Forward: More R1 tire info.

[John Karasaki <johkar@teleport.com>]

>X-From_: racing-admin@porschelist.org  Thu Aug 27 09:30:59 1998
>From: KGBELDEN@aol.com
>Date: Thu, 27 Aug 1998 11:57:30 EDT
>To: "Racing" <racing@porschelist.org>
>Subject: Re: R1's
>X-Message-Id: <85c466d0.35e581ea@aol.com>>
>Reply-To: KGBelden@aol.com
>Sender: racing-admin@porschelist.org
>X-Lyris-To: [johkar@teleport.com]
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>
>In a message dated 08/26/1998 4:33:10 PM EST, gvisgilio@worldnet.att.net
>writes:
>
><< Just put on a new set of R1's and noticed that the inside
> part of the tire is worn much more than the outside part.
> This is (I guess) expected in that I run negative cambers of
> -3 front and -2 rear. However, the "tread" on a properly
> mounted R1 is on the outer (less wear) edge. Since most cars
> run at least as much neg camber  if not more, does this make
> sense? BFG must know what they're doing, but to a layman it
> looks like the tread is on the wrong side. Perhaps my tires
> are not rolling over under side load as much as BFG expects,
> but I don't use higher than they recommend for pressures and
> usually less. Car is  a 924S with konis/roll bars F&R/corner
> wgt balanced/etc. >>
>
>First, the BFG R1's were designed to run with less negative camber than other
>track tires.   The inner and outer sidewalls are of different stiffness, to
>compensate for the reduced negative camber adjustment generally available on
>"street" cars, and to provide an advantage to competitors in certain classes
>of racing which require stock alignment settings.  Three degrees is too much
>camber for an R1; two degrees is pushing the limit.
>
>Second, if the wear on the inside tread is more pronounced on the front than
>at the rear, I'd suspect too much toe out at the front.  Even a little toe
out
>will quickly wear out the inside tread, especially on the tire that's on the
>inside of most turns.  For example, at a track like Lime Rock with only one,
>slow left-hander, too much toe out will ruin the right front tire, but
wearing
>out or blistering the inside tread, far in advance of the other tires.  The
>outside front tire will also show accelerated wear on the inside tread.  
>
>Third, if you brake hard and have soft front springs, especially on a car
>that's been lowered, you'll get lots of additional negative camber when the
>front suspension compresses under braking, which will also prematurely wear
>the inside tread on the front tires.  
>
>Finally, running lower than recommended pressures will cause premature
wear on
>these tires, especially between the second and third tread blocks (as I
>recall) in a manner you may have heard referred to as the "Evil Groove of
>Doom" (EGOD).
>
>Hope this helps.
>
>Kevin Belden
>
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Best Regards,

John Karasaki
Portland, OR