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Discussion Starter #1
I have been driving and occasionaly racing my '91 Stang on MT street radials for several years.
Last weekend I went to a race and put on new MT ET Drag Slick, 26 x 8.5-15 inflated to 13PSI. This was my first experience with drag slicks and it was rather scary.
The launch was good, much better than on ET streets. Approximately half way into the 1/4 mile my car began to wander on the track. It felt rather loose. I felt like getting off the throttle, but forced myself to go all the way.
This run brought me [email protected] and I was not feeling like taking another try.
This is the first run in my life when I seemed to have so little control over the direction my car was going in. When I run my regular MT ET streets at the same 13PSI the car goes straight as an arrow.
I would very much appreciate your comments and/or advice.
Thanks!
 

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What kind of front tires?

No fluid leaks? How was the track prep and weather? Rears balanced and true? Nothing broken?
 

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Are you running radial front tires? You should never mix bias ply slicks and radials. They react differently to the load from the car. Try running a dedicated race front tire. Do you have tubes in the slicks? A slick is going to tend to wander a bit more than a street tire. It's normal. But it shouldn't be all over the track. Tubes help a bit with the stability of a slick.
 

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Keep adding air. Run as much pressure as you can. Those sidewalls are SOOOOOO soft its going to feel like you are all over. I ran ET Streets (not the radial) at 12psi and it did the same thing. Its just the tire design.

Orrrr....Mr. Goodfastncheap up there might have sold me on set of Hoosiers. I didnt feel any wobble when I used his, car went straight and fast. My next set will probably be a Hoosier slick.
 

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Discussion Starter #6
What kind of front tires?

No fluid leaks? How was the track prep and weather? Rears balanced and true? Nothing broken?
In the front I have regular Pirellis 225/40-17.
No fluid leaks.
Weather was on the cool side 57*. This was not a real track. We don't have any around here. It was a closed stretch of road with decent asphalt pavement.
I couldn't get any shop to balance these drag slicks on Drag Star rims. They tried to use a ridiculous number of ballansing weights, but it didn't help. Balancing machines were going nuts with this set of wheels.
Car is in good order.

Are you running radial front tires? You should never mix bias ply slicks and radials. They react differently to the load from the car. Try running a dedicated race front tire. Do you have tubes in the slicks? A slick is going to tend to wander a bit more than a street tire. It's normal. But it shouldn't be all over the track. Tubes help a bit with the stability of a slick.
I do use tubes in the slicks.
I don't know if I can fit a dedicated race tire over the 13" Cobra brakes in the front.

Keep adding air. Run as much pressure as you can. Those sidewalls are SOOOOOO soft its going to feel like you are all over. I ran ET Streets (not the radial) at 12psi and it did the same thing. Its just the tire design.
What is a reasonable pressure range for a drag slick?
I was thinking that with 13 PSI I was on the high side. Was I wrong?
 

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If the drag radials are working and you feel more comfortable on them why switch? Also, next time around get the stiff sidewall slicks you will feel more stable on them.
 

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Discussion Starter #9
If the drag radials are working and you feel more comfortable on them why switch? Also, next time around get the stiff sidewall slicks you will feel more stable on them.
The reason I wanted to switch to drag slicks was to get better traction and be able to launch from higher RPM.
With my ET streets I do a burnout and then dump the clutch somewhere between 2500 rpm on a colder day and 3000 on a hot day. This way tires don't spin at launch and the car jumps forward. If I bring rpm any higher, tires will spin and I show a lousy time.
I was thinking designated drag slicks would give me a chance to launch from 3500 or so.
 

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I ran my M/T 26x8.5's at the track on 14psi and was running 116 and it felt like a Sunday drive. This was with 225/60/15 radials on the front.
During my street racing days, running slicks on the street, they would allways "wander" at high speeds. Yeah, it can get scary. I guess it is the highway surface that does it. On a Dragstrip they never would wander.
I wouldnt spend a great deal of time chasing this until you have tried them on a dragstrip. Chances are they wont do it on a proper racing surface.
As for balancing, all that is needed is a static balance( weights on inside). I have owned several sets that I could not dynamic balance. If all else fails, use a bubble balancer to balance them( Yes, they work).
 

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I ran a set of ET drags at 10psi and my car did the same thing. I put 20psi in them and it solved the problem. Start at 20psi and then drop 1psi per run until your happy.
 

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Steve, what is a run out? The slicks I used were brand shining new.
it's the measurement of the circumfernce of the tire. I had a pair of used slicks and the run out was 1.5" difference between the two and it put me towards the wall, scary stuff. Best way to measure is to wrap a string around the tire and measure the length (make sure both tires are equal psi), or lay a tape measure on the ground and start at the valve stem of the rim and slowly roll the wheel until you make one full revolution and do that with the other tire and see if they are close to the same measurement. Having one itre slightly taller will make it a scary ride.
Also you want to make sure the tires are fairly close to their manufacture date, my used ones were about 8 months made apart! I bought new ones and they are abouit 2 weeks apart, on the side wall, you'll see a 4 diget number, the first two represent the week and the last two represent the year they tire was made, example 3308=33rd week in 2008.
 

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Something else you might do: Make sure you are not lightly "jerking" the steering while shifting. When I was "new" to slicks & jamming gears hard; I was the one making the car unstable. With a little practice; my car became stable once more IMHO...:eek:
 

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Something else you might do: Make sure you are not lightly "jerking" the steering while shifting. When I was "new" to slicks & jamming gears hard; I was the one making the car unstable. With a little practice; my car became stable once more IMHO...:eek:
That's for sure, especially on a Russian street. Do what ever you need to do, Pingvvinov to go faster, just be careful.

OOps. this thread has just been blacked.
 

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I had the same problem at the track last Saturday in Fontana. I was running ET Streets (no tubes) at 12 psi when I powershifted into 4th gear I thought I was going to hit the wall but luckily I let out and didnt. This scarred the crap out of me. If anybody has resolved the same issue let me know. Thanks, Donavan
 

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you tend to get used to the "dog Tracking" with a soft sidewall. my first time was a puckering moment as well

add some air. a wider rim helps too
 
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