Road course tire wear question-

Discussion in 'Suspension and Chassis' started by Drlee50, Aug 21, 2018.

  1. Drlee50

    Drlee50 TMO Race

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    I ran putnam park on sticker Continental g5000 tires. 285s on a 10" rims, square.
    The camber up front is -2.2 or -2.3 degrees up front. This track runs clockwise and is known to be hard on the drivers front tire .

    It was my first time at this track and the first 2 or 3 sessions I got it sorted out and it was hard laps for 2 more session on day 1 and 5 hard sessions on day 2. I did not rotate tires at all. Temps were within 5 degrees across the inner, middle and outer treads with the inner being the warmest ( front and rear ! )
    Upon close inspection of all 4 tires I can say the rear and the drivers front all wore pretty damn even across the wear indicators. The passenger front wore the inside tread all the way down so the dimple tread indicator is now gone. My toe is zero. Max caster, but even .

    What does that mean? Car felt planted pretty well. I do push it to the grip limits. I can occasionally feel the rear want to drift just a bit. I don't feel any push through the corners.

    Suspension is stock shocks with some ford springs that are a tiny bit lower and tiny bit stiffer than stock. Stock sway bars. Rear has Boss 302s lower control arms and the variable 3 position rear mounts. I was running the arms in the lowest spot . that put then at about a 9 degree angle. I am headed to mid ohio in a week and a half and i moved them to the middle hole which is about 4 degree tilt.

    What does this wear indicate and how can I fix it ?
    Thanks TMO!


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  2. Drlee50

    Drlee50 TMO Race

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    Note - I have some scales and This is with me in the car :
    Oink[​IMG][​IMG]

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  3. Drlee50

    Drlee50 TMO Race

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    anyone have any ideas here? excess tire wear on the passenger front inside tread- on a clockwise track.
     
  4. VoodooBoss

    VoodooBoss Rick Moderator

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    Too much camber for that track?
     
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  5. Norm Peterson

    Norm Peterson Corner Barstool Sitter

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    Even wear on the outside front suggests that camber isn't too far off. Perhaps the street-softish suspension is allowing too much roll from grip that's somewhere above street tire levels and the RF is getting pulled a little too far negative. Maybe there's a touch too much static toe-out?


    Norm
     
  6. 06mach1

    06mach1 TMO Addict

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    Sounds like too much camber on the right front for that track. Did you take tire temps right away or was it possible they cooled off before you checked them. If the front right tires temps on the inside was hotter than the outside, you had too much camber putting a load on the inside of the tire.
     
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  7. Grant 302

    Grant 302 OPM Spent: $665,833 Moderator

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    My guess is the opposite. Not enough toe out when the driver side is loaded. Perhaps also a little too much camber on the passenger side as noted by others.

    Depends if you feel there is something to 'fix'. The possible solutions include simply rotating your tires since you have a square setup. This is *exactly* why some people run square.

    If you want to approach it from a front geometry change, then you could be looking at *several* adjustments to make it 'right' for that track. My understanding is that while the passenger tire is nearly unloaded, it is contacting on just the inboard side and scrubbing laterally compared to the turn radius from the loaded driver tire. Back to my guess- not enough Ackerman resulting in less dynamic toe out.

    Possible settings to change:
    More static toe out
    Less passenger camber
    Less overall camber
    Springs and/or ride height
    Tall ball joints

    Depends how you'd want to approach it.

    My apologies for not posting earlier...I was thinking about your issue yesterday morning and got a little sidetracked.
     
  8. Drlee50

    Drlee50 TMO Race

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    I really appreciate the help guys. I was thinking since the drivers side was good that the camber was ok. Other thinks are at place besides camber when assessed dynamically so that's why I asked you pros! The drivers outside does have some wear as expected, so i dont want to reduce camber on that side. I will reduce passenger side. What do you think- .5 degrees to start? Im at 2.2 and can easily set up anything between 1.2 and 2.2.
    I thinking 1.7 and see what it does. [​IMG][​IMG][​IMG][​IMG]

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  9. VoodooBoss

    VoodooBoss Rick Moderator

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  10. Grant 302

    Grant 302 OPM Spent: $665,833 Moderator

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    That and another lb. or two of pressure hot in the fronts and rotate.

    Hard to tell from the pics, but are the centers on both showing a bit less wear?
     
  11. Drlee50

    Drlee50 TMO Race

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    Yes both are a tad less wore in the center tread.

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  12. Grant 302

    Grant 302 OPM Spent: $665,833 Moderator

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    A couple more pounds hot should help with that and roll over less.
     
  13. Drlee50

    Drlee50 TMO Race

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    Will do! Thanks a bunch !!!

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  14. blacksheep-1

    blacksheep-1 TMO Addict

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    Looks to me that the tire is wearing the inside down the straights, then wearing the outside in the corners, so..yes..a couple of psi would probably help in this case..plus maybe a bit less camber..not much, because you're gonna want it back at mid Ohio... Mustangs notoriously push corner center, so you may just have to concentrate getting it into and out of the corner and leave the mid corner hero driving to the Miatas (i hate miatas). Here's a vid from a few years ago, I'm not sure who's driving, AJ or Kurt, I'm sure,.. and it looks like Contis, so I'm going to assume it's the IMSA GS car, or maybe a T1 car..but the important thing is to look at what the tire is doing in the corners, the tire is going from having sunlight under the outside edge to having the center of the wheel trying to push itself through the tire, as the car goes through the corners, this is why depending on tire temps by themselves can be misleading, because the center of the tire is rarely used. You also didn't mention how the temps were taken, what they were, or how long it was after the car came off track, or the hot pressures...all that figures in to this.



     
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  15. Drlee50

    Drlee50 TMO Race

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    Thanks for the help !!!
    I'll see if i can add some info-
    Temps are taken as quickly as i can get my harness off. I just out with my longacer laser perimeter and i measure the center, inside and outside temps. Then I check the tire pressure hot

    Tire pressures are right at 31 psi each on G5000 Continentals.
    The temps are always warmest on the inside and cooler on the outside
    Inside fronts- 135 to 140
    Center- 130 to 135
    Outside - 125 to 130
    Always a 8 to 10 degree spread , warmest inside.
    The rears are always 10 degrees warmer than the fronts. They also are warmer on the inside tread with closer to a 5 degree spread. 145 outside, 150 inside and 147 center.

    For mid o, should I just reduce camber on passenger side only?

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  16. blacksheep-1

    blacksheep-1 TMO Addict

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    OK, FWIW the IR guns are notoriously inacurate, the probes are much better, the Contis that we run have been as high as 220 on the inside without a huge degradation of the tire. and 20 degree spreads are no big deal. I would leave the camber alone as I think you are going to want it at Mid Ohio. also as I recall, MO will punish the driver's side more than the passenger side, so you should be fine with what you have. Looking at some of my old notes, I would throw a couple of psi at it and see what happens. It also appears that those tires are getting pretty tired, we would've discarded them awhile back, basically 3 heat cycles, and they are warmup only tires.
     
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  17. Drlee50

    Drlee50 TMO Race

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    I'll try those changes and report back. Those tires were used for 7 sessions total from being sticker new. 5 sessions were me pushing for best lap times each lap after 1 or 2 warm up laps. The rears are less wore. I have 4 that are less wore and those those 2 are my most worn. Hopefully the 6 tires will last this next 3 day weekend before they are retired. I'll try to be a but more gentle on them in the corners as you suggested.
    Thanks a bunch !!!

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  18. blacksheep-1

    blacksheep-1 TMO Addict

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    Put the best on the front, mustangs tend to push
     
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  19. RodS197

    RodS197 TMO Intermediate

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    I have seen the inside of an R1 front tire chorded in a day (not my car, I couldn't afford R1 tires back then...) as a result of a loose front control arm busing bolt. Also, if the car has the hydro bushings on it, it will induce toe out under hard braking. You have many other expert voices giving you great advice so I would listen to them first, it was just that your tire wear brought back a memory!

    Bump steer could be an issue as well.

    After some odd front tire wear early in my driving, I mounted a camera on my control arm and did some hard braking runs. After seeing the deflection in the hydro bushing, I went to a Prothane unit. Much more better as they say.

    Here is the video for those interested.

     
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  20. Coz

    Coz TMO Race

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    What exactly was your "odd tire wear?"
     

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