when to get new Hoosiers?

99t1

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Besides flat spots and visible damage when should you toss them? I know there are small holes to determine tread depth but what is the minimum depth? Also I hear the hardness and/or density can be measured?

I want to be able to measure if a used tire will be good for 30 minutes of road racing. Any guidlines?
 

Paul Fischer

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Go by heat cycles, a tire should maintain traction for the first 10-12 times it gets to optimum operating temperature. After that the heat cycling cooks the compound and they go hard. Heat cycle the tires by getting them to optimum temprature the first time out and then give them a full 24 hours to cure. That means ABSOLUTELY NO driving on them for a full 24 hours. The compound will be changed at the molecular level by the heat, the cure period helps fix the structural change. Your tires will wear longer with more grip if properly heat cycled.

There is no way to tell just by looking if a tire has been properly cycled or how many cycles it still has in it. Put a hash mark on your tires every heat to keep track, especially if you run multiple sets and store them for any length of time.
 

MichaelThurston

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The tool your looking for is called a durometer. It measures the hardness of the rubber. Two aspects of the tire you have to watch out for. The obvious one is running out of rubber; flat spots or just to many laps and you'll be on cords. The other is too many heat cycles or age. You will notice this in the first corner that you try to pull your normal number of G's. You won't be able too. Durometer should help you with this aspect, but I haven't proven this yet.
 
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99t1

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thanks Mike...check my thread with Hoosier. No one has any Durometer numbers.

From: "info" <[email protected]>
Date: Wed, 9 May 2001 08:42:09 -0500
To: "Morgan Reese" <[email protected]>
Subject: Re: when to toss Hoosiers?


Morgan,
Thank you for visiting www.hoosiertire.com <http://www.hoosiertire.com> and for taking time out to e-mail us your question(s). You are correct, the "small holes" on the tread surface are called depth gauges or wear gauges. These are used to determine how much tread is left on a race tire with a "slick" or smooth tread surface. Tires can be run until the gauges are no longer visible. Generally however, you may notice changes in the performance of the tire particularly if there are long periods of time between competitions. (were talking weeks/months). That is why teams prefer to run "sticker" tires many times as they tend to be quicker the first few circuits run. So, if you don't see any significant decrease in lap times or performance, But if your comfortable with the times your running, then you can look to the depth gauges to determine whether a lack of tread will help you determine whether to replace your used tire(s).
As far as tread hardness, we use a device that is commercially available called a "durometer". It basically measures resistance of the tread. This is a small hand held device that has a pencil type needle on one end that is placed on the tread surface. There is a dial meter on the face that then registers a reading with regard to how hard or soft the surface is. The harder the tread, the higher the reading, the softer the tread, the lower the reading.

Hope this has helped!
And thank you for your support of Hoosier.
Sincerely,
Hoosier Racing Tire Corp.

From: Morgan Reese <mailto:[email protected]>
To: info <mailto:[email protected]>
Sent: Wednesday, May 09, 2001 11:57 AM
Subject: Re: when to toss Hoosiers?

thanks for the info...I purchased a durometer from longacre. What numbers would be considered "still sticky" and what numbers would be "hard"?

From: info <[email protected]>
To: Morgan Reese <[email protected]>
Date: Wednesday, May 9, 2001 4:05 PM
Subject: Re: when to toss Hoosiers?

Morgan,
The answer to your question isn't that simple. The durometer reading is a relative one that has many variables that affect the ultimate reading. The best thing you can do is, record the conditions (track/ambient) and the laps on the tires that you are measuring along with lap times. There will probably be a correlation between the durometer reading and the lap times over time. But it isn't something that we can predict for you. Sorry we weren't more help, but this is where you will become an "expert" on your own tires.
Sincerely,
Hoosier Racing Tire Crop.
 
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