Date: Thu, 02 Sep 1999 08:32:56 -0700
From: "Jim S. Powell" <jsp98m3_at_home.com>
To: "bmwuucdigest_at_List-Server.net" <bmwuucdigest_at_List-Server.net>,
Subject: [E36M3] Heat Cycling
I've heard lots of home brew heat cycling stories in the past, some not
agreeing with each other. Suggestions of 100 miles, 20 miles, skid pad
etc. I got curious the other day and sent off a question to BFG about
how to do this at home for auto-x and driving school usage. Here's
their response. I know this is pretty basic stuff to most people but I
thought it might help many people and maybe end up on a FAQ somewhere.
>>> BFG rep from here on out:
With this activity, the inflation pressure provided earlier should be
okay. As for heat cycling, you need to get the tire to a minimum of
165 degrees Fahrenheit. Driving around the block, or in a circle at
the local shopping mall can generate the heat you need. Since these
tires are hysteresic, meaning they will generate additional heat with
use, the quick way to generate heat is to input 5 degrees steering
input and drive modestly in a circle. Reverse direction and drive in
the same manner. (A large parking area is suitable for this exercise
as long as you don't start "Hot-dogging" the car and catch the notice
of the security folks.) It is not a case of how long you do it, it is
a case more of how you do it. After you exercise the tire, get out of
the car and put your hand on the tread. If you can't, because of the
temperature, you have probably given it a pretty good heat cycle.
Let the tires set for a minimum of 24 hours and preferably 48 before
using them in competition.
In my previous message on cycling I left the tire pressure info out on
purpose as it can and will vary by tire. BFG recommendations for older
R1s (not the G-Force) are 1 lb pressure per 100 lbs of car weight. Then
put 2 more pounds in the end of the car with the motor. On an E36 that
would be 32 pounds all around and then bump the front (motor end) to
34. Experiment from there.
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