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 Post Posted: Mon Aug 27, 2007 11:44 pm 
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Here's one of the Hoosiers that were on the 68.

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Here's the tech sheet on the MTs:

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.


George


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 Post Posted: Tue Sep 04, 2007 10:59 pm 
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I'm going to take this on a bit of a tangent but I have been back and forth over whether to make a minor 4 link adjustment now versus getting a few runs with the new slicks.  I think it's pretty obvious as some of you guys have pointed out that I am hitting the tires pretty good on the launch and that was the case before the 60s started going away so I'm thinking that I just might go ahead make the adjustment now.

The question I have is this...which direction is more sensitive?  In other words if I go back an inch and down an inch from where I am now which is going to have the most effect?  Going down or back?  My thinking is the lowering of the IC an inch will be more reactive than the inch going back.  I'm just trying to get an idea of how the thing will react to the change.  I'm not moving it 1 inch back and down, that was to illustrate my question.  Right now I'm at 52.3" out, 6.6" up, and 70.8% anti-squat.  The change I'm looking at making will be 51.7" out, 4.9" up, and 52.9% anti-squat.  So I'll be going .6" back and 1.7" down from where I am now.  The 52.9% anti-squat will be a substantial lessening of the hit but I need to get the front up in the air some too.

Whaddaya think???

George


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 Post Posted: Wed Sep 05, 2007 8:33 am 
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Making the IC shorter isn't going to help get the front up.  Making it longer will though.

On my car I'm going to go out and down to see how that does.  I looked at the chart last night and if I  move both bottom bars down one hole on both ends I'll get to 52 something and 9 something with 79%.  My thought is that not hitting the tire as hard and making the front come up more will offset themselves but not load the tire as hard at the hit.

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 Post Posted: Wed Sep 05, 2007 9:32 am 
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Making the IC shorter will not help get the front up but making it lower will.  So that goes back to my original question, which, rephrased, would be will the 1.7" I'm going down more than offset the .6" I'm going back and help get the front up?  I want to kinda sneak up on this.  My next combination of holes would put me at 54" out and 2.7" up at around 27% anti-squat which is a more drastic change.  I just don't want to beat the wheelie bars to death and wind up unloading the rear tires.


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 Post Posted: Wed Sep 05, 2007 10:24 am 
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I guess if you move it you will find out but remember, we are only suppose to change ONE thing at a time when testing stuff!  Changing tires and 4 link will get you lost cuz you won't know which change made the difference, if any! =;

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 Post Posted: Wed Sep 05, 2007 10:51 am 
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Except that I know what it was doing before the 60s went away and it still needed less hit.  Soooo...I'm thinking with the new slicks that should put me back to that square and the 4 link would still need tweaking...I think. :-k


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 Post Posted: Tue Sep 25, 2007 6:20 am 
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As someone has mentioned, the static rear wheel loads are not the same as those experienced during launch. So, the best method for 4link adjustments would involve simulating the launch forces and measuring the wheel loads.

That to which I'm referring is a "traction dyno" and its description and use are to be found on Pages 4, 5, and 6 in the link below.

The idea is to load the chassis in the same way that the inertial force loads it as you launch. So, without even starting the engine, you can then measure wheel loads and adjust until you get what you want.

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 Post Posted: Tue Sep 25, 2007 7:27 am 
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Im no expert,

BuT,

George, you need tubes, MT goodyear and all of them say that heavier cars need stiffer side walls.

Tubes are actually a tire tuning device, you grab a tire, if its too soft a side wall you then add a tube, if its still wrinkling too much you then need to change too a stiffer side wall tire.

Check out this from MT
http://www.mickeythompsontires.com/tech.php?bulletin=s1

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 Post Posted: Tue Sep 25, 2007 1:27 pm 
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To a certain extent, The wrinkles on the side wall are going to be there. What's important is, as they say, where the tire meets the road.

If you really want to know what that tire is doing, a pyrometer is the answer. It can not only tell you if your tire pressure is right, it can tell you if your compound is right or if you have a misalignment even to a certain extent if your chassis is working well.

For Drag racing this will be a one time deal. When you know what pressures the tire and car like. it will generally stay there. If the traction goes away the tires may get hotter but they will do it at the same rate. For those that think a drop in tire pressure will help on a slick track, think of the loss of traction in the center of the tire patch due to lack of compliance. Less air in the tire, it don't press the center out as far.

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 Post Posted: Tue Sep 25, 2007 8:29 pm 
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I'm going to jack it up to 9 psi this Saturday and see what it does.  M/T says go up in 1/2 psi increments and that you may very well find that you need to be 2 psi over what you ran in "other" brands.  So I may find myself at 10 psi before it's all over with.  The pictures I have seen of the "ideal" launch shows 3-4 wrinkles from the 3 to about 5:30 position.  No wrinkles on the bottom and none on the back side of the tire.

Ken and I were having a conversation earlier tonight and the question came up about how much, if any, time is lost in the 60' due to tire wrap.  Does it affect it or is the wrap wrapped up so to speak before the timers are started?  What's you guys think???

George


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 Post Posted: Tue Sep 25, 2007 8:46 pm 
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Not sure of a loss in 60 ft, but I think it will have a bad effect on Reaction time.

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 Post Posted: Tue Sep 25, 2007 8:55 pm 
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Well, really in box racing, reaction time is a function of how much delay is in the box.  I agree that it will affect reaction time but all of that can be compensated for.  

George


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 Post Posted: Wed Sep 26, 2007 1:19 am 
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How do the 16 inch tires 60 in comparison? With less tire to wrap. Or how about a radial?


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