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Discussion Starter · #1 ·
4 sessions at CMP (Kershaw, SC) on SC1 rear, a fun right oriented track that was repaved last year known to be abrasive on tires.
Is this a PSI or suspension issue? Consistent mark all around. On SC2 the wear is much better. I ran SC1 rear as high as 31PSI but still did not get consistent wear, track temp was in 70s. What to change?

BTW the raised front edge on tire dots is just from acceleration. Talked to multiple suspension guys about it. It's also in the center of tire.

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I find the sc1 always has more weird wear than sc2 on the rear

You have more grip but its much softer than sc2
 

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Discussion Starter · #3 ·
I find the sc1 always has more weird wear than sc2 on the rear

You have more grip but its much softer than sc2
Are you saying I should not worry about it?
 

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That tire looks hot, what was track temp? Tire temp? Could be the riders right hand, he’s been known to blow motors. Might have to start learning to nurse the tires instead of take pics of them lmao!
 

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4 sessions at CMP (Kershaw, SC) on SC1 rear, a fun right oriented track that was repaved last year known to be abrasive on tires.
Is this a PSI or suspension issue? Consistent mark all around. On SC2 the wear is much better. I ran SC1 rear as high as 31PSI but still did not get consistent wear, track temp was in 70s. What to change?

BTW the raised front edge on tire dots is just from acceleration. Talked to multiple suspension guys about it. It's also in the center of tire.

View attachment 216859

View attachment 216858
Too early to tell anything

As is it looks fine
 

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Are you saying I should not worry about it?
Basically yes. Soft tires doing soft tire things. Thats why they wont clear up

That tire looks hot, what was track temp? Tire temp? Could be the riders right hand, he’s been known to blow motors. Might have to start learning to nurse the tires instead of take pics of them lmao!
So slow down on track??
 

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4 sessions at CMP (Kershaw, SC) on SC1 rear, a fun right oriented track that was repaved last year known to be abrasive on tires.
Is this a PSI or suspension issue? Consistent mark all around. On SC2 the wear is much better. I ran SC1 rear as high as 31PSI but still did not get consistent wear, track temp was in 70s. What to change?
Warm up the track.
And change your driving line, a bit more roundish line while trail braking, and later apex so you get the bike to turn more before apex. Then you can get on the throttle more linearily from the apex and a bit more slowly to pick up the bike.
Now you have too early apex, too late turn and fast pick up, and then too late and too hard on the throttle.
 

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Discussion Starter · #8 · (Edited)
Warm up the track.
And change your driving line, a bit more roundish line while trail braking, and later apex so you get the bike to turn more before apex. Then you can get on the throttle more linearily from the apex and a bit more slowly to pick up the bike.
Now you have too early apex, too late turn and fast pick up, and then too late and too hard on the throttle.
What do you mean by warm up the track? It started in 63F in the morning (ambient temp not pavement temp, sunny), 75F in afternoon.

I think you are onto something, 2nd time at this track, couple of sectors my line could be better. I do pick up the bike as fast as I can.
Do you have any graphs that show what a roundish line looks like? Do you mean a long arc line or a V line? I do point/shoot lines at some turns, long arc lines at other turns. But I prop should stick to the latter.

Are you thinking of blue or somewhere between red and blue line?

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Are you sure you simply don't have the TC turned up too high?
The edge is smooth up to the wear dot in the middle, with hard wear immediately after that on the shoulder. i.e. You need to be getting on the power earlier and smoother. Otherwise the tyre doesn't look too bad.
 

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What do you mean by warm up the track?
Use flamethrower or similar.
I think you are onto something, 2nd time at this track, couple of sectors my line could be better. I do pick up the bike as fast as I can.
Do you have any graphs that show what a roundish line looks like? Do you mean a long arc line or a V line? I do point/shoot lines at some turns, long arc lines at other turns. But I prop should stick to the latter.
Continuous transition.
At brake mark:
Brake pressure 100%
Between brake mark and apex:
Brake pressure decreases continuously from 100 to 0%, and lean angle increases continuously from 0 to 50 deg.
At apex:
Brake pressure 0%, lean angle 50 deg, Throttle 0%.
Between apex and exit point:
Throttle opening increases continuously from 0 to 100% and lean angle decreases continuously from 50 to 0 deg.

You can not do continuous transition between brake mark - apex - exit point, if you use straight V-line or round long arc line.

Your driving line always dictates how you can use brake and throttle.
If you want to change you brake or throttle usage, you must always first change your driving line.
 

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Discussion Starter · #11 ·
Your driving line always dictates how you can use brake and throttle.
If you want to change you brake or throttle usage, you must always first change your driving line.
Yes, throttle, brake are dictated by race line.
But you said in previous post to use a more roundish line. Can you elaborate on that based on lines posted in pic? Is a roundish line in between a v-line & long arc?
 

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Is a roundish line in between a v-line & long arc?
Yes.
Between brake mark and apex; driving line radius decreases continuously.
Between apex and exit point; driving line radius increases continuously.
 

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Discussion Starter · #13 ·
Yes.
Between brake mark and apex; driving line radius decreases continuously.
Between apex and exit point; driving line radius increases continuously.
What you said makes sense if there is no straightaway after the turn. If the there is, on a liter bike a squared off line will be faster.
The blue line below is considered roundish, which is what you are suggesting to use right? If not, could you mark a roundish line on the pic?

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What you said makes sense if there is no straightaway after the turn. If the there is, on a liter bike a squared off line will be faster.
Old traditional bs-legends are still alive...
Squared off line is never faster, it is even slower than V-line.
You use it only if you have two stroke era motogp bike with "uncotrollable" power spike.
 

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Discussion Starter · #15 ·
Squared off line is never faster, it is even slower than V-line.
Not here to debate that. Just using the pic as example so you can easily show what you mean by roundish line. You missed the core question.
 

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Not here to debate that. Just using the pic as example so you can easily show what you mean by roundish line. You missed the core question.

Is a roundish line in between a v-line & long arc?
Yes.
 

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Discussion Starter · #17 ·
Did you mean to say a spiral like line not roundish? Because the traditional line is roundish.
Spiral like baseline (white) below. This for a car line but could not find a better diagram:

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Did you mean to say a spiral like line not roundish? Because the traditional line is roundish.
Spiral like baseline (white) below. This for a car line but could not find a better diagram:
No. As you see, apex speed is very low as in V-line, and that is not good.
With traditional round line, not roundish, you would get max apex speed, but driving line is long and you can not get on the throttle until exit point. So that suits (only) for low powered (300cc or so) bikes or very hi speed (100-150 mph) corners where you do not need longitudinal traction after apex.
 

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Discussion Starter · #19 ·
No. As you see, apex speed is very low as in V-line, and that is not good.
With traditional round line, not roundish, you would get max apex speed, but driving line is long and you can not get on the throttle until exit point. So that suits (only) for low powered (300cc or so) bikes or very hi speed (100-150 mph) corners where you do not need longitudinal traction after apex.
But apex speed is only important in a standalone corner (no straights before or after it).
The time taken at a corner matters more for connected corners (straights before or after it). In above example, while baseline has a slower apex speed than geometric line, but time spent to go through it is less by .28sec. For race track laptimes matter more than apex speed.

You have yet to show what you mean by a roundish line, if it's not a long arch, spiral, or traditional line, what is it?
 

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But apex speed is only important in a standalone corner (no straights before or after it).
The time taken at a corner matters more for connected corners (straights before or after it).
For race track lap times matter more than apex speed.
Apex speed is always important. It does not mater if there is standalone corner or connected corners.
Apex speed dictates the max speed and average speed before corner, in the corner, and after the corner.
That is why lap time (average speed of a lap) is of a result of apex speeds.
At the same time you must make a optimal compromise between driving line length and apex speeds, where apex speed has bigger influence than driving line length.

V-line has short length but low apex speeds, and traditional round line has high apex speeds but long driving line. That is why the fastest line is a compromise between those two lines.
 
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