Odd tyre wear - track tyres

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Pete K
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Odd tyre wear - track tyres

Post by Pete K »

I discovered that my front tyres have been waering a little strangely. There is an obvious "valley" just off centre. Both fronts have it and it is in the direction of the outside of the car on each side.

I'm guessing this means that my pressures are too high, but that's just guessing! The 520i runs about 3.5 degrees of neg camber so the groove is fairly close to the edge of the contact patch (in a straight line).

Anyone have any ideas about this? They lasted 2 years and have gone a bit hard, so I haven't lost out on life. Just intrigued. Maybe some changes would make them perform better if they wore evenly?

There's a photo at http://team-orange.blogspot.com/2010/01 ... ss-of.html

Cheers
Pete K
'75 520i (track day special)
'81 M535i (dream car)
'79 323i (wife's little cruiser)
'02 320ci/330ci track car (b30 swapped 320ci)
'97 Ford Laser (1st ever new car)
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Peter Florance
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Post by Peter Florance »

Hi Pete
I'd guess too much air and not enough negative camber
Peter Florance
First Fives.Org - The E12 Registry
1981 E-Street Prepared Euro BMW 528i w/3.5L & Megasquirt Fuel Injection
http://www.firstfives.org
mailto:peter@firstfives.org
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Pete K
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Post by Pete K »

Thanks Pete. I'll try less air. I've got as much camber on as she'll do, so I guess I'll just have to live with it.

If I ever get around to upping the spring rates, the reduced roll might help too.

Cheers
Pete K
'75 520i (track day special)
'81 M535i (dream car)
'79 323i (wife's little cruiser)
'02 320ci/330ci track car (b30 swapped 320ci)
'97 Ford Laser (1st ever new car)
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Peter Florance
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Post by Peter Florance »

Pete K wrote:Thanks Pete. I'll try less air. I've got as much camber on as she'll do, so I guess I'll just have to live with it.

If I ever get around to upping the spring rates, the reduced roll might help too.

Cheers
How much toe are you running?
How much camber?

Yes, if you're getting excess roll, that could be an issue as well
How about a picture of hard corning?
Peter Florance
First Fives.Org - The E12 Registry
1981 E-Street Prepared Euro BMW 528i w/3.5L & Megasquirt Fuel Injection
http://www.firstfives.org
mailto:peter@firstfives.org
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Pete K
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Post by Pete K »

I'm running zero toe at the moment and 3.2 degrees of neg camber.

I'm not good at adding pictures, but this should be one.

Image

Cheers
Pete K
'75 520i (track day special)
'81 M535i (dream car)
'79 323i (wife's little cruiser)
'02 320ci/330ci track car (b30 swapped 320ci)
'97 Ford Laser (1st ever new car)
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Peter Florance
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Joined: Tue Jul 25, 2006 8:32 pm
Location: Virginia Beach VA
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Post by Peter Florance »

Body roll doesn't seem excessive. Corner weights pretty close?
Peter Florance
First Fives.Org - The E12 Registry
1981 E-Street Prepared Euro BMW 528i w/3.5L & Megasquirt Fuel Injection
http://www.firstfives.org
mailto:peter@firstfives.org
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Chris Itterly
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Post by Chris Itterly »

Sorry to interject unrelated babble, but I have always loved that 520i, you've doe a great job, color, power bulge hood, chrome side mirrors, the stance, and those wheels are sweet. It looks great cornering!!

We always run clockwise, at least every track I've been to, I can only figure it's for driver safety, side impact from a following car, but who knows. Anyway, I thought a left hand drive car might actually produce an advantage by having the car loaded to that side. The clockwise direction basically produces a 2:1 ratio of right to left turns..... every little bit helps...

Sorry just had to get that out.

I also get a similar wear pattern in the fronts with my e21, but I can only get 1.9 degrees of neg camber, even with plates.....
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Pete K
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Post by Pete K »

Thanks Chris. It's nice to be appreciated :) Most people have a bit of a laugh when we wheel it off the trailer. That normally only lasts until they find their $80,000 M3 is slower than a $2,000 4 cylinder!

Cheers
Pete K
'75 520i (track day special)
'81 M535i (dream car)
'79 323i (wife's little cruiser)
'02 320ci/330ci track car (b30 swapped 320ci)
'97 Ford Laser (1st ever new car)
User avatar
Peter Florance
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Posts: 539
Joined: Tue Jul 25, 2006 8:32 pm
Location: Virginia Beach VA
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Post by Peter Florance »

I know it's unlikely, but if you find yourself in east coast of USA during your stay, love to have you co-drive the beast at an autocross

(actually either of you, Pete or Chris)

:)
Peter Florance
First Fives.Org - The E12 Registry
1981 E-Street Prepared Euro BMW 528i w/3.5L & Megasquirt Fuel Injection
http://www.firstfives.org
mailto:peter@firstfives.org
User avatar
Pete K
Posts: 206
Joined: Thu Jan 08, 2009 12:04 pm
Location: Perth
Contact:

Post by Pete K »

That's sounds great Pete! Our other office is in Bethlehem PA and I'm sure I'll be there at some point. Not exactly just down the road, but a lot closer than Utah!

Cheers
Pete K
'75 520i (track day special)
'81 M535i (dream car)
'79 323i (wife's little cruiser)
'02 320ci/330ci track car (b30 swapped 320ci)
'97 Ford Laser (1st ever new car)
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