Tech Session follow up - part 2: Hoosier tire care & feeding
Posted: Thu Jun 21, 2012 6:19 pmThis is all copied from the Hoosier site (sorry about the weird cap no cap type) 
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
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 temp 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 a lap faster than the previous lap. The goal is to have the tire temp 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,
the maximum possible.
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 (no or minimal shininess
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. You are welcome to run 3 - 5
psi higher when scuffing in a new set of A6’s, 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’s, they should become more consistent in run times.
“Cure” Time
After completing the initial run phase, the length of time the tire is allowed to set is possibly more 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.
Proper tire management is a difficult process. To accomplish this almost always requires a second set of wheels. The payoff is greatly increased competitive 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
consistent performance and durability under stress. Please make an effort to educate your team on the importance of this. It can save you a lot of money.
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 110-140 degrees for the A6 in an Autocross application.
Note: Use of static infra-red pyrometers is an inaccurate method to monitor tire temps.
ChASSIS SETuP RECOmmENdATIONS
For optimum performance the Hoosier P-Metric radial tires require about 3 degrees of camber. There will be a trade off in maximum performance to maximize wear.
Generally, 1/2 degrees 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 Hoosier tires typically offer better performance with spring/shock rates higher than previous brands you may have run.
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..................30-33+...................................22-27
2200-2600 LBS..................31-34+...................................23-28
2600-3000 LBS..................33-37+...................................23-28
OVER 3000 LBS.................34-39+....................................23-29
+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.
Banked Oval / Road Courses
On these type of course configurations, the loaded side tires should be elevated four (4) psi (hot) above the normal road course pressure
recommendations.
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.
The above chart is a general recommendation which is intended for a standard configuration vehicle (i.e. front engine, rear wheel drive).
Factors which can radically affect your pressure set up would include front wheel drive, independent rear suspension, rear engine, McPherson
vs. control arm front suspension.
FRONT WhEEL dRIVE
Vehicles configured with FWD are probably the most difficult application for a tire setup. The combination of steering, braking and accelerating
on the front tires, combined with higher corner weights for the front positions produce a harsh environment for the tire. These vehicles will
typically have a strut type of suspension which limits camber gain. All these factors result in conditions which require the tire do more work
than a simple chart for pressures can accommodate.
In severe cases front tire pressures for FWD vehicles can run in the 48-52 psi (hot). In cases where the tire size is limited to a relatively
small tire, the required pressure can run even higher. The front to rear pressure differential on FWD cars can have extreme ranges of
inflation, depending on the driver preference, suspension tuning, and track configuration.
Independent rear suspension
With IRS and proper geometry up front, tire pressures can be reduced from the recommendations listed above. When there is adequate
camber gain and good roll control, the Hoosier radial tire will perform very well at the reduced air pressure. This results in a bigger
“sweet spot” and easier control at the limit.
When tuning at reduced pressures use the following formula to determine the minimum safe pressure: Divide the total vehicle weight, including
fuel and driver, by 100 to arrive at the minimum safe pressure. Example: Your car weighs 2750 lbs. as raced. The minimum safe (cold)
pressure is 27.5 psi.
Extreme care should be taken when tuning at reduced pressure. Tire damage can occur that is not visible to external inspection.
Vehicles equipped with independent rear suspension (IRS) have a distinct advantage over non-IRS cars when using radial tires. This is true for two
reasons. First, it is possible to setup some amount of static negative camber on IRS suspensions, if needed. Second, the IRS geometry can provide
the proper camber gain to achieve the dynamic camber needed for a radial tire. This is a great benefit because it then becomes possible to better
address front tire grip when the rear of the car can be optimized closer to the tire’s potential.
NO WARRANTY POLICY
hOOSIER RACING TIRE CORP. offers racing tires for sale only upon the conditions and the terms contained in this disclaimer of liability and indemnity. Due to many varied and
different conditions which Hoosier Racing Tires and Tubes are exposed and because of the manner in which racing is conducted, Hoosier Racing Tire Corp. makes absolutely no
warranty, expressed or implied, as to the fitness for a general or particular purpose or of merchantability in connection with any offer of sale of Hoosier Racing Tires and tubes.
“hOOSIER RACING TIRES AND TUBES ARE SOLD AS IS.” Race tires are not tested or labeled to meet FMVSS 109, 119, 139 or ECE36 Safety Standards. Therefore it is dangerous
and illegal to sell race tires for use on public highways. Any person selling Hoosier Racing Tires or Tubes for highway use agrees to indemnity and reimburse Hoosier Racing Tire
Corp. for all loss, damage, or liability Hoosier Racing Tire Corp. may suffer because of such sales. Not applicable where prohibited by law. Not following these warnings can cause
SERIOUS PERSONAL INjURy OR DEATh. For more information read tire labels, follow manufacturer’s warnings as molded in tire sidewalls and visit hoosiertire.com.
SERVICE LIFE
Service Life for Race Tires: Old tires can fail in use, causing loss of vehicle control and personal injury. Environmental conditions like temperature extremes, exposure to sunlight,
electric arc, solvents, automotive fluids, and atmospheric pollutants accelerate the aging process. Hoosier Racing Tire strongly recommends that new (sticker) tires should be put
in service within 2 years of date of purchase. Used (scuffed) tires have a shorter service life than new (sticker) tires. Poor storage and infrequent use accelerate the aging process.
ThINGS TO CONSIdER
These tires are molded to their designed tread depth. They do not require shaving to be prepared for competition use.
Due to extremely light construction, Hoosier tires have a much lower polar moment than 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 do not 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.
Once some wear has occurred it may be desirable to flip the tire on the wheel in order to even out the wear and maximize tire life.
Wheel Widths
Wheel width dramatically affects wear and performance of the Hoosier P-Metric radial tires.
There is about a one inch window of optimum width. The trick is to figure out that window. A good rule of thumb to use for determining proper width
is to use the tread width of the tire. Measure the tread width. Plus or minus 1/2 inch from the tread dimension will indicate the proper rim sizing. It is
possible to use narrower wheels, but at a sacrifice to shoulder wear and cornering power.
“Measured” rim vs. “Recommended” rim
In our printed product catalog and on our website tire specifications you will see two columns of information regarding rim dimensions. In most
cases, the “measured rim” and the “recommended rim” will be the same. However in the case of DOT tires, the information may appear contradictory.
The reason for the differences lies in the Department of Transportation requirements for publishing tire dimensions on any tire that carries a DOT
certification. Each tire size has a specific rim that must be used when taking measurements for tire comparison. This is intended to allow consumers
a consistent way to compare tire sizes between brands.
With respect to the Hoosier P-Metric line, the recommended rim size will typically be wider than the DOT standardized wheel.
The fact that a tire will “fit” on a rim is not an indication that it will work effectively in that condition. Radial tires are extremely sensitive to wheel
widths. The performance characteristics of the tire can change significantly within the recommended range of application. Mounting a tire on a rim
that is outside of the recommendation is not a good idea.
Driving Style/Braking
Driving style has also shown to significantly effect tire wear. Drivers who achieve their speed by “tossing” the car run the risk of increased tire wear.
Radial tires develop their highest cornering power at relatively low slip angles. Smooth, tidy driving yields faster lap times and better tire wear.
The braking feel of the Hoosier R6 tire is very vague at the threshold. This is particularly true for “sticker” tires. Drivers need to develop a sensitivity
for the limits under braking. This takes time and practice. Failure to apply this will result in flatspotted tires.
Particular care needs to be taken when selecting brake pad compounds. It is possible to have a pad that is too aggressive. This will make it very difficult
to develop good braking feel for threshold braking.
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
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 temp 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 a lap faster than the previous lap. The goal is to have the tire temp 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,
the maximum possible.
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 (no or minimal shininess
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. You are welcome to run 3 - 5
psi higher when scuffing in a new set of A6’s, 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’s, they should become more consistent in run times.
“Cure” Time
After completing the initial run phase, the length of time the tire is allowed to set is possibly more 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.
Proper tire management is a difficult process. To accomplish this almost always requires a second set of wheels. The payoff is greatly increased competitive 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
consistent performance and durability under stress. Please make an effort to educate your team on the importance of this. It can save you a lot of money.
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 110-140 degrees for the A6 in an Autocross application.
Note: Use of static infra-red pyrometers is an inaccurate method to monitor tire temps.
ChASSIS SETuP RECOmmENdATIONS
For optimum performance the Hoosier P-Metric radial tires require about 3 degrees of camber. There will be a trade off in maximum performance to maximize wear.
Generally, 1/2 degrees 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 Hoosier tires typically offer better performance with spring/shock rates higher than previous brands you may have run.
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..................30-33+...................................22-27
2200-2600 LBS..................31-34+...................................23-28
2600-3000 LBS..................33-37+...................................23-28
OVER 3000 LBS.................34-39+....................................23-29
+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.
Banked Oval / Road Courses
On these type of course configurations, the loaded side tires should be elevated four (4) psi (hot) above the normal road course pressure
recommendations.
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.
The above chart is a general recommendation which is intended for a standard configuration vehicle (i.e. front engine, rear wheel drive).
Factors which can radically affect your pressure set up would include front wheel drive, independent rear suspension, rear engine, McPherson
vs. control arm front suspension.
FRONT WhEEL dRIVE
Vehicles configured with FWD are probably the most difficult application for a tire setup. The combination of steering, braking and accelerating
on the front tires, combined with higher corner weights for the front positions produce a harsh environment for the tire. These vehicles will
typically have a strut type of suspension which limits camber gain. All these factors result in conditions which require the tire do more work
than a simple chart for pressures can accommodate.
In severe cases front tire pressures for FWD vehicles can run in the 48-52 psi (hot). In cases where the tire size is limited to a relatively
small tire, the required pressure can run even higher. The front to rear pressure differential on FWD cars can have extreme ranges of
inflation, depending on the driver preference, suspension tuning, and track configuration.
Independent rear suspension
With IRS and proper geometry up front, tire pressures can be reduced from the recommendations listed above. When there is adequate
camber gain and good roll control, the Hoosier radial tire will perform very well at the reduced air pressure. This results in a bigger
“sweet spot” and easier control at the limit.
When tuning at reduced pressures use the following formula to determine the minimum safe pressure: Divide the total vehicle weight, including
fuel and driver, by 100 to arrive at the minimum safe pressure. Example: Your car weighs 2750 lbs. as raced. The minimum safe (cold)
pressure is 27.5 psi.
Extreme care should be taken when tuning at reduced pressure. Tire damage can occur that is not visible to external inspection.
Vehicles equipped with independent rear suspension (IRS) have a distinct advantage over non-IRS cars when using radial tires. This is true for two
reasons. First, it is possible to setup some amount of static negative camber on IRS suspensions, if needed. Second, the IRS geometry can provide
the proper camber gain to achieve the dynamic camber needed for a radial tire. This is a great benefit because it then becomes possible to better
address front tire grip when the rear of the car can be optimized closer to the tire’s potential.
NO WARRANTY POLICY
hOOSIER RACING TIRE CORP. offers racing tires for sale only upon the conditions and the terms contained in this disclaimer of liability and indemnity. Due to many varied and
different conditions which Hoosier Racing Tires and Tubes are exposed and because of the manner in which racing is conducted, Hoosier Racing Tire Corp. makes absolutely no
warranty, expressed or implied, as to the fitness for a general or particular purpose or of merchantability in connection with any offer of sale of Hoosier Racing Tires and tubes.
“hOOSIER RACING TIRES AND TUBES ARE SOLD AS IS.” Race tires are not tested or labeled to meet FMVSS 109, 119, 139 or ECE36 Safety Standards. Therefore it is dangerous
and illegal to sell race tires for use on public highways. Any person selling Hoosier Racing Tires or Tubes for highway use agrees to indemnity and reimburse Hoosier Racing Tire
Corp. for all loss, damage, or liability Hoosier Racing Tire Corp. may suffer because of such sales. Not applicable where prohibited by law. Not following these warnings can cause
SERIOUS PERSONAL INjURy OR DEATh. For more information read tire labels, follow manufacturer’s warnings as molded in tire sidewalls and visit hoosiertire.com.
SERVICE LIFE
Service Life for Race Tires: Old tires can fail in use, causing loss of vehicle control and personal injury. Environmental conditions like temperature extremes, exposure to sunlight,
electric arc, solvents, automotive fluids, and atmospheric pollutants accelerate the aging process. Hoosier Racing Tire strongly recommends that new (sticker) tires should be put
in service within 2 years of date of purchase. Used (scuffed) tires have a shorter service life than new (sticker) tires. Poor storage and infrequent use accelerate the aging process.
ThINGS TO CONSIdER
These tires are molded to their designed tread depth. They do not require shaving to be prepared for competition use.
Due to extremely light construction, Hoosier tires have a much lower polar moment than 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 do not 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.
Once some wear has occurred it may be desirable to flip the tire on the wheel in order to even out the wear and maximize tire life.
Wheel Widths
Wheel width dramatically affects wear and performance of the Hoosier P-Metric radial tires.
There is about a one inch window of optimum width. The trick is to figure out that window. A good rule of thumb to use for determining proper width
is to use the tread width of the tire. Measure the tread width. Plus or minus 1/2 inch from the tread dimension will indicate the proper rim sizing. It is
possible to use narrower wheels, but at a sacrifice to shoulder wear and cornering power.
“Measured” rim vs. “Recommended” rim
In our printed product catalog and on our website tire specifications you will see two columns of information regarding rim dimensions. In most
cases, the “measured rim” and the “recommended rim” will be the same. However in the case of DOT tires, the information may appear contradictory.
The reason for the differences lies in the Department of Transportation requirements for publishing tire dimensions on any tire that carries a DOT
certification. Each tire size has a specific rim that must be used when taking measurements for tire comparison. This is intended to allow consumers
a consistent way to compare tire sizes between brands.
With respect to the Hoosier P-Metric line, the recommended rim size will typically be wider than the DOT standardized wheel.
The fact that a tire will “fit” on a rim is not an indication that it will work effectively in that condition. Radial tires are extremely sensitive to wheel
widths. The performance characteristics of the tire can change significantly within the recommended range of application. Mounting a tire on a rim
that is outside of the recommendation is not a good idea.
Driving Style/Braking
Driving style has also shown to significantly effect tire wear. Drivers who achieve their speed by “tossing” the car run the risk of increased tire wear.
Radial tires develop their highest cornering power at relatively low slip angles. Smooth, tidy driving yields faster lap times and better tire wear.
The braking feel of the Hoosier R6 tire is very vague at the threshold. This is particularly true for “sticker” tires. Drivers need to develop a sensitivity
for the limits under braking. This takes time and practice. Failure to apply this will result in flatspotted tires.
Particular care needs to be taken when selecting brake pad compounds. It is possible to have a pad that is too aggressive. This will make it very difficult
to develop good braking feel for threshold braking.