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Discussion Starter #1
In regards to cornering and turning how much difference would 24.5/4.0" rake/trail on the 2019 vs 24/3.9" on the 2020 make for turn in with both sporting a 190/50 rear tire? Does half a degree in rake and 1/10th inch of trail really matter all else being equal?

Would the difference be as drastic as adding a 190/55 rear to the older models?
 

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I have no experience in comparing the different tires sizes. As for the change in the rake/trail, my answer would be yes/no. some will say it is a major improvement and others will say it is a minor improvement. It does make a difference but to what degree only the masses who have direct experience with both can determine for themselves. I think the 2020 probably turns in a bit easier/faster than previous year models, but it does not have neutral in lean in my opinion. As for how it compares, others with experience would be better to give their opinions.
 

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Discussion Starter #3
I have the 190/55 on my 15 and would like to ride a 2020 for comparison. The 190/55 made a fairly significant difference IMO.
 
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I have the 190/55 on my 15 and would like to ride a 2020 for comparison. The 190/55 made a fairly significant difference IMO.
What is the significant difference? Effort to get it leaned or effort to keep it at lean, or both? Are you using the same body position and is the difference you mention primarily in counter steering or weight shifting?
 

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Discussion Starter #5
Effort to get leaned for sure. I am using the same body position I used before switching rear tires. I am trying to get in the habit of leaning my upper body into the direction of the lean more.

I'm not a very experienced rider and am watching a lot of videos and trying different methods presented in the videos.

Having said that, the difference I experience is primarily in countersteering at this point.
 
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I pretty much gave up on trying to predict steering geometry because of my dirt bike. One somewhat popular mod, on the yz 250, was a new set of triple clamps. All these clamps did was move the forks backwards, in relation to the steering head. That measurement is called "offset", or triple clamp offset. I changed from 24mm stock, to 22. Pretty much nothing.

The bike steered faster, as expected, but it was also more stable. Very strange, and not expected due to the faster steering. Kawasakis change ? There might be a better way to guess if we knew exactly how they make the change, or even if they did. A slightly shorter fork would change your numbers to match the new bikes. You can try this by sliding the fork tube "up" in relation to the triple clamp. It should have room to slide up 7-8 mm . People have done this and been happy with the change on the older bike.
 

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Interesting question! It seems like some trigonometry should give a definitive answer. Unfortunately I couldn't find the right kind of calculator online and I'm not great at trig.

I banged around on the math a little bit, starting with the presumption that a 190/55 lifts the tail of the Ninja by approx. 10mm relative to the stock 190/50. How much does that 10mm alter the 25.5 degrees of rake on the 2019 fork? I'm not totally sold on my math (never liked story problems), but my sketch calculations suggest that the switch to a 24 degree rake on the 2020 is a more pronounced change to the steering geometry than what is being achieved by switching to a 190/55 tire on the 2019. I think the 190/55 tire change alone is probably worth less than 0.1 degrees of rake, rather than the 0.5 degrees of rake reduction in the 2020.

I don't know how much I'd trust any of that, but I guess I'd go with a final answer that I would expect the 2020 geometry changes to be at least as substantial as what could be achieved by the 190/55 tire.
 

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Discussion Starter #8
Interesting question! It seems like some trigonometry should give a definitive answer. Unfortunately I couldn't find the right kind of calculator online and I'm not great at trig.

I banged around on the math a little bit, starting with the presumption that a 190/55 lifts the tail of the Ninja by approx. 10mm relative to the stock 190/50. How much does that 10mm alter the 25.5 degrees of rake on the 2019 fork? I'm not totally sold on my math (never liked story problems), but my sketch calculations suggest that the switch to a 24 degree rake on the 2020 is a more pronounced change to the steering geometry than what is being achieved by switching to a 190/55 tire on the 2019. I think the 190/55 tire change alone is probably worth less than 0.1 degrees of rake, rather than the 0.5 degrees of rake reduction in the 2020.

I don't know how much I'd trust any of that, but I guess I'd go with a final answer that I would expect the 2020 geometry changes to be at least as substantial as what could be achieved by the 190/55 tire.
If you're right that is a significant difference. Wish they'd do a demo day nearby sometime.
 

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The difference is this:

Stock Tires: Bike flicks into corners pretty quick. Steering is light. But it as soon as you ease up on handlebar pressure the bike changes its line and begins to straighten out. So if you're negotiating back to back switchbacks, you won't notice it much because you're constantly changing directions. But as soon as you negotiate a long, smooth arc, especially if it's just a gentle arcing turn, you will notice you MUST keep pressure on the bars to maintain your chosen line.

Neutral steering feels like this: put pressure on bars to lean one direction. Ease up on the pressure and bike remains in that lean angle. Need opposite pressure on the bars to straight bike out.

The Neutral steering is better. It makes riding twisties easier. It relaxes your brain and your muscles because you can flick bike into corner and leave it there until you're ready to change direction.
 

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Another way to get some opinions is to read the reviews on the 20N1K in the bike rags. There are many but at least three that I read were from those familiar with previous model years that reported the hard steering input had been addressed and fixed by the rake/trail changes on the 2020. I think 'fixed' is also relative and I don't know these folks from Adam. My personal experience is it goes into the corners OK, but needs pressure to stay there. The only thing I have to compared it to is my ZX14r and that bike steers better than the N1K.
 

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Discussion Starter #11
Yeah, seems most of the magazine reviews tend to put a positive spin on nearly everything. I'd like to read reviews from owners of the new and old bikes.
 

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Interesting question! It seems like some trigonometry should give a definitive answer. Unfortunately I couldn't find the right kind of calculator online and I'm not great at trig.

I banged around on the math a little bit, starting with the presumption that a 190/55 lifts the tail of the Ninja by approx. 10mm relative to the stock 190/50. How much does that 10mm alter the 25.5 degrees of rake on the 2019 fork? I'm not totally sold on my math (never liked story problems), but my sketch calculations suggest that the switch to a 24 degree rake on the 2020 is a more pronounced change to the steering geometry than what is being achieved by switching to a 190/55 tire on the 2019. I think the 190/55 tire change alone is probably worth less than 0.1 degrees of rake, rather than the 0.5 degrees of rake reduction in the 2020.

I don't know how much I'd trust any of that, but I guess I'd go with a final answer that I would expect the 2020 geometry changes to be at least as substantial as what could be achieved by the 190/55 tire.
29970


The black triangle T-A-B represents the stylized frame of a N1K, where A is at the steering head and T is the front wheel axle and the wheel base is WZ

By definition, the steering angle is X-T-W, , and if we extend the line X-T-A to an imagenary point C, we create a 90* right-angle triangle. It can be shown that the angle X-T-W is the same as C-A-K.

If we raise the rear of the frame, point B which is directly above the rear axle, the frame will rotate around the front wheel axle to point M, and point C will rotate to point H, and the steering angle will change to P-T-W.

We know, from the published N1K specifications, that on the 2017~19 N1K, this angle . . . . (X-T-W) is 24.5* while on the 2020 it is 24*, a reduction 0.5* degrees.

So to achieve a 0.5* reduction in steering angle on a 2017~19, we need to determine the distance SB.

We know that the wheelbase (WZ) is fixed at 1440mm on both the 2019 & 2020 N1Ks.

So if you remember your high-school trigonometry, SB can be determined by the equation

The Tangent of the angle BRS = SB/1440.

Now, we know that angle BRS = 0.5*, so SB =1440 x tan(0.5). Punch those numbers into your phone's calculator and you get SB = 12.566mm.

Compare this result to the theoretical increase in height by going from a 190x50 to a 190x55 which is 9.5mm.
 

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Discussion Starter #13
View attachment 29970

The black triangle T-A-B represents the stylized frame of a N1K, where A is at the steering head and T is the front wheel axle and the wheel base is WZ

By definition, the steering angle is X-T-W, , and if we extend the line X-T-A to an imagenary point C, we create a 90* right-angle triangle. It can be shown that the angle X-T-W is the same as C-A-K.

If we raise the rear of the frame, point B which is directly above the rear axle, the frame will rotate around the front wheel axle to point M, and point C will rotate to point H, and the steering angle will change to P-T-W.

We know, from the published N1K specifications, that on the 2017~19 N1K, this angle . . . . (X-T-W) is 24.5* while on the 2020 it is 24*, a reduction 0.5* degrees.

So to achieve a 0.5* reduction in steering angle on a 2017~19, we need to determine the distance SB.

We know that the wheelbase (WZ) is fixed at 1440mm on both the 2019 & 2020 N1Ks.

So if you remember your high-school trigonometry, SB can be determined by the equation

The Tangent of the angle BRS = SB/1440.

Now, we know that angle BRS = 0.5*, so SB =1440 x tan(0.5). Punch those numbers into your phone's calculator and you get SB = 12.566mm.

Compare this result to the theoretical increase in height by going from a 190x50 to a 190x55 which is 9.5mm.
That's exactly what I thought! 😆
 
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Having owned a 2011 and now a 2020, I can tell you it is a big difference.
 

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Discussion Starter #16
Having owned a 2011 and now a 2020, I can tell you it is a big difference.
Would you say not necessary for a 190/55 rear on the nee one?
 

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View attachment 29970

The black triangle T-A-B represents the stylized frame of a N1K, where A is at the steering head and T is the front wheel axle and the wheel base is WZ

By definition, the steering angle is X-T-W, , and if we extend the line X-T-A to an imagenary point C, we create a 90* right-angle triangle. It can be shown that the angle X-T-W is the same as C-A-K.

If we raise the rear of the frame, point B which is directly above the rear axle, the frame will rotate around the front wheel axle to point M, and point C will rotate to point H, and the steering angle will change to P-T-W.

We know, from the published N1K specifications, that on the 2017~19 N1K, this angle . . . . (X-T-W) is 24.5* while on the 2020 it is 24*, a reduction 0.5* degrees.

So to achieve a 0.5* reduction in steering angle on a 2017~19, we need to determine the distance SB.

We know that the wheelbase (WZ) is fixed at 1440mm on both the 2019 & 2020 N1Ks.

So if you remember your high-school trigonometry, SB can be determined by the equation

The Tangent of the angle BRS = SB/1440.

Now, we know that angle BRS = 0.5*, so SB =1440 x tan(0.5). Punch those numbers into your phone's calculator and you get SB = 12.566mm.

Compare this result to the theoretical increase in height by going from a 190x50 to a 190x55 which is 9.5mm.
You lost me at T-A-B & I definitely should have listened more in school 😂
 

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Discussion Starter #18
He lost me at "The"
 

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Murph you're a peach.
I would say simply though, that the 55 on back closely approximates the change in rake between the old bike and the new bike with stock tires. Decreasing rake sharpens the steering.
Also, while I didn't ride the 2020 last saturday (I was at a demo day) I sat on it. The bars seemed higher and wider. Likely why the screen had to change. Higher and/or wider bars would add more steering leverage.
 
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