Tire wear?

[SonnyJack]

So in the interest of trying not to over think things I have a question on tire wear. The picture is two staggered tires from the driver's side, both facing the same direction.

The one on the right is the front (285). It is just starting to cord on the outside and all of the outside wear bars are gone. The opposite is true of the rear tire (295) which is just starting to cord on the inside with those wear bars faint but still visible.

From memory, camber is -3.6 front left and-3.4 front right and -2.4 degrees rear.

I'm moving to a squared 295/30-18 and curious if that really solves the problem. Seems like it should if the tires are rotated diagonally or front to back, just want to make sure I'm not missing something obvious. Side to side doesn't seem like it solves anything.

EDIT: Ignore that part about side to side not seeming like it does anything. My passenger side tires look like they came off a different car (picture with my foot holding the tire in place). All the wear bars are visible and while they are showing some signs of beginning to cord they are in much better shape then the driver's side tires.

EDIT #2 Tires are Hoosier R7's

TIA,
SJ

[Datka]

Are these BFG R1 or R1S tires. Softer compound requires more negative camber up front.
-3 F is not enough to run r-comp. tires on e9x m3.
If you have not checked your front/rear alignment for a while, you might have different numbers from the initial setting.
Moving tires from side to side makes no sense to me also, rotation should be diagonal and then front to rear and wise versa.

[SonnyJack]

Originally Posted by Datka

Are these BFG R1 or R1S tires. Softer compound requires more negative camber up front.
-3 F is not enough to run r-comp. tires on e9x m3.
If you have not checked your front/rear alignment for a while, you might have different numbers from the initial setting.
Moving tires from side to side makes no sense to me also, rotation should be diagonal and then front to rear and wise versa.

Sorry! I edited the original post again! The tires are Hoosier R7's. I'll look for my alignment specs again. Might be greater than -3 but not by much.

Alignment is -3.6 front left & - 3.4 front right

-2.4 in the rear

Appreciate your comments!

[DRLane]

Originally Posted by Datka

Are these BFG R1 or R1S tires. Softer compound requires more negative camber up front.
-3 F is not enough to run r-comp. tires on e9x m3.
If you have not checked your front/rear alignment for a while, you might have different numbers from the initial setting.
Moving tires from side to side makes no sense to me also, rotation should be diagonal and then front to rear and wise versa.

Side to side rotation is track dependent.

[tsk94]

By the sounds of it regular rotating once you're on a square setup will definitely help and even out the wear.

[SonnyJack]

Originally Posted by DRLane

Side to side rotation is track dependent.

Thank you!

Was actually just thinking this as these tires have seen multiple visits to VIR which has several hard right turns. There are also a few to the left but I'm thinking the left side is taking the brunt of it at that track. Also Summit Point, while shorter is again set up for more stress on the left side tires.

Appreciate your comments!

[dparm]

Surprised at that kind of wear given the alignment settings. Two questions, and please don't shoot me for asking:

1. What kind of driving technique do you use? How does the car feel? (understeery, neutral, oversteery)

2. How old are the other suspension components? I'm wondering if you're getting a lot of deflection from worn bearings and bushings which means your dynamic camber is crazy. What's the toe and caster?


It might be time to start flipping tires on the wheel after each day.

[SonnyJack]

Originally Posted by dparm

Surprised at that kind of wear given the alignment settings. Two questions, and please don't shoot me for asking:

1. What kind of driving technique do you use? How does the car feel? (understeery, neutral, oversteery)

2. How old are the other suspension components? I'm wondering if you're getting a lot of deflection from worn bearings and bushings which means your dynamic camber is crazy. What's the toe and caster?


It might be time to start flipping tires on the wheel after each day.

You're killing me Smalls!

I think you asked a great question and based on the tire wear I'm baffled! The car feels incredibly stable/neutral and tracks straight. Only at the very end of a session does it ever get what I would describe as "pushy" and I begin experiencing understeer. Not sure how I would describe my driving technique. How about give me a few options.....

Suspension components/bushings are all fairly new. At least new as in when the coilovers were installed four years ago August. Several rear components were swapped out during my extended stay at the shop last summer/fall/winter.

Alignment

Front
Camber -3.6L / -3.4R
Caster +7.2L / +7.3R
Toe -0.10L / -0.10R (toe OUT)

Rear
Camber -2.4L / -2.4R
Toe +0.20L / +0.20R (toe IN)

[tsk94]

Originally Posted by SonnyJack

You're killing me Smalls!

I think you asked a great question and based on the tire wear I'm baffled! The car feels incredibly stable/neutral and tracks straight. Only at the very end of a session does it ever get what I would describe as "pushy" and I begin experiencing understeer. Not sure how I would describe my driving technique. How about give me a few options.....

Suspension components/bushings are all fairly new. At least new as in when the coilovers were installed four years ago August. Several rear components were swapped out during my extended stay at the shop last summer/fall/winter.

Alignment

Front
Camber -3.6L / -3.4R
Caster +7.2L / +7.3R
Toe -0.10L / -0.10R (toe OUT)

Rear
Camber -2.4L / -2.4R
Toe +0.20L / +0.20R (toe IN)

Some more caster up front will help too.

Otherwise your alignment seems pretty standard for a track car.

[DRLane]

Originally Posted by SonnyJack

You're killing me Smalls!

I think you asked a great question and based on the tire wear I'm baffled! The car feels incredibly stable/neutral and tracks straight. Only at the very end of a session does it ever get what I would describe as "pushy" and I begin experiencing understeer. Not sure how I would describe my driving technique. How about give me a few options.....

Suspension components/bushings are all fairly new. At least new as in when the coilovers were installed four years ago August. Several rear components were swapped out during my extended stay at the shop last summer/fall/winter.

Alignment

Front
Camber -3.6L / -3.4R
Caster +7.2L / +7.3R
Toe -0.10L / -0.10R (toe OUT)

Rear
Camber -2.4L / -2.4R
Toe +0.20L / +0.20R (toe IN)

Note while desirable for turn in, the toe out on the front will wear the insides more aggressively. If you push the car mid corner inducing understeer you'll wear it even faster.

I'm back at 0 toe on the front, and it's significantly improved the inner wear.

[kayha12]

So my buddy just read up on Hoosier suggested tire pressures and basic maintenance of their A7/R7 tires. I was VERY surprised by their suggestions and may try it out next event.

They said you should start cold, no lower than 30 psi (30-34) and aim for hot pressures in the low 40s. Blatantly saying, if it feels like you're down on grip, don't lower the pressures.

I've always done cold 26-27, with a target around 34-36. And my tires will typically show premature out wear, front first, then rears. I went through my first set of stickers, and at 17 heat cycles they probably had maybe 5-8 more heat cycles before they chorded but I took them off. Take a look at their suggestions. Definitely worth playing around with it, especially if you're not competing. I have a feeling those running TT run lower pressures for that extra grip sacrificing tire life for the lap times

[SonnyJack]

Originally Posted by kayha12

So my buddy just read up on Hoosier suggested tire pressures and basic maintenance of their A7/R7 tires. I was VERY surprised by their suggestions and may try it out next event.

They said you should start cold, no lower than 30 psi (30-34) and aim for hot pressures in the low 40s. Blatantly saying, if it feels like you're down on grip, don't lower the pressures.

I've always done cold 26-27, with a target around 34-36. And my tires will typically show premature out wear, front first, then rears. I went through my first set of stickers, and at 17 heat cycles they probably had maybe 5-8 more heat cycles before they chorded but I took them off. Take a look at their suggestions. Definitely worth playing around with it, especially if you're not competing. I have a feeling those running TT run lower pressures for that extra grip sacrificing tire life for the lap times

Oh yeah! Before dropping 2k on a set of tires not designed to last long I checked up on tire pressures. I've been starting at 34-35 cold, as in first thing in the morning in the shade cold, and usually come off track around 42. I tried a lower starting pressure of 32 cold just once and the difference was very noticeable. Car was just soft in the corners.

[SonnyJack]

Originally Posted by DRLane

Note while desirable for turn in, the toe out on the front will wear the insides more aggressively. If you push the car mid corner inducing understeer you'll wear it even faster.

I'm back at 0 toe on the front, and it's significantly improved the inner wear.

As usual I wasn't clear in my initial post. In the first picture the wheel face is on the right for both tires, and the tire on the right is the driver's front and has worn on the outside not the inside.

[kayha12]

outside wear sometimes could be from premature rubbing, have you checked your fender liners and pinch welds? To run 295s I had to shave down the pinch weld closest to where the side skirt starts/ends. I smoked through my first set of 295 A7s from rubbing!

[SonnyJack]

Originally Posted by kayha12

outside wear sometimes could be from premature rubbing, have you checked your fender liners and pinch welds? To run 295s I had to shave down the pinch weld closest to where the side skirt starts/ends. I smoked through my first set of 295 A7s from rubbing!

No signs of rubbing on these tires which were 285 in the front. I appear to have room to run the 295's but will definitely check for rubbing. Thx!

[Datka]

Originally Posted by SonnyJack

Oh yeah! Before dropping 2k on a set of tires not designed to last long I checked up on tire pressures. I've been starting at 34-35 cold, as in first thing in the morning in the shade cold, and usually come off track around 42. I tried a lower starting pressure of 32 cold just once and the difference was very noticeable. Car was just soft in the corners.

Tire wear is affected by tire pressure, track surface, driving style, weight of the car, suspension set up, ambient temp, and many more factors I cant think of right now.
It looks like setting correct tire pressure is a thing of experimentation and individual preferences.
Personally, I have been running R comp. tires between 28 and 30 cold(depending on ambient and track surface temp)with -3.5F/-2.1R camber for a few years now and getting even wear all across that gives me max. tire life.
Your cold tire temp. seems way too high to be honest.

[dparm]

Originally Posted by SonnyJack

You're killing me Smalls!

I think you asked a great question and based on the tire wear I'm baffled! The car feels incredibly stable/neutral and tracks straight. Only at the very end of a session does it ever get what I would describe as "pushy" and I begin experiencing understeer. Not sure how I would describe my driving technique. How about give me a few options.....

Suspension components/bushings are all fairly new. At least new as in when the coilovers were installed four years ago August. Several rear components were swapped out during my extended stay at the shop last summer/fall/winter.

Alignment

Front
Camber -3.6L / -3.4R
Caster +7.2L / +7.3R
Toe -0.10L / -0.10R (toe OUT)

Rear
Camber -2.4L / -2.4R
Toe +0.20L / +0.20R (toe IN)

That is a lot of toe, especially in the rear. How did you decide on those values?

Here are a few things that come to mind on driving style, this isn't exhaustive and I'm not declaring any of these bad or good. There's plenty of guys who are fast that do aggressive stuff, and slow guys who use the "smoother" style. Some of these behaviors will contribute to faster tire wear.

Tire management is not easy so don't beat yourself up.


Aggressive driving style:
-you chuck the car into corners
-your inputs are aggressive
-the rear is sliding a lot
-you are often putting tires in the dirt to maximize your exit line

Smooth driving style:
-you use very long trailbraking
-it visually looks "slow"
-you are very conscious of understeer/oversteer and minimize it
-your inputs are deliberate

[SonnyJack]

Originally Posted by dparm

That is a lot of toe, especially in the rear. How did you decide on those values?

Here are a few things that come to mind on driving style, this isn't exhaustive and I'm not declaring any of these bad or good. There's plenty of guys who are fast that do aggressive stuff, and slow guys who use the "smoother" style. Some of these behaviors will contribute to faster tire wear.

Tire management is not easy so don't beat yourself up.


Aggressive driving style:
-you chuck the car into corners
-your inputs are aggressive
-the rear is sliding a lot
-you are often putting tires in the dirt to maximize your exit line

Smooth driving style:
-you use very long trailbraking
-it visually looks "slow"
-you are very conscious of understeer/oversteer and minimize it
-your inputs are deliberate

The shop that's handled my car (RRT) specializes in BMW's and I told them the car was dedicated to track only so I wanted a track only setup/alignment.

I would say my style is more on the smoother side which is very noticeable to me when I'm chasing down cars in front of me. I see lots of corrective steering inputs, back ends sliding back and forth and cars seemingly on the verge of disaster. That's not to say that these other cars are reckless but they do seem to be wringing out everything they can from their cars, which I am definitely not doing.

By comparison, I've always had horsepower to spare since I was supercharged before I began tracking the car. As a result, learning the lines and having smooth inputs has allowed me to hang with pretty much any car in my run groups w/o needing to be more aggressive. I hope that makes sense.

Picked up the new squared setup this afternoon so when I return to the track at the end of the month I'll begin the process of rotation and see how much that helps my wear.