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Old 08-28-2017, 10:52 PM   #1
chopsticksonly
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Default Tires splitting at the edge... how to avoid in the future?



I was told this happened as I was going in a corner too hot, any tips to avoid these situations in the future?
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Old 08-29-2017, 12:11 AM   #2
n2oiroc
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not enough negative camber and going in too hot caused that. also, what was your cold tire pressure? some tires handle track abuse better than others so look into that when you replace them.
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Old 08-29-2017, 12:48 AM   #3
Patrick Olsen
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Uhhh, your tires aren't "splitting at the edges", they're fricking bald. The way to prevent that is to buy new tires and not run them until they're fricking bald.
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Old 08-29-2017, 01:28 AM   #4
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Quote:
Originally Posted by n2oiroc View Post
not enough negative camber and going in too hot caused that. also, what was your cold tire pressure? some tires handle track abuse better than others so look into that when you replace them.
cold pressure is the oem recommended. i think it was 33 front/32 rear?
it's weird because only the driver left side is that bald

Quote:
Originally Posted by Patrick Olsen View Post
Uhhh, your tires aren't "splitting at the edges", they're fricking bald. The way to prevent that is to buy new tires and not run them until they're fricking bald.
for some reason, only the driver side outer edge is this bald.
all 4 tires have about 3-4 mm tread left
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Old 08-29-2017, 01:44 AM   #5
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/\thats not a lot. How many miles on these tires?

After you get your new tires go get an alignment. I get one every year whether I need it or not.
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Old 08-29-2017, 09:01 AM   #6
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Quote:
Originally Posted by carlos.danger View Post
/\thats not a lot. How many miles on these tires?

After you get your new tires go get an alignment. I get one every year whether I need it or not.
Car has 34k kms, those tires probably around 24k km (due to winter driving too). Alignment was completed one month ago
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Old 08-29-2017, 09:05 AM   #7
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Time for new tires. (Obviousely)
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Old 08-29-2017, 12:42 PM   #8
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Quote:
Originally Posted by chopsticksonly View Post
for some reason, only the driver side outer edge is this bald.
all 4 tires have about 3-4 mm tread left
Did you ever rotate the tires? Wear like that doesn't happen overnight. How has the car been used? Strictly street driving, auto-cross, track days?

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Originally Posted by chopsticksonly View Post
Alignment was completed one month ago
And what were the numbers (before and after)? What did the alignment shop say about the grossly uneven tire wear a month ago?
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Old 08-29-2017, 01:13 PM   #9
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So, I take it you've been autocrossing on asphalt. It looks like you've experienced some understeer...

You need a lot more negative camber at the front wheels (-2.5 degrees or more - you will need to add aftermarket camber bolts), you also need to control your entry speeds before turning into a corner. Also when you're in a corner and experiencing understeer, you should be off the throttle trying to scrub speed, and/or reducing steering input until your front tires stop screaming for mercy.

Try this on your next set of tires.
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Old 08-29-2017, 08:41 PM   #10
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Quote:
Originally Posted by Patrick Olsen View Post
Did you ever rotate the tires? Wear like that doesn't happen overnight. How has the car been used? Strictly street driving, auto-cross, track days?


And what were the numbers (before and after)? What did the alignment shop say about the grossly uneven tire wear a month ago?
Yes I have rotated tires after every season tire change (summer -> winter). The car is mostly used for daily street driving, but went on auto-cross a few times and a couple mild track days. I have never realized never realized how bald the side was until it splitted at the track.

Subaru did the alignment after they replaced my strut mounts. They did not make any comments about the tire.


Quote:
Originally Posted by T-37 View Post
So, I take it you've been autocrossing on asphalt. It looks like you've experienced some understeer...

You need a lot more negative camber at the front wheels (-2.5 degrees or more - you will need to add aftermarket camber bolts), you also need to control your entry speeds before turning into a corner. Also when you're in a corner and experiencing understeer, you should be off the throttle trying to scrub speed, and/or reducing steering input until your front tires stop screaming for mercy.

Try this on your next set of tires.
As I mostly street drive the car, will the -2.5 degrees cause more unnecessary wear while daily driving? I did understeer and the tires were squealing big time. I will try your tips on my new set of tires.
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Old 08-30-2017, 10:16 PM   #11
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Auto-cross will chew up tires when you alignment is not dialed properly to the necessary specs. But with that being said -2.5 degrees of negative of camber might have a slight decrease in life of tire if you are looking to get 20k+ miles per set of tires.

Here are my tires after about 70 autocross runs and with negative -3.2 front camber for this year. I rotate after every event weekend too.



Left side of this image is the outside of the tire.



McPherson front suspension are just going to wear the tires like this as the outside tire pushes more positive within a corner and tries like hell to put grip and power down to keep the car moving in the proper direction... but it just can't and it wears the outside edge. Go look around around at any of the AWD auto-class cars and you will see very similar wear on them.

For a person that enjoys spirited driving and the occasional auto-cross I would go for around -1.6 camber or whatever the factory Subaru front bolts will allow for and this should help plenty with less wear and better cornering. If you find yourself interested in a more dedicated setup then you can further your alignment angles and look at suspension upgrades and better tires. Good luck.
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Old 08-31-2017, 12:23 PM   #12
Patrick Olsen
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Quote:
Originally Posted by chopsticksonly View Post
Yes I have rotated tires after every season tire change (summer -> winter). The car is mostly used for daily street driving, but went on auto-cross a few times and a couple mild track days. I have never realized never realized how bald the side was until it splitted at the track.
These sorts of details would've been useful in the original post; auto-x and track use are the main drivers of that sort of tire wear.

Quote:
Originally Posted by chopsticksonly View Post
Subaru did the alignment after they replaced my strut mounts. They did not make any comments about the tire.
http://i.imgur.com/m9qG9MY.jpg
Typical, low-effort alignment - adjusted toe and didn't touch anything else. As others have said, you want more negative camber up front; just ask for the alignment shop to give you the max negative camber that they can get.

Quote:
Originally Posted by chopsticksonly View Post
I did understeer and the tires were squealing big time.
OK, so for future reference, "squealing big time" is bad. Regardless of what alignment you get on the car, if you over-drive your equipment, you will prematurely wear things out and you will actually go slower. Learn to drive within the limits of your equipment. T-37's comments are a good start.
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