires and brakes.
Brakes make up a large portion of unsprung weight and rotational inertia.
Not to bore you with mathmatical formulas here, but as that additional wheel weight rotates it gains significant inertia.
This 'gyroscopic' effect coupled with larger width wheels and heavier tires will cause a noticeable
slowdown in side to side handling. Along with slower braking and acceleration to some extent.
The Honda 954 had HUGE rotors. Where are they now on the latest SS bikes?
Gone! Replaced by more efficient radial mount calipers on smaller rotors.

The smaller wheels and tires on 250 and 125 GP bikes do not hinder lateral grip at operating lean angles at all!
The contact patch, when leaned over , is quite similar between a 140 series and a 190.
The larger tire offers a larger patch and more grip under power when standing upright.

In summary, the lighter bikes have an inherent advantage in a curve.
With two bikes of equal mass, the one with less gyroscopic intertia will have the advantage in side to side chacane transitions.

Look at the GSXR750 whoop up on the literbikes on tighter tracks. And 600s too!

Sorry for the Blog! Kevin Cameron is one of my heros. :headbang
 

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i would agree that the 250 would smoke the 600. physics is physics....however, when the 4-stroke gp bikes went one on one w/the 500 strokers, even though the 500 was much lighter, the 4-strokes kept up fairly well in the corners. but i believe that's possibly due to higher entry speed.
 

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Just check out the average and best lap times for MotoGP. The 250cc is usually within 4 seconds of MotoGP class.

Also, the true 250gp bikes (my bike is NOT a TRUE GP bike) they weigh in at around 215lbs dry and have 100hp. That's a much better power/weight ratio than the stock 600's out there. But then again the 250gp bikes are true race bikes. That's why once I get my Yamaha TZ250, I'm gonna OWN trackdays :flipa
 

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Mmm... some things don't look right here. Common physics misconceptions being perpuated.

What effects cornering speed?

1. Non-rotating weight - NO. Turning is all about applying a lateral force to change direction. With static friction, available lateral force is EXACTLY proportional to the force applied perpendicularly to the surface. Since the lateral force required to turn a bike is proportional to its weight, it cancels out exactly. A bike of any weight on a given type of tire will lowside at EXACTLY the same lean angle.

2. Rotating weight - YES. firefighter explained it really well. It doesn't seem like this should make a huge difference, but I don't have the numbers or experience to back that up.

3. Contact patch - NO. It's just not in the equations, sorry. B***** tires exist for reasons like not overheating as easily, not wearing out as fast, and not deforming under extreme stress. They also look cool.

4. Type of surface and tire - YES. This is the one true limit to how fast something can accelerate (speed up, slow down, or turn), and yet it's the factor most ignored in magazine reviews.

5. Suspension - NO. It would certainly make a difference in rapid maneuvers (like quick S-curves), but not in sweeping turns.

This is all on paper, feel free to counter that it doesn't work that way in the real world. Just don't go around backing up your opinions with "it's just physics" when it's really just a runaway meme.
 

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there are clearly a lot of physicists here and not so many racers.
You can calculate all day, but the bike which carries more corner speed is the one with the best setup.
weight is irrelevant here, it's all about chassis geometry and setup...
 

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ok, but presuming both bikes had the same geometry/set up and they had the same entry speed, the 250 will still have faster corner speed.
 

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Why would a 600 have a faster entry speed? Wouldn't he have to get on the brakes more so than the guy on the 250? Unless I'm completely wrong in what entry speed is.
 

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One of the reasons 250's have better corner speeds is the tyre sizes...larger bikes have wider rears, which steps out the back end and makes them less stable at lean. This is why superbikes are ridden more with a brake/square-off/stand up and throttle-out technique. The similar (or identical) size tyres on the front and rear of the 250's makes them a better prospect for big lean angles and corner speeds, as they don't have the monster power outputs to put to ground.

EDIT: when i say "250", i mean 250gp bikes, etc, not learner-intended POS's.
 
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