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Re: GGF & Tires

To: Eljssp8@aol.com, Toy4speed@aol.com
Subject: Re: GGF & Tires
From: "Donald R McKenna" <donbarbmckenna@earthlink.net>
Date: Thu, 17 Aug 2000 11:08:35 -0700
To all,

Our experience, on the GS, with Kumhos is the following:

1. First couple of events (heat cycles) on un-heat-cycled and un-shaved
Kumhos, the tires are really squirmy and slow on a clean dry surface.

2. After only one srubbing/heat cycle, on the next outing, if its wet, they
are really very good rain tires until the puddles get too deep. In a
downpour, street tires will probably be faster.

3. As long as there's reasonable tread (first third of life), they continue
to be far supperior to Hoosiers in the wet.

4. The previous comments about wet also apply to surfaces like the "new"
Oakland lot, wet or dry.

5. On dry and clean surfaces, they are at their best while in the second
third of tread wear. As they get into the last third of tread wear, grip
begins to "fall-off", gradually, until you cord them.

6. The "hot-dogs" get to #5 by shaving and heat-cycling before running the
first time. This is when, after only a run or two, the Kumhos are at their
best.

7. Finally, the Kumhos seem to last longer than, for instance, Hoosiers.
They start with more tread .162" vs .132" on Hoosiers in our size tires. Our
experience is the Kumhos will go 70-80 minutes of run time (84-96 50 second
runs), or more compared with 50+ minutes on Hoosiers. The other side of the
equation is that the Hoosiers seem to be faster from beginning to end but,
only on DRY, CLEAN SURFACES.


Now to Eric's situation. Although I've not run at GGF this year, it sounds
like there's a little of the "oakland" situation to contend with. In that
kind of course situation, the first group can be the "fastest" of the day,
relatively speaking, because they don't have to contend with the gravel
stirred-up by previous groups. As the day progresses the "CLEAN" line
probably gets quicker but narrower as more and more loose stuff collects on
the edges of the clean path. Once there is a clean path, narrow cars driven
with precision on the clean line can really be fast but, wider cars will
have more difficulty staying out of the loose stuff. Also, the "clean" path
is seldom the fastest line, if gravel wasn't a problem so, the trick is to
try and figure out how to find and stay on the clean line. In general, the
safest way to find the line, if you can't see it, is to stay in tight on
corners, as the wider you get the more loose stuff you'll, generally,
encounter and the clock really ticks fast when you're in that stuff.

        Don
----------
>From: Eljssp8@aol.com
>To: Toy4speed@aol.com
>Cc: Smokerbros@aol.com, ba-autox@autox.team.net
>Subject: Re: GGF & Tires
>Date: Thu, Aug 17, 2000, 8:45 AM
>

>Congrats to Charlie, I continue to envy drivers who are faster than I.
>Don brings up a good question; how long does Kuhmos last? As a new Kuhmos 
>user, I am curious as to it's true useful life. Starting with the first GGF 
>event, thru the latest GGF event, I have made 39 runs of  44 to 55 sec each. 
>My first GGF event, the tires felt great, while last Sunday's GGF event, I 
>spun during my last two runs, (3rd run group), I was overly aggressive, 
>granted, driver error had alot to do with it. The question is, even though 
>the Kuhmos still show traces of tread pattern, could it be that it does'nt 
>grip as well as full tread?
>TIA, 
>Eric Cheung
>A Stock/PAX
>

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