I got into autocross this year - and next year hope to try some of the driver's ed track events....

So what is the difference between all the different tires?

I hear Khumo, Toyo, Hoosier - and see them all out on the auto cross and at our recent section event at VIR. But which one works - and does not cost a fortune?

I am running a '97 C-280 - picked up some recent c class 16" rims - which I spent the end of the summer chewing up the Continential that were on them.

This past weekend we had our last AX and someone said - imagine how well you would do with race tires on there.

So my question is which one's? I understand that the Khumo's are the least expensive - and I see alot of them out there. I know the Toyos are $150+ - are there others that I should look at?

Any and all input would be great!!!

__________________
W Hopper
GWS-MBCA President
Check out MBCA's Largest Event in 2010 - StarFest® 2010
www.starfest2010.org
http://twitter.com/starfest2010

get Kumho Victo-Racer V700's ......

tire search

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So what is that all about? What does Heat Cycled mean - I assume shaved means that they have been cut down.

WWH

__________________
W Hopper
GWS-MBCA President
Check out MBCA's Largest Event in 2010 - StarFest® 2010
www.starfest2010.org
http://twitter.com/starfest2010

Heat Cycling
As participation in autocrossing, track days, driving schools and road racing continues to grow in popularity, the tire manufacturers have developed unique DOT legal competition tires which feature very sophisticated tread compounds. However just like other high performance parts, these tires will provide more consistent performance and last longer if they are properly broken-in.

The first time a competition tire is used is the most important. During that run, its tread compound is stretched, some of the weaker bonds between the rubber molecules will be broken (which generates some of the heat). If the tires are initially run too hard or too long, some of the stronger bonds will also be broken which will reduces the tire's grip and wear qualities. Running new tires through an easy heat cycle first, and allowing them to relax allows the rubber bonds to relink in a more uniform manner than they were originally manufactured. It actually makes them more consistent in strength and more resistant to loosing their strength the next time they are used. An important heat cycling step is that after being brought up to temperature, the tires require a minimum of 24 to 48 hours to relax and reform the bonds between their rubber molecules.

Looking at the heat cycling system, it positions a mounted and inflated tire between rollers which apply pressure while the tire is rolled up to speed. It is very important to note that this allows heat to be generated as a result of deflecting (stretching) the tire within its normal operating range. There is no "artificial" heat added (no oven, no forced air, etc). Then they receive the stamp showing they are Tire Rack heat cycled.

Measuring the tread temperatures with a tire pyrometer we confirmed that in our controlled environment we were able to achieve appropriate and more consistent temperatures across the tire's tread without causing treadwear. All of these are significant improvements over heat cycling tires on our test track. And the 24 to 48 hour waiting period efficiently occurs while the tires are in transit to you. That means the tires are ready to use when they arrive!



Shaving:
One of the reasons radial racing slicks are so effective is because they feature shallow tread depths and their contact patch acts as a single unit. However, any tread design breaks up the contact patch into smaller elements and additional deep tread depth (required to enhance wet traction) allows tread block squirm which will reduce dry performance. This means that tires typically provide their worst wet traction ... and their best dry performance just before they wear out. However, its also important to remember that the heat generated every time a tire is driven activates bonding agents in the rubber. As this process is repeated continually throughout the tire's life, its rubber compounds gradually harden and loose flexibility reducing the tire's grip. Therefore, a shaved "new" tire will provide more traction than a tire worn to the exact same tread depth after being driven for thousands of miles on the road.

Tire shaving is an effective means of permitting more of a tire's performance capability to be realized early in its life. Tire shaving removes tread rubber and reduces tire weight by several pounds. A shaved tire's tread profile will usually result in a slight increase in the width of the tire's contact patch putting a little more rubber on the road. The resulting shallower tread depths reduce the tire's slip angle, increases its responsiveness and help stabilize its cornering power by minimizing tread block squirm. Minimizing tread block squirm also reduces heat buildup and the risk of making the tire go "off" by overheating its tread compound. And in many cases, shaved tires used in competition actually have a longer useful life than tires that begin being run at full tread depth.

So with all of these benefits, the next important question is: "How far should a tire be shaved?"

Hoosier R3S03, A3S03, R3S04 and A3S04 radials are manufactured with 4/32 to 4.5/32” of molded tread depth and do not require tire shaving.

Most other DOT-legal Competition tires begin with about 6/32" of molded tread depth. While some tires do not require shaving for dry autocross use, all of them will benefit from shaving to about 4/32” tread depths for driver’s schools, track days and competitive track use in dry conditions.

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Shaving I can understand - hate to do it - on me or my tires.

Do I have to buy wheels and tires to get them heat cycled - or can I buy the tires and have them heat cycled and then installed later on my rims - or do I have to send you the rims to have the tires mounted on them before they are heat cycled?

Or is all this just another marketing ploy?

__________________
W Hopper
GWS-MBCA President
Check out MBCA's Largest Event in 2010 - StarFest® 2010
www.starfest2010.org
http://twitter.com/starfest2010

you do not have to buy wheels in order to have the tires heat cycled or shaved

__________________

Please, call me to place orders or for more info
use my name for on-line orders