mickey thompson tire info

PittSpeed Automotive
1

since this has become a popular tire, figured post up some info on them

Proper use of Mickey Thompson ET Street Radial

Inflation Pressures

On the racetrack DO NOT use starting pressures below 11 psi.
Recommend pressures for:

P295 and larger sizes: 11-14 psi
P275 and smaller sizes: 12-16 psi

On the highway we recommend running 75% of the max psi as notes on the sidewall of the tire.

Burnouts

The tread compound used in the ET Street Radials is designed to heat quickly and does not require a heavy burnout. Continue the burnout until the engine starts to pull down. We do not recommend a dry hop after the burnout.
Bead/Wheel Slippage

Some bead/wheel slippage may result during the course of a 1/4 mile (or 1/8 mile) drag race. This is normal.

Use of Bead Screws

If you elect to use bead screws, we recommend the installation of 16 equally spaced screws per bead.

Bead-Lock Wheels

For drag strip speeds in excess of 180 mph, Bead-lock wheels are highly recommended.

This is Mickey Thompson STREET & STRIP TECH BULLETINS Technical Bulletin #7. For more information regarding Mickey Thompson Performance Products ph: 330.928.9092

2

DRAG SLICK COMPOUND, ROLLOUT, AND BURNOUT SPECIFICATION SHEET

CURRENT COMPOUND SELECTION AND APPLICATION GUIDE
The compound number can be found in the serial number on each tire.
EXAMPLE: CY1J M5 FJ087 M5-Compound code.

Mickey Thompson tires are compounded by size and application. The following points are general application suggestions. Mickey Thompson is not responsible for misapplications.
The catalog number suffix indicates a construction, size or compound enhancement for particular applications.

ST= Suggested for manual transmission (Medium compound)
W= Extra tread width (please note actual tread and section width on spec sheet)
S= Stiff sidewall construction. Recommended for 4 link suspension cars, heavy cars (over 3000lb.) ,and “soft ride” Rear Engine Dragsters. Aids in quicker reaction time due to less tire distortion.

MICKEY THOMPSON COMPOUND SELECTION CHART
Medium--------------------------------------------------Soft
B1 M7 M5 R2 R1 L8 L7 M9 B2 L4 M2

B1- For motorcycles.
B2- For motorcycles.
L4 - Soft compound for Dragsters, lightweight vehicles and vehicles without rear suspension.
L7- For motorcycles.
L8- Good compound for general use.
M2- For Jr. Dragsters.
M5- Good compound for general use.
M7- Good compound for general use.
M9- Aggressive compound for heavy cars, 3000lbs+
R1- Special Compound for ET Drag Radial.
R2- Special Compound for ET Street Radial.

MICKEY THOMPSON NATURAL RUBBER RACING TUBES
Besides being required for air retention, Mickey Thompson racing tubes will enhance the reaction time, increase stiffness and reduce sidewall shock and deflection when launching.
Note: Always run the correct size tube for the application, the wrong tube will always fail.

ROLLOUT (CIRCUMFERENCE)
Always check the rollout (circumference) of tires when they are first mounted to see if they are within ¾" of each other. The tires must be matched before they are run. This can be done by over inflating the shorter tire and letting it sit a short period of time to allow it to stretch. It is very important to monitor this procedure to avoid stretching too much. Never inflate tires over 40 PSI to stretch them.
Note: This procedure will only work before a tire has been used.

BURNOUTS- FOR MOST APPLICATIONS

  1. First pass of the day hard burnout. After that follow general guidelines of #2 and #3 stated below.

  2. Automatic transmissions and Softer compounds: First pass or two, fairly hard burnout, after that a light burnout should be sufficient.

  3. Standard transmission “Stockers”: No burnout or short, dry burnout. Super Stock and Comp cars- light burnout, haze tires and stage immediately.

This is Mickey Thompson DRAG / STREET Technical Bulletin #1.
For more information regarding Mickey Thompson Performance Products ph: 330.928.9092

3

ET STREET™ AND ET DRAG®
AIR PRESSURE GUIDELINES

PROPER AIR PRESSURE
Proper air pressure is critical to the best performance of your ET Drag or ET Street racing tires. Recommending air pressure is not easy, since there are so many variables that affect it: i.e. weight distribution, transmission, chassis set-up, wheel size, etc. To help you, we have broken down the types of vehicles into the following six categories with a recommended starting point for the correct air pressure. Keep in mind that these are only starting points. Actual optimum air pressure may vary significantly. If you have been running another brand of slick on your racecar, we generally recommend you start with the same air pressure you were running and go up in ½ pound increments until you get the best performance. Most racers will usually end up with ½ to 2 pound more air pressure in a Mickey Thompson tire.
Note: Many racers feel that “Less is Better” with regard to air pressure. This is not always the case. While there are exceptions to every rule, we have found higher pressure generally works best with Mickey Thompson Tires. Not only do the higher pressures lead to quicker times, but they also contribute to a safer, more stable ride at the finish line.

ET DRAG® AND ET STREET™

VEHICLE WEIGHT

TIRE SIZE

AIR PRESSURE

UNDER 2,500 POUNDS
UNDER 2,500 POUNDS

UNDER 30" DIAMETER
OVER 30" DIAMETER

6 P.S.I. AND UP
4 P.S.I. AND UP

2,500 TO 3,000 POUNDS
2,500 TO 3,000 POUNDS

UNDER 30" DIAMETER
OVER 30" DIAMETER

8 P.S.I. AND UP
6 P.S.I. AND UP

OVER 3,000 POUNDS
OVER 3,000 POUNDS

UNDER 30" DIAMETER
OVER 30" DIAMETER

16 P.S.I. AND UP
10 P.S.I. AND UP

ET DRAG RADIAL

UNDER 2,500 POUNDS
UNDER 2,500 POUNDS

UNDER 30" DIAMETER
OVER 30" DIAMETER

16 P.S.I. AND UP
12 P.S.I. AND UP

2,500 TO 3,000 POUNDS
2,500 TO 3,000 POUNDS

UNDER 30" DIAMETER
OVER 30" DIAMETER

16 P.S.I. AND UP
12 P.S.I. AND UP

OVER 3,000 POUNDS
OVER 3,000 POUNDS

UNDER 30" DIAMETER
OVER 30" DIAMETER

16 P.S.I. AND UP
12 P.S.I. AND UP

When working with ET Drag Radials use 1 psi adjustments to see change.
A radial will perform quicker the more air you can run.
The burn out should begin once the rear tires are completely out of the water box.

ET DRAG MOTORCYCLE

MCR² (3295): Quarter Mile in 7 seconds, Turbo Bikes, 6 - 10 psi

Quarter Mile: in 8 to 9 seconds, 15 – 19 psi

Quarter Mile: High 9 seconds and slower, high twenties to mid thirties

MCR (3299): Quarter Mile up to 9 seconds, 25 + psi

Stock or piped and jetted bikes, high twenties to high thirties

3053M (Pro Stock – Pro Mod): 4.0 – 6.0 psi, wheelie bar 2” - 2 1/8”

3064M: 4.0 – 6.0 psi, Wheelie bar 2” - 2 1/8”

3065M: 6.0 – 9.0 psi, Wheelie bar 1 ¾”

3073M: 7.0 – 8.0 psi, Wheelie bar 1 ¾”

3220: 7.5 – 10 psi, Wheelie bar 2” - 2 1/8”

3221: 6.5 – 8.0 psi, Wheelie bar 2” - 2 1/8”

3222: 6.5 – 8.0 psi, Wheelie bar 2” - 2 1/8”

These recommended pressures are guidelines only, actual pressures may vary.

Wheelie bar settings are guidelines only, with the front end extended and can vary

ET STREET RADIAL

On the racetrack DO NOT use starting pressures below 11 psi.

Recommend pressures for:

P295 and larger sizes: 11-14 psi

P275 and smaller sizes: 12-16 psi

On the highway we recommend running 75% of maximum psi stated on the sidewall of the tire.

ET DRAG JR.

3621: 4 – 8 psi

3644: 4 – 8 psi

Mickey Thompson also recommends that you invest in a good tire pressure gauge and that you keep accurate and complete records of each pass. This will aid you in becoming a consistent performer.

This is Mickey Thompson DRAG / STREET Technical Bulletin #3.
For more information regarding Mickey Thompson Performance Products ph: 330.928.9092

4

ET DRAG® AND ET STREET™
TIRE SCREW MOUNTING PROCEDURE ON NEW RIMS

MOUNTING PROCEDURES FOR TUBE TYPE TIRES

  1. Begin by Drilling 12 equally spaced holes on both the inner and outer flange of the rim. Drill the holes so that one hole goes straight into the rim and the next hole goes into the rim flange at a 45 degree angle (see diagram #1).
    Note: (Mickey Thompson strongly suggests that you use Drag slick mounting screws only, and that you follow the rim screw manufacturers suggested drill bit size.)

  2. Trial run the screws through all 24 holes. Running screws in the hole and back out again.

  3. Check for any sharp edges that the screw may have pushed out or caused during the trial run through. If any sharp edges are found debur and make sure rim is smooth and clean.

  4. Mount tire and tube. Have professional install the tire and tube on proper equipment or see Mickey Thompson tech bulletin #2 for help.

  5. Inflate the wheel and tire assembly to 20 psi.

  6. Install screws into wheel and tire assembly. Deflate assembly to operating pressure. Inspect rim flange and bead area for proper bead seating. If bead is not fully seated, reinflate and reinstall screws.

  7. Static balance or “Bubble Balance” the assembly once screws are installed.

  8. Periodically you should check the wheel for loose screws and inspect the rim bead area to be sure that there is no bead area separation.
    Note: It would be good practice to inspect after each pass when you are checking your air pressure.

This is Mickey Thompson DRAG / STREET Technical Bulletin #4.
For more information regarding Mickey Thompson Performance Products ph: 330.928.9092

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5

MICKEY THOMPSON® ET DRAG® AND ET STREET™
EXTENDED STORAGE OR WINTER STORAGE

STORAGE PROCEDURES AND TIPS
During the winter months or whenever tires are being stored for long periods of time, the following tips and guidelines should be followed to help extend the life of Mickey Thompson ET Street or ET Drag tires.

  1. Remove the tires from the car or jack the car up to remove the load.

  2. Drop air pressure to 5 pounds.

  3. Keep the tires away from direct light (sun or fluorescent). It is best to keep tires covered.

  4. Keep tires away from electric motors I.E. furnace, air compressor, etc. These create OZONE, which will damage the tire.

  5. Mickey Thompson suggests that you keep tires away from extreme high and low temperatures.

  6. Do not use any chemicals on the tires. To clean them use a mild detergent and water. Rinse well. Do not clean the tread surface.

By following these simple precautions you will get the best service from your tires. If you experience inconsistent 60’ & 330’ times the next season, it’s probably time to replace the tires.

This is Mickey Thompson DRAG / STREET Technical Bulletin #5.
For more information regarding Mickey Thompson Performance Products ph: 330.928.9092

6

TUBES AND TUBE TYPE TIRES

When buying tube type tires it is important to understand the reasons behind making a tire tube type and when it is appropriate to run the tire with or without a tube. The following information will help in the decision making process.

  1. Air retention
    Tube type tires are not guaranteed to hold air without a tube. If a tube type tire leaks, it is not defective. There is a liner molded into the carcass of a tire that seals it and makes it tubeless. This liner is intentionally omitted from racing tires. This is done primary for weight purposes. More on that later.

  2. Consistency
    Without a tube you cannot maintain consistent air pressure. Even the slightest leakage will cause a difference in the performance of the tire. Therefore if consistency is the primary goal, as in Bracket Racing, a tube should always be used.

  3. Strength
    The wrinkling of the sidewall that is visible at launch causes the carcass material in the tire to break down over time. The more violent the launch the quicker this break down occurs. Inconsistent 60’ times or a drop off of 60’ times usually indicate that this is happening. When this happens the tires should be replaced, regardless of the amount of tread rubber remaining. The use of tubes strengthens the sidewall of the tire and keeps this breakdown from happening prematurely, therefore extending the life of the tire. This will save money in the long run.

  4. Weight & performance
    In some cases it is acceptable to run a racing tire without a tube. When a car competes in a heads up class, unsprung weight is an important factor. Tires and tubes are all unsprung weight. One pound of “unsprung” weight is equal to 8 pounds of “sprung” weight. The average tube weighs about 6 pounds. Therefore, if you eliminate the tubes you have eliminated the equivalent of 96 pounds from the car. For every 10 pounds of unsprung weight removed you may pick up as much as .01 seconds in quarter mile ET.

  5. Cost
    All natural rubber tubes are expensive. All M/T tubes are made of Natural Rubber and feature a clamp down valve stem. There are some inexpensive Butyl rubber tubes on the market. Even some with clamp down valve stems. Natural rubber is, by far, the better choice. It conforms to the wrinkles better. Dissipates heat better. And it doesn’t get brittle like butyl does. Therefore M/T natural rubber tubes offer superior performance and will last far longer.

  6. Safety
    At a racetrack you must check air pressure regularly. This is important to maintain performance and to insure pressures are not too low. Low pressure can be dangerous.
    Never run tube type tires on the street without a tube. Leakage and the prolonged heat build up can lead to tire failure and serious injury or death. This is not a matter to take lightly.

THE BOTTOM LINE
THE DECISION TO RUN WITH OR WITHOUT TUBES SHOULD ALWAYS BE BASED ON SAFETY AND PERFORMANCE. NOT COST!

This is Mickey Thompson DRAG / STREET Technical Bulletin #6.
For more information regarding Mickey Thompson Performance Products ph: 330.928.9092 OR 909.587.0101

7

PROPER MEASUREMENT OF OVERALL DIAMETER (O.D.),
STATIC LOADED RADIUS (S.L.R.) AND CIRCUMFERENCE

Proper measurement of a tire is very important when choosing a tire as it will affect many things such as engine r.p.m., vehicle fitment, roll out and ground clearance issues.

Overall Diameter (O.D.)

O.D. is the measurement of a tire diameter and is taken from the top of the tire to the bottom of the tire. Note: The O.D. of a tire is measured with the tire off of the vehicle, not under load and at appropriate air pressure. Knowing the O.D. of a tire will aid you in fitment issues and can assist you in gear ratio and speedometer corrections.

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Circumference

Circumference can be calculated in a scientific manner using this formula . . . Circumference = p (or 3.1416) x O.D. Example: A 28" x 10.5" x 15 drag slick that has an O.D. of 27.8" on an 11" rim has a circumference of 87.29". 27.8 x p (or 3.1416) = 87.29" Or 87.29" of what drag racers call roll out.

Roll out is the number of inches the tire rolls before it has traveled back to its initial starting point.

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A tire can be measured for circumference or roll out by using a tape measure. Start by laying the mounted and inflated tire on its side. Wrap the tape measure around the tire going around the center part of the tread pattern.

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Note . . . Remember, for drive tires on a drag race application, it is important that the roll out or circumference match on both sides of the car. (This should be done before the car is ever run.) If you have two slicks that do not match, see drag tech bulletin #1 for the proper way to match a set of drive tires.

Static Loaded Radius (S.L.R.)
S.L.R. is a measurement that determines a tire’s overall diameter under load. This measurement is vehicle and application specific. It will aid in determining ground clearance and suspension clearances.

http://www.mickeythompsontires.com/images/ds-tb06_04.gif

There are many variables that affect the S.L.R. of a tire, such as tire construction, air pressure, vehicle weight and rim width, just to name a few.

All Mickey Thompson® tires are listed in our specification sheets with an O.D. (overall diameter) or circumference. These measurements are derived in the following manner . . .

M/T® Slicks: Measuring rim at 10 psi cold.
(Exception: 33" drag @ 6 psi)

M/T® Off Road and Street Tires: Measuring rim at max cold psi.

M/T® Baja Radial MTX’s: Measuring rim at max cold psi.

This is Mickey Thompson DRAG / STREET Technical Bulletin #8
For more information regarding Mickey Thompson Performance Products ph: 330.928.9092

8

MICKEY THOMPSON®
METRIC CONVERSION CHARTS

These charts were derived using the following conversion formula . . .

Example: 235/70R15
235 = Section width in millimeters

70 = Aspect ratio (ratio of section height to section width)

15 = Rim diameter

R = Radial Construction B = Bias Construction D = Bias Belted Construction

To calculate:
Tire Width: Section width divided by 25.4 (Ex: 235 / 25.4 = 9.25")

Section Height: Tire width times aspect ratio (Ex: 9.25" x 70% = 6.48")

Overall Diameter: Section height times 2 plus rim diameter (Ex: (6.48" x 2) + 15 = 27.96")

Therefore, a 235/70R15 is approximately 28" tall x 9.25" wide.

IMPORTANT
There are many variables that affect a tire width such as rim width, air pressure, sidewall constructions, etc. just to mention a few. Please feel free to use these charts as a guide only. If you are trying a custom fit and our tire looks like it may be a tight fit, contact the M/T® Tech Department and we will be happy to help you with your fitment issues.

13 INCH RIMS Section Width (inches) Overall Diameter (inches)
175/70R13 6.9 22.8
185/60R13 7.3 21.8
185/70R13 7.3 23.5
205/60R13 8.1 22.7
215/50R13 8.5 21.3
P175/70R13 6.9 22.6
P185/70R13 7.3 23.2
P195/60R13 7.7 22.1
P195/70R13 7.7 23.7
P205/60R13 8.1 22.6
P205/70R13 8.1 24.2
P215/60R13 8.5 23.1
P235/50R13 9.3 22.1

14 INCH RIMS Section Width (inches) Overall Diameter (inches)
185/60R14 7.3 22.8
185/70R14 7.3 24.2
195/60R14 7.7 23.2
195/70R14 7.7 24.9
205/70R14 8.1 25.7
215/60R14 8.5 24.2
225/60R14 8.9 24.7
235/60R14 9.3 25.2
P165/65R14 6.5 22.4
P185/70R14 7.3 24.2
P195/60R14 7.7 23.2
P195/70R14 7.7 24.7
P205/70R14 8.1 25.2
P215/60R14 8.5 24.1
P215/70R14 8.5 25.8
P225/60R14 8.9 24.5
P225/70R14 8.9 26.3
P235/60R14 9.3 25
P235/70R14 9.3 26.9
P245/50R14 9.6 23.7
P245/60R14 9.6 25.5
P265/50R14 10.4 25.5

15 INCH RIMS Section Width (inches) Overall Diameter (inches)
185/65R15 7.3 24.5
185/70R15 7.3 25.5
195/50R15 7.7 22.8
195/60R15 7.7 24.3
195/65R15 7.7 25
205/50R15 8.1 23.2
205/55R15 8.1 23.9
205/60R15 8.1 24.8
205/65R15 8.1 25.5
215/60R15 8.5 25.2
225/50R15 8.9 24
225/60R15 8.9 25.6
225/70R15 8.9 27.4
235/60R15 9.3 26.2
P205/65R15 8.1 25.5
P215/65R15 8.5 26.1
P215/70R15 8.5 26.8
P225/65R15 8.9 26.5
P225/70R15 8.9 27.3
P235/60R15 9.3 26.1
P235/65R15 9.3 27.1
P235/70R15 9.3 27.8
P245/50R15 9.6 24.8
P245/60R15 9.6 26.5
P245/65R15 9.6 27.5
P245/70R15 9.6 28.5
P255/60R15 10 26.9
P255/70R15 10 28.9
P265/50R15 10.4 25.6
P265/75R15 10.4 30.7
P275/50R15 10.8 25.7
P275/60R15 10.8 28
P285/70R15 11.2 30.8
P295/50R15 11.6 26.7

16 INCH RIMS Section Width (inches) Overall Diameter (inches)
205/55R16 8.1 25
225/50R16 8.9 25
245/45R16 9.6 24.8
P215/60R16 8.5 26.2
P225/60R16 8.9 26.6
P225/75R16 8.9 29.3
P235/65R16 9.3 26.1
P245/50R16 9.6 25.7
P245/75R16 9.6 30.5
P255/50R16 10 26.2
P265/75R16 10.4 32.9
P285/75R16 11.2 32.8
P315/40R16 12.4 25.9

17 INCH RIMS Section Width (inches) Overall Diameter (inches)
P245/40R17 9.6 24.7
P245/45R17 9.6 25.7
P255/45R17 10 26.1
P275/40R17 10.8 25.8
P285/35R17 11.2 24.9
P285/40R17 11.2 26
P315/35R17 12.4 25.8
P335/35R17 13.2 26.2

9

I’ll be running ET Street radials in the near future, so this post was real helpful. Thanks.