Hitting tire to hard? Video added

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9secRR

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tire looks to be taking a beating. This is with 8.5 lbs. last picture the tire is getting abused.

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looks about right to me

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something that I find interesting is no one ever talks about the effective variable gear ratio the tire gives.

Under starting the radius to the CL of the axle to the ground is smaller when the tire deforms making a higher numerical effective gear ration (just numbers... like going from 4:1 to 5:1)

Then at speed the tire grows making the CL of the axle to the ground larger and making a lower numerical effective gear ration (just numbers... like going from 4:1 to 3:1)
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I just think its cool!
 
tire looks to be taking a beating. This is with 8.5 lbs. last picture the tire is getting abused.

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I’ll tell you what, I’d be happy to have a car with enough nuts to hit a big tire that hard. If you have good shocks you should be able to tune around it. But that tire looks like it’s working pretty good to me if it’s not bouncing off rebound. I might put 2 psi in it and retest.
 
Have you tired more air pressure? Shock settings? Ladder Bar or 4 link?
I did try .5 more at 9 and tire did the same.
I tightened up the front 2 clicks and 3 clicks on the rear shocks.
Ladder bar
I’ll tell you what, I’d be happy to have a car with enough nuts to hit a big tire that hard. If you have good shocks you should be able to tune around it. But that tire looks like it’s working pretty good to me if it’s not bouncing off rebound. I might put 2 psi in it and retest.
Brand new QA1’s and springs on all 4 corners.
Since the season is long over I’ll try more air next season.
Do you have video? All I’m getting is pictures. Video would be better.
Yes I have the vids. Give me a bit to get them on YT to paste over here
 
I have tried for many years to try and stop getting my slicks to hit that hard. Multiple 4 link changes, shock changes, tire psi, launch RPM. Any and all changes I could think of, I have tried. Long story short, I just let them hit the way they hit and it works and is consistent. I rotate my slicks side to side and inspect them every time I rotate them. If they outside of the slicks are wearing a lot more than the middle, I'd increase PSI. I have slowly but steadily added PSI to my slicks over the past few years. Hasn't stopped the tire from doing what your pics are showing. Mine may possibly be even worse. I run a stiff sidewall slick with a tube and that really helps. I would say if you are wearing the sidewalls out really quickly, then I would make a change. But based on the photo, I would send it. And if it works with 9 psi, run it. I run 8.5 myself with I believe to be the same size slick as you have. Just my 2 cents. But I wouldn't worry too much unless its causing you issues.

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10.5 stiff sidewall running tubes. 13.5lb cold. Usually close to 15 after pass. Mid to high 1.2 60.

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Check your tire's wear at the end of the season and see if it is wearing more on the outside than in the middle.
i do check tires on a regular basics.
I have tried for many years to try and stop getting my slicks to hit that hard. Multiple 4 link changes, shock changes, tire psi, launch RPM. Any and all changes I could think of, I have tried. Long story short, I just let them hit the way they hit and it works and is consistent. I rotate my slicks side to side and inspect them every time I rotate them. If they outside of the slicks are wearing a lot more than the middle, I'd increase PSI. I have slowly but steadily added PSI to my slicks over the past few years. Hasn't stopped the tire from doing what your pics are showing. Mine may possibly be even worse. I run a stiff sidewall slick with a tube and that really helps. I would say if you are wearing the sidewalls out really quickly, then I would make a change. But based on the photo, I would send it. And if it works with 9 psi, run it. I run 8.5 myself with I believe to be the same size slick as you have. Just my 2 cents. But I wouldn't worry too much unless its causing you issues.

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looks like the same as me. so far sidewalls are looking good. don't have to many passes on them but so far so good.
10.5 stiff sidewall running tubes. 13.5lb cold. Usually close to 15 after pass. Mid to high 1.2 60.

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i have never run tubes, more air is required with tubes?
 
i do check tires on a regular basics.

looks like the same as me. so far sidewalls are looking good. don't have to many passes on them but so far so good.

i have never run tubes, more air is required with tubes?
Not necessarily more air with tubes. He’s running smaller tire. So smaller tire wants more PSI. Tubes help support the sidewall. It may help with the bulge you’re seeing.
 

Is it acting up? The tire rolling over itself? Chattering? What is squishing the tire? Is the axle separating or weight transfer? If it’s the axle, tighten the extension a bit. Weight transfer, up the air pressure. It’s working well enough it’s trial and error time. How even is the tire mark?
 
Whats you ladder Bar angle at ride height?
i think it's at 1-2* down IIRC.
Is it acting up? The tire rolling over itself? Chattering? What is squishing the tire? Is the axle separating or weight transfer? If it’s the axle, tighten the extension a bit. Weight transfer, up the air pressure. It’s working well enough it’s trial and error time. How even is the tire mark?
no it's working great. not rolling over, no chatter. axle separating decent. tire mark is good. i'll post up the videos from the back where i took the pictures from.

i'm in the process of installing a anti roll bar. wheelie bars are next on my list.
 
That looks pretty good! I know two guys that have said putting an anti roll bar on was one of the best things they ever did.
 
Tom's car hit's pretty hard. but I do see some wrinkle.. I don't know specifics though.
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That looks pretty good! I know two guys that have said putting an anti roll bar on was one of the best things they ever did.
i have heard that as well. i have started on the anti roll bar install, hoping to have it done before the new year.
I an told three wrinkles on the sidewall is correct.
yes, that's what i have been told from a few racers
 
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