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Good !
I remember that the S22s front was smaller than the rear.
Your measurements show that this difference would even be larger with the Cup2s !
It would be interesting if you could mesure the difference in the bike geometry : having a look at where the O-rings on your forks stand will give you an idea.
I had the S22s installed not too long ago and I have not felt major differences yet as I am not pushing the bike at this time (too cold here ...) + I am no Quartararo ...
Love these tires, have them on the Duc as well, easy to get rid of the cs :)
 

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I only have anecdotal observations based on the o ring since I’ve never measured full travel previously, but I’ll keep an eye out.

My precise measurements were:

S22
Front 1,880mm circumferenceradius 299.2mm (1mm taller than PC2)
Rear 1,966mm, radius 312.9mm (4.5mm lower than PC2)

PC2
Front 1,873mm, radius 298.1mm
Rear 1,994mm, radius 317.35mm

So the fronts are basically the same height from the ground and the feeling difference can be attributed to the more aggressively peaky profile of the S22. But when combined with the 4.5mm lower rear ride height, the net effect is the chassis rotated 5.5mm upward at the front (more stable, more steering effort),

I can either drop the front 1 line (I think that gives me 4mm back), increase preload in the rear a lot (has other negative effects), or a combination of both.

I didn’t notice a change between the PC2 and Power GP so I wonder if the whole Power family shares the same profile and dimensions. If so I will probably go with Power 5’s for street use and PC2 for the track and not have to mess with this.
 

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2021 KTM Duke 890R
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I believe as tires age there is a cycle of the changing bike geometry. I remember running road 5’s on sv650 and by the time rear tire wore out after 5-7 thousand miles. A brand new set of tires flicked thru the corners much easier. So setting the suspension up to work the best most of the time is the best we can do. I have run a softer front tire of the same tire family to have better grip on the front and have the tire wear out at a closer rate to the rear. Then I could change them out in pairs.
 

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Sure, mileage will square a tire off in the middle, which definitely affects handling and feel compared to a fresh set. And yeah like you said I've been running a PC2 front with either a Power GP rear for street or PC2 rear for track and it's been lasting through 2 rears. I swapped to the S22s mainly because I had a crash on cold and wet roads and wanted something more street oriented, but kept the Michelins for warmer days as they're not worn much.
 

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Tires expand when rotating - I’m willing to bet that among tires the amount they expand deviates more than your static deviation.
I’m also very suspect of the idea that 4.5mm would have any perceived impact on handling or gearing for that matter.

If this thread gets more scientific and less speculative I’ll grab the popcorn!
 

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Tires expand when rotating - I’m willing to bet that among tires the amount they expand deviates more than your static deviation.
I’m also very suspect of the idea that 4.5mm would have any perceived impact on handling or gearing for that matter.

If this thread gets more scientific and less speculative I’ll grab the popcorn!
Lowering Your Bike Safely - The Long and Short of It --> "Changing the front or rear ride heights by as little as 5mm can have a dramatic effect on how a bike handles in the corners"

On a bike as sharp steering as the Duke 890R I think chassis geometry changes are much more noticeable than if you made a 5mm ride height change on a big and heavy bagger or something like that.

I never said anything about gearing. I agree that impact would be negligible unless you drastically changed tire or wheel sizes.
 

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“As little as 5”— but your deviation is less than that. I’m just not sold that it would be perceived by vast majority of riders.
1.1mm taller in front + 4.5mm lower in rear = 5.6mm total change in chassis attitude.

Anyways I feel like we're going down a weird path. All I tried to ask is if people had suggestions for doing ride height changes with the stock suspension, I don't want to spend all night trying to convince you that I felt a noticeable change in the handling after putting the new tires on.
 

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6 mm will definitely make a difference; I know as I did lower the forks on one of my old bikes and even me could feel it !
I don't think there is any easy solution to modify the ride height on the 890R. In my case - because I am so lightweight - I changed the springs rear and front and added preload ajustment on the forks; I could alter the geometry by adjusting the sag and I am now able to use most of the travel on the front.
These extra parts are the same you find on the WP Apex Pro 6500.
On a final note, here are Dave Moss' measurements; he has larger figures for the rear tires : it is not an easy task, better rely on comparative measurements on the bike, using a spirit level.

Rectangle Font Number Screenshot Circle
 

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I have run around a dozen sets of these on several different bikes. Began with the S21 and now the S22. My all time favorite tire.

Best bargain out there. Priced considerable less than many other brands and give up nothing regarding performance. I get a solid 3500 miles from a set and my mostly in the twisties riding style has them wearing very evenly.

I was just reading the last few posts about tire diameter and ride height. I did not notice any difference from the stock tires in terms of handling. Perhaps I am not as sensitive as some are. If this is a bother the remedy is an easy. Half a turn on rear preload or raising the forks a few mm should solve the problem.
 

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I have run around a dozen sets of these on several different bikes. Began with the S21 and now the S22. My all time favorite tire.

Best bargain out there. Priced considerable less than many other brands and give up nothing regarding performance. I get a solid 3500 miles from a set and my mostly in the twisties riding style has them wearing very evenly.

I was just reading the last few posts about tire diameter and ride height. I did not notice any difference from the stock tires in terms of handling. Perhaps I am not as sensitive as some are. If this is a bother the remedy is an easy. Half a turn on rear preload or raising the forks a few mm should solve the problem.
Yes they're a great value, and I like the feel of them a lot so far in my limited experience on them. When they're on sale they're like 1/3 the cost of a set of Michelins, so I'd love to get the bike set up to work with them and then ride off happy and saving some money. :)
 

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I only have anecdotal observations based on the o ring since I’ve never measured full travel previously, but I’ll keep an eye out.

My precise measurements were:

S22
Front 1,880mm circumferenceradius 299.2mm (1mm taller than PC2)
Rear 1,966mm, radius 312.9mm (4.5mm lower than PC2)

PC2
Front 1,873mm, radius 298.1mm
Rear 1,994mm, radius 317.35mm

So the fronts are basically the same height from the ground and the feeling difference can be attributed to the more aggressively peaky profile of the S22. But when combined with the 4.5mm lower rear ride height, the net effect is the chassis rotated 5.5mm upward at the front (more stable, more steering effort),

I can either drop the front 1 line (I think that gives me 4mm back), increase preload in the rear a lot (has other negative effects), or a combination of both.

I didn’t notice a change between the PC2 and Power GP so I wonder if the whole Power family shares the same profile and dimensions. If so I will probably go with Power 5’s for street use and PC2 for the track and not have to mess with this.
I decided to check the sag the other day and was shocked to discover the rather large amount both front and rear. Front was 59mm and rear was 56mm. This was with all riding gear on.

Left the front alone as there are no adjusters, unless you want to remove the forks and add a couple of pre-load shims. Nah too much work.

So I decided to add a notch of pre-load to the rear. This made a very noticeable difference in steering, restoring the razor sharp precision the bike had with stock diameter tires.

Thanks for posting this Fred. Made me fall in love with my bike all over again.

Heck I might just get some flowers and a box of chocolates for the bike on the 14th. ;)
 

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Sag on this bike, especially on the forks, is significantly higher than what you are used to on sport bikes. Even after rebuild and spring swap for my weight, I was still getting high 40's low 50's. Couldn't dial it to the "usual" numbers.

That said, fork stroke (travel) is ~160mm (see K-Tech pdf attached). Going with 25%-30% or even 33% of stroke for rider sag, will give you 40mm-48mm (up to 53mm in taking 33%).
 

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Sag on this bike, especially on the forks, is significantly higher than what you are used to on sport bikes. Even after rebuild and spring swap for my weight, I was still getting high 40's low 50's. Couldn't dial it to the "usual" numbers.

That said, fork stroke (travel) is ~160mm (see K-Tech pdf attached). Going with 25%-30% or even 33% of stroke for rider sag, will give you 40mm-48mm (up to 53mm in taking 33%).
I was thinking that too as the suspension travel is a bit more than the sport bikes. I remember my dirt bikes with all their travel and associated big rider sag numbers.
 

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I was thinking that too as the suspension travel is a bit more than the sport bikes. I remember my dirt bikes with all their travel and associated big rider sag numbers.
Exactly. I can tell you that the numbers work well for me, even on the track. I am not running out of travel even with very hard braking. Just need to get used to how the bike shifts weight. Definitely a different experience than pure sport bikes.
 
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So I have an update and weirdness that I'm hoping someone can diagnose.

1. To recap, I lowsided the bike and twisted the forks. Took everything apart and it came together easily - nothing bent. Smooth movement in the fork when installing the wheel.
2. Checked my suspension settings to confirm they were the same as what Dave Moss helped me with (Comp 10 clicks out from full hard, Rebound 11 clicks out from full hard).
2. Swapped out the crashed PC2 for new Bridgestone S22's and immediately hated the front end. Did a bunch of math and realized (I thought) that the problem was a v-shaped front tire + a smaller rear tire making the front too tall.
3. Swapped the S22's for Michelin Power 5. Measured and compared to the PC2 and confirmed they are effectively the same profile and dimensions, so the bike should feel back to normal now.

Well, the bike STILL felt like crap! Front feels like it's riding tall, top of the stroke, no weight transfer to the front under braking or turning, and as a result the forks feel like they're folding in on themselves and the bike just tucks into the corners and scares me. It's awful.

I took a ride with a friend (who I usually can match turn for turn) and he walked me all day. We swapped bikes and he confirmed the weird feeling.

So here's the weirdness. We stopped mid-ride and I dialed Compression out to 24 clicks from full hard (total range is 28), and after that the bike felt normal again. Immediately I could attack the corners, felt confident that the tire was biting, turn in was nice and secure. It definitely was bouncier than my normal setting but at least it worked fine. I was psyched but also confused. Compression damping plays in during braking and hitting bumps, but it shouldn't completely lock out the fork movements. Plus, the original settings have always worked great.

To test it I set Comp back to 10 out and did known loop near my house. Right away the front end was terrifying. I finished the loop, set comp to 24, and the same loop felt great.

All I can think is somehow the crash messed up the compression valving and I need to open it fully for the oil to flow. When it's set to a firmer settings it's like it's just riding the spring at the top of the stroke. Super weird.

Has anyone experienced anything like this?
 
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