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Re: 25PSI

To: Max Heim <mvheim@studiolimage.com>
Subject: Re: 25PSI
From: James Nazarian Jr <James.Nazarian@Colorado.EDU>
Date: Mon, 21 Aug 2000 15:53:39 -0600 (MDT)
In my experience autocrossing the opposite is true.  Before we get going
let me spec my car for you.  Stock springs all the way around.  The front
sits two inches low for some unkown reason.  Ride height is 11.75/13.5
stock sway bar up front with polyurethane mounts, effectively upping the
bar thickness one increment.  V8 Bushings in front and stock rims with
Cooper Response RST 185/70R14 tires.  I find that equal tire preassures
cause too much understeer.  On the road I run at 28f/32r on the track I
have run as high as 35f/40r.  I find, in my setup, that a differential of
4-6psi will allow the right balance in the handling.  Of course actual
preassures vary per day and the conditions.  So far I have found no
evidence of tire wear due to these preassures, but it does make the ride a
bit tougher on the road.  This is not to say that my car doesn't
understeer, it will if driven into a corner too fast, but it will
generally have slight understeer on corner entry transitioning to slight
oversteer through the apex.  I can't take credit for doing that on
purpose, but I like the handling that way.

James Nazarian
'71 B roadster
'71 BGT ever so slowly turning into a V8
'63 Buick 215 

"I sure wish I had a racer's budget, or are the racers just better at
explaining expenses to the wife?"
-Unknown

On Mon, 21 Aug 2000, Max Heim wrote:

> Hmmmm....
> 
> 1) I believe that recommended tire inflation for B roadsters, at least, 
> is 3lbs. greater at the back than the front...
> 
> 2) ...and the reason for this is to AVOID oversteer; therefore, if I 
> understand this correctly, your setting of 30f/35r would actually induce 
> mild understeer. Conversely, the 25/25 setup should induce mild oversteer 
> -- and in my experience, actually does.
> 
> All this assuming stock spring rates and stock front sway bar, no rear 
> sway bar...
> 
> Comments?
> 
> 
> 
> ATWEDITOR@aol.com had this to say:
> 
> >
> >In a message dated 8/18/00 5:50:49 PM, ccbrown@cwcom.net writes:
> >
> ><< and I ride on 25psi all round >>
> >
> >Heck, I ride on 30psi, and it sticks to the corners great.  Boost the rears 
> >to 35psi and you can get into oversteer with power a bit easier.  Of course, 
> >this may shorten the life of your tires somewhat.
> >
> >Jay Donoghue
> >72B
> >72B-GT
> >66 Mustang
> >
> 
> 
> --
> 
> Max Heim
> '66 MGB GHN3L76149
> If you're near Mountain View, CA,
> it's the red one with the silver bootlid.
> 


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