What's a Heat Cycle
01-20-2008, 07:59 PM
#1
Racer
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Member Since: Jun 2004
Location: Reinholds PA
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What's a Heat Cycle
Does a heat cycle mean a tire has been brought up to a specific temperature? What is that temp?
How many heat cycles does an A6 or V710 have it them before they lose their grip?
The reason why I ask is that the LS or HS autoxs and HDPE events I do don't get the tire temp above 125 to 130F range, so are these outting considered heat cycles?
How many heat cycles does an A6 or V710 have it them before they lose their grip?
The reason why I ask is that the LS or HS autoxs and HDPE events I do don't get the tire temp above 125 to 130F range, so are these outting considered heat cycles?
01-20-2008, 09:17 PM
#2
Team Owner
This is from the Tire Rack site
Hope it helps
Tire Break-In Procedure
Proper break-in will not affect initial performance but will increase the competitive life of the tire.
The procedure can be broken down into phases.
1st phase: The initial run heat cycle
2nd phase: The length of the time the tire is allowed to "cure"
The Initial Run Heat Cycle
R6 Roadrace: The first laps for the tire are critical for setting up the durability and competitive life. The first session should consist of no more than 10-15 minutes of running. The early part of the session should be run at an easy pace, with the speed gradually increased until the end of the session. The final lap should be run at the fastest possible speed. The intent is to achieve maximum tire temperature on the last lap. At this point the car should be brought in and the tires allowed to cool at a normal rate.
During the initial run-in process, the inflation pressure should be 3-5 psi higher than you would normally use. The best progression would have the driver taking 4-7 laps to accomplish this break-in. Each lap should be approximately 7-10 seconds per lap faster than the previous lap. The goal is to have the tire temperature as high as possible on the last lap without "shocking" the tire during the warm-up laps. In essence, no wheelspin, late braking, or sliding. The last lap should be at, or very close, to the maximum possible.
After completing the initial heat cycle detailed above, the length of time the tire is allowed to rest out of service is possibly most important. The barest minimum for this process to be beneficial is 24 hours (not "the next day"). Any less than this is a waste of time. The best situation would allow a week before using the tire again. The tires should be removed from the vehicle while they cure, or the vehicle lifted to remove its weight from resting on the tires.
Proper tire management is a difficult process. The payoff is greatly increased competitive tire life.
A6 Autocross: For autocrossing, the A6 does not need the same break-in procedure as the R6. The A6 needs a minimal scuff-in session before the first autocross run. This "session" can comprise of simply driving around the event site at minimal speeds on the A6 set of tires. By scrubbing off the newness of the tread (only minimal or no shine remaining) prior to your first competitive run, the A6 tires will be more consistent in handling, grip and responsiveness on the first run. If this is not completed, running on un-scuffed A6 tires on your first run may result in the tires not gripping properly, or feeling like they "skate" over the course surface. It is acceptable to run 3 - 5 psi higher when scuffing in a new set of A6 tires, but be sure to reset them to the correct operating pressures before your first autocross run. As you compile autocross runs on your new A6 tires, they should become more consistent in run times.
Tire Pressure Recommendations for Competition
Traditionally, Hoosier tires have often required higher pressures than other brands. This has changed with the A6/R6.
Roadrace/Track Applications
Vehicle
Size Recommended
Hot Pressure Cold
Pressure
1800-2200 lbs 34-37+ 26-31
2200-2600 lbs 35-38+ 27-32
2600-3000 lbs 37-41+ 27-32
over 3000 lbs 38-43+ 27-33
+ Higher pressures will improve the performance capability but will require a more sensitive feel to take advantage of the increase.
One characteristic of the tires is the tendency to "skate" initially (when inflation pressures are correct). It is important to resist lowering the pressure to attempt to eliminate this feeling. Dropping the pressure too far may improve the "feel" of the tire however it will also lower the performance and increase the wear rate.
Autocross Applications
For autocross applications, your starting pressure for the first run should be within 1-2 psi of the recommended hot pressures shown above. After the first run and each subsequent run, keep resetting the pressures back to your target hot pressures before taking the next run. This way your tires are at the proper pressure during the bulk of every run you take.
Tire Temperature Recommendations
For best performance the expected temperature range will vary from track to track. Generally, optimum traction will be generated when the pit lane temps show 180-200 degrees for the R6 in Roadrace applications, and 140-150 degrees for the A6 in an Autocross application.
Chassis Setup Recommendations
For optimum performance the tires will require around 3 degrees of negative camber. There will be a trade-off in maximum performance to maximize wear. Generally 1/2 degree less than optimum will result in the best compromise for wear and speed. Less than 2.5 degrees can result in excessive wear on the shoulder junction.
The tires should offer better performance with spring/shock rates that are higher than previous brands you may have run.
Things to Consider
These tires are molded to their designed tread depth. They do not require shaving to be prepared for competition use. Shaving the tire further will not improve performance. It is not recommended that they be altered in this manner.
Due to extremely light construction, the Hoosier tires have a much lower polar moment than many other radial tires. This translates to a very low rotational mass, which is a good thing for performance applications. The down side to this feature is that the tires don't resist "spikes" in braking force as well as a heavier tire might. As a result, there is a tendency for drivers to "flatspot" a tire the first time really getting to the limit. Vehicles equipped with ABS will benefit from its use. If you do not use ABS, it is recommended that you make an effort to minimize stabbing the brakes until you have some experience with the feel of the tire under hard braking.
The light construction also provides less protection from impact damage and punctures. Off-course excursions or running over debris on the track will likely result in tire damage.
These tires are not directional or asymmetrical. Once some wear has occurred it may be desirable to flip the tire on the wheel so a "fresh" shoulder now faces outward in order to even out the wear and maximize tire life.
Following the recommended break-in procedure will require a lot of planning to make it work. The benefits to doing it right include greatly increased tire life as well as more consistent performance and durability under stress.
The Hoosier D.O.T. Radial tires are extremely good in dry conditions, however they don't make very good wet weather tires. Having dedicated rain tires available will be necessary for your team to be properly prepared. Hoosier makes a D.O.T.-approved wet tire called the D.O.T. Radial Wet that has been proven to be superior at full tread depth in steady "wet" conditions. This tire can also be shaved to partial tread depth for use as an intermediate wet tire.
Hope it helps
Tire Break-In Procedure
Proper break-in will not affect initial performance but will increase the competitive life of the tire.
The procedure can be broken down into phases.
1st phase: The initial run heat cycle
2nd phase: The length of the time the tire is allowed to "cure"
The Initial Run Heat Cycle
R6 Roadrace: The first laps for the tire are critical for setting up the durability and competitive life. The first session should consist of no more than 10-15 minutes of running. The early part of the session should be run at an easy pace, with the speed gradually increased until the end of the session. The final lap should be run at the fastest possible speed. The intent is to achieve maximum tire temperature on the last lap. At this point the car should be brought in and the tires allowed to cool at a normal rate.
During the initial run-in process, the inflation pressure should be 3-5 psi higher than you would normally use. The best progression would have the driver taking 4-7 laps to accomplish this break-in. Each lap should be approximately 7-10 seconds per lap faster than the previous lap. The goal is to have the tire temperature as high as possible on the last lap without "shocking" the tire during the warm-up laps. In essence, no wheelspin, late braking, or sliding. The last lap should be at, or very close, to the maximum possible.
After completing the initial heat cycle detailed above, the length of time the tire is allowed to rest out of service is possibly most important. The barest minimum for this process to be beneficial is 24 hours (not "the next day"). Any less than this is a waste of time. The best situation would allow a week before using the tire again. The tires should be removed from the vehicle while they cure, or the vehicle lifted to remove its weight from resting on the tires.
Proper tire management is a difficult process. The payoff is greatly increased competitive tire life.
A6 Autocross: For autocrossing, the A6 does not need the same break-in procedure as the R6. The A6 needs a minimal scuff-in session before the first autocross run. This "session" can comprise of simply driving around the event site at minimal speeds on the A6 set of tires. By scrubbing off the newness of the tread (only minimal or no shine remaining) prior to your first competitive run, the A6 tires will be more consistent in handling, grip and responsiveness on the first run. If this is not completed, running on un-scuffed A6 tires on your first run may result in the tires not gripping properly, or feeling like they "skate" over the course surface. It is acceptable to run 3 - 5 psi higher when scuffing in a new set of A6 tires, but be sure to reset them to the correct operating pressures before your first autocross run. As you compile autocross runs on your new A6 tires, they should become more consistent in run times.
Tire Pressure Recommendations for Competition
Traditionally, Hoosier tires have often required higher pressures than other brands. This has changed with the A6/R6.
Roadrace/Track Applications
Vehicle
Size Recommended
Hot Pressure Cold
Pressure
1800-2200 lbs 34-37+ 26-31
2200-2600 lbs 35-38+ 27-32
2600-3000 lbs 37-41+ 27-32
over 3000 lbs 38-43+ 27-33
+ Higher pressures will improve the performance capability but will require a more sensitive feel to take advantage of the increase.
One characteristic of the tires is the tendency to "skate" initially (when inflation pressures are correct). It is important to resist lowering the pressure to attempt to eliminate this feeling. Dropping the pressure too far may improve the "feel" of the tire however it will also lower the performance and increase the wear rate.
Autocross Applications
For autocross applications, your starting pressure for the first run should be within 1-2 psi of the recommended hot pressures shown above. After the first run and each subsequent run, keep resetting the pressures back to your target hot pressures before taking the next run. This way your tires are at the proper pressure during the bulk of every run you take.
Tire Temperature Recommendations
For best performance the expected temperature range will vary from track to track. Generally, optimum traction will be generated when the pit lane temps show 180-200 degrees for the R6 in Roadrace applications, and 140-150 degrees for the A6 in an Autocross application.
Chassis Setup Recommendations
For optimum performance the tires will require around 3 degrees of negative camber. There will be a trade-off in maximum performance to maximize wear. Generally 1/2 degree less than optimum will result in the best compromise for wear and speed. Less than 2.5 degrees can result in excessive wear on the shoulder junction.
The tires should offer better performance with spring/shock rates that are higher than previous brands you may have run.
Things to Consider
These tires are molded to their designed tread depth. They do not require shaving to be prepared for competition use. Shaving the tire further will not improve performance. It is not recommended that they be altered in this manner.
Due to extremely light construction, the Hoosier tires have a much lower polar moment than many other radial tires. This translates to a very low rotational mass, which is a good thing for performance applications. The down side to this feature is that the tires don't resist "spikes" in braking force as well as a heavier tire might. As a result, there is a tendency for drivers to "flatspot" a tire the first time really getting to the limit. Vehicles equipped with ABS will benefit from its use. If you do not use ABS, it is recommended that you make an effort to minimize stabbing the brakes until you have some experience with the feel of the tire under hard braking.
The light construction also provides less protection from impact damage and punctures. Off-course excursions or running over debris on the track will likely result in tire damage.
These tires are not directional or asymmetrical. Once some wear has occurred it may be desirable to flip the tire on the wheel so a "fresh" shoulder now faces outward in order to even out the wear and maximize tire life.
Following the recommended break-in procedure will require a lot of planning to make it work. The benefits to doing it right include greatly increased tire life as well as more consistent performance and durability under stress.
The Hoosier D.O.T. Radial tires are extremely good in dry conditions, however they don't make very good wet weather tires. Having dedicated rain tires available will be necessary for your team to be properly prepared. Hoosier makes a D.O.T.-approved wet tire called the D.O.T. Radial Wet that has been proven to be superior at full tread depth in steady "wet" conditions. This tire can also be shaved to partial tread depth for use as an intermediate wet tire.
01-21-2008, 07:16 AM
#3
When I started feeling some extra oversteer and extra slide with my 710's I assumed they were on their way out and called Tirerack for new ones. I had at least 100 dry autocross runs on them, and they were not near the cords, but grip was starting to be less predictable. Since there was tread, I was wondering if it was the cooler weather, or if the tires were timing out on grip from all the runs. Tirerack said every time you drive on the 710's you are using up a tiny bit of the moisture in the tire, and that chisels away at the grip. Even if you aren't reaching high temps, you are probably wearing out the tire anyway.
01-21-2008, 12:03 PM
#4
A 100 runs sounds like a heck of a lot to me but, I haven't autocrossed in many years. Your tread depth is no indication on how well the tire will perform and the tires can be worn out with tread still showing. i have a large pile of slicks beside my shop that still show good depth on the tread indicators but are worthless on the track.
The more heatcycles you put on your tires, the longer they take to come back in. And this does make it tough for autocross. For example, on our roadrace slicks, a tire with 2 or 3 heatcycles will come up to temp and achieve good grip in 2 laps. A tire with 6 to 7 HC's may take 4 to 5 laps to start feeling right. After 8 HC's, the tires are only used for practice. This is for roadrace but applies to autocross too, not necessaraly the number of cycles but the way the tires go away.
And considering that when you autocross, the tires are getting heat shocked on every run v.s. on a roadrace, we warm up the tires slowly on a pace lap.
One thing I do notice is that tires that are broken in correctly retain their grip longer than tires that are hammered right away.
The more heatcycles you put on your tires, the longer they take to come back in. And this does make it tough for autocross. For example, on our roadrace slicks, a tire with 2 or 3 heatcycles will come up to temp and achieve good grip in 2 laps. A tire with 6 to 7 HC's may take 4 to 5 laps to start feeling right. After 8 HC's, the tires are only used for practice. This is for roadrace but applies to autocross too, not necessaraly the number of cycles but the way the tires go away.
And considering that when you autocross, the tires are getting heat shocked on every run v.s. on a roadrace, we warm up the tires slowly on a pace lap.
One thing I do notice is that tires that are broken in correctly retain their grip longer than tires that are hammered right away.
