16' performance tires on new A4

[larry leung]

General FYI on summer tires and why they don't work on ice and snow.

It's not JUST the tread pattern, which actually has a limited effect on glare ice (sipes help on less than perfect ice surfaces, and to a degree on glare ice, but that's another long topic) but the compound.

Good summer tires need to hold up to higher temps, and the rubber is designed to be the most grippy at higher temps. ALL tire compounds hit a temperature called the "glassing temperature" where the tire rubber acts, for all intents and purposes, like glass. For most summer tires, that temp is somewhere around 40 degrees F. Snow and ice occur at or somewhere near 32 degrees F, depending upon conditions, hence at that temp, summer tires are acting essentially like glass. Hence, the need for snow tires.

This is generally why race tires, slicks, and even DOT "R" compound tires pretty much suck when the temps drop to near 40 or even 50 degrees F. You can barely raise the tires above the glassing temps in an autocross, and it's very hard to get them to 
optimal operating temps. Road racers, by working up the tread temps slowly MAY get the tires up to a reasonable operating temp, but Autocrossers have no hope.

Note: All season tires of all types have compounds that are designed to operate over a very wide range of temps. Because of this, the compounds aren't generally as grippy as dedicated tire compounds. Add this to compromised tread patterns and those tires don't quite match the performance of dedicated tires, but they do get amazingly close, especially if you consider what they must do. 

Hope this helps with this question.

LL - NY



------Original Message------
From: "Michael S. Williams" <mike at borderlinemotorsports.com>
To: Jon Linkov <njconn at email.msn.com>, Edward E Griebel <edward_griebel at globalcrossing.com>, William Safford <73760.3533 at compuserve.com>, quattro at audifans.com
Sent: September 14, 2000 12:27:10 AM GMT
Subject: RE: 16' performance tires on new A4


BTW, i dont know why anyone caught this.  The stock tire for the A4 
sport package is the sport 8000E which is a dedicated, Z rated, 
summer tire.  it is great in the wet and dry, but ice and snow are 
big no-no's.  Go with your decision to get winter tires, that is the 
best solution.  They will last you a few years, give you much better 
safety than any all season tire would, and you dont have to wear down 
the 8000's in the winter....
-- 
Michael Sheridan Williams
Borderline Motorsports
Co-Owner/Publicist
http://www.borderlinemotorsports.com (coming soon)

United States Touring Car Championship 2000 Audi A4 2.8 quattro

San Francisco, CA
ICQ# 11740998

1983 UrQuattro, MC--1.8 BAR, borla, Coilover/Koni Yellows, Porsche 
Big Brakes, Tilton Dual Master Cylinders, Delrin Bushings f/r, 16x7.5 
OZ Mito's w/ Yoko A520's, Cibie H4/H1's, K&N
http://members.aol.com/daserde2
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