Severe Inner Tire Wear

[Jeff.Bernstein at pneumaticscale.com]

Bernie,

My first sentence can be substantiated by any knowledgeable alignment person
who has aligned a lot more cars than I'm sure you have.  My years of
experience with many different types of cars has also proven that it is the
toe-in that has the most influence on inner tire wear.  I have run negative
camber on every car that I have owned without wearing the inside of my
tires. 

All these years I wondered why you thought your Bernie Benz strut brace
would help with tire wear and now I understand.  You actually think that
negative camber is used to correct strut alignment.  You can't possible say
you know what suspension stability is when you obviously don't even
understand what it is and what is important about it.    

On race cars where all the suspension points are reinforced, you still run
negative camber.  This is because the most flexible component in the
suspension is the tire.  It is the tire deflecting that is the reason for
negative camber.  In fact some high performance tire manufactures will even
recommend additional negative camber depending on their tire design.

I can assure you that if "T" puts on your Bernie Benz strut brace his tire
wear problems will not go away.  I am positive that if he gets his toe-in
problem corrected his tires will wear for many miles.  I am also sure that
any knowledgeable alignment mechanic will agree with me.

Jeff

 
-----Original Message-----
From: Bernie Benz [mailto:b.benz at charter.net]
Sent: Friday, July 16, 2004 4:37 PM
To: Jeff.Bernstein at pneumaticscale.com
Cc: 200q20V mailing list
Subject: Re: Severe Inner Tire Wear


Jeff, 

We disagree in principle on the reasons for negative camber.  Negative
camber is used to correct for the strut tower deflection caused by lateral
turning forces.  In the correct amount, the - camber just offsets the +
camber effect of the strut tower deflection resulting in net zero camber,
i.e. maximum tire contact patch on the outside tire.

Thus, the better idea would be to minimize the strut tower deflection such
that less - camber is needed to correct for the maximum turn strut tower
deflection.  This condition that will be more nearly correct for lesser
turns and straight ahead driving.  My strut brace accomplishes this to a
maximum, short of chassis redesign.

Further, I strongly disagree with your first sentence.  BTDT with DIY
alignment where I know with certainty exactly what the alignment settings
and what the suspension stability is.

Bernie

> From: Jeff.Bernstein at pneumaticscale.com
> Date: Fri, 16 Jul 2004 13:42:22 -0400
> To: 200q20v at audifans.com
> Subject: Severe Inner Tire Wear
> 
> Too much negative camber will add very little extra wear to the inside of
> tires.  I run between 1 to 1.75 on all my Audi's and nearly 2 degrees of
> negative camber on my Porsche without any problems with excessive inside
> tire wear.  I set my cars up this way so that they handle better in the
> corners.  Setting the car to 0 degrees camber will make your car corner
> poorly.  Audi's have enough under-steer by design, you don't want to add
any
> more by setting the camber to 0 degrees.
> 
> If your toe-in is incorrect you will definitely have increased tire wear
> which could be made worse by the extra negative camber.  Incorrect toe-in
is
> the major reason for increased wear on the inside of the front tires.  I
> would be willing to bet that your toe-in is way out of specification.  If
> you fix the toe-in you can ignore the excessive negative camber and just
> enjoy the increased cornering ability that comes with the extra negative
> camber.
> 
> Jeff 
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