Well........that was interesting

[justinp61]

I have a 6.50ish race coming up in a couple weeks at my local track. The track is not really a decent radial track, so my plan is to run slicks for the race.

Last night they had a small tire no prep race and grudge racing, $20 for the grudge, as many passes as you want. I already had the slicks on, so I loaded up to make a few hits. The combo that's in the car now has never been on a slick so I needed to do some testing and find some shock settings. The plan was to make some 330' hits to get a good base line and come home.

On the first pass I took a WAG on the shock settings and 14 psi on the slicks, it spun bad and drove left when it hooked, so I coasted through. After changing the shock settings and making an adjustment to the cal trac bars I lowered the tire pressure to 13 1/2 lbs. It hooked and went straight, 1.40 60', but man did it move around, coasted through, 6.86 @ 77 mph. For the third apss the only change was an added 1/2 lb of air pressure to the slicks, it hooked again, 1.44 60', coasting through again, 6.77 @ 82, it still moved around a lot. The last pass the only change was using the trans brake, the car spun then hooked, despite the moving around I ran it out, 6.37 @ 108 with a 1.45 60'.

After having been on radials for several years the slicks were a bit unnerving, I felt like the dog being wagged by the tail. lol

 

[rmchrgr]

Nice job getting it to stick. Any idea why it's moving around so much? Maybe you need ballast?

 

['68cuda416]

That's just the inherit nature of slicks is that they give you an uneasy feeling on the top end to differing degrees, that is why the radial classes are so popular now as they are way more stable feeling at speed with the increased sidewall and ultimately faster than a slick. The main advantage of a slick over a drag radial in my opinion is the fact that a slick can recover from a slip of the tire and infact a controlled spin is actually wanted to obtain wheel speed for a slick to be fast whereas a drag radial does not recover well if you knock the tire off.

 

[justinp61]

That's just the inherit nature of slicks is that they give you an uneasy feeling on the top end to differing degrees, that is why the radial classes are so popular now as they are way more stable feeling at speed with the increased sidewall and ultimately faster than a slick. The main advantage of a slick over a drag radial in my opinion is the fact that a slick can recover from a slip of the tire and infact a controlled spin is actually wanted to obtain wheel speed for a slick to be fast whereas a drag radial does not recover well if you knock the tire off.

^^This^^

If the trans brake hit had been on radials, it wouldn't've recovered.

 

[rmchrgr]

OK, two more questions - do you have tubes? Radial fronts or bias?

I've had radials since 2012 and have not run my car with slicks. I'm just curious about what you're describing.

 

[67Dart273]

Slicks wobble around back there like you got two half flat tires--which you do

 

[justinp61]

OK, two more questions - do you have tubes? Radial fronts or bias?

I've had radials since 2012 and have not run my car with slicks. I'm just curious about what you're describing.

No tubes, yes, radial on the front. I've mixed them on the street and never had any issues. It's just the nature of a slick.

 

[B3422w5]

No tubes, yes, radial on the front. I've mixed them on the street and never had any issues. It's just the nature of a slick.

guy above made a good point.
running tubes in those tires will definitely stiffen up the tire and make it less Wobbly.
I ran QTP’s on my W5 deal, initially without, on an 8 inch wheel, creepy on the big end on a 9 sec pass with super stock springs.
went to 10 inch wheel, nice improvement regards stability.
then went to tubes, another notable improvement/ difference.
Sidewalls good bit stiffer. I was on a 28 by 11.5( 28 by 10 measured) basically they are a bias slick

 

[Inertia]

They are called "wrinkle" wall slicks for a reason . lol