Tire contact patch pics??

[stroker1]

Anybody have a source I can go to and look at tire tracks and contact patch so I can help figure out whats going on with my buddies car? Tire tracks show the tires wadding up pretty bad with wobbles in the tracks from side to side. It's a 10.5" tire heavy car and we're trying to get it to hook with as much of the 1st stage as posswible and bring in the 2nd stage as quick as possible. So I'm looking to figure out what the tire tracks are telling me. I suspect the air pressure is low, but it IS NOT marking just on the outside. I have seen tires mark just on the outside edges when pressure was too low. But these are pretty even as far as amount of rubber left on the track. It shows the tires are wadding up bad, but we must hit tires hard with the heavy car in order to hook. He had the ladder bars running more down hill towards the front, but it would not hook for nothing. When we raised the front of the ladder bars it helped tremendously. They are close to being level right now. We also stiffened up the rear shocks and loosened the extension of the front shocks. But now they are wadding up. Maybe that's just the nature of the beast, but problem is it still breaks traction about 60ft out, right about the time the 2nd stage is set to come in. When we bring the 2nd stage in .5 sec later it hooked OK. We where just trying to maximize the car and get more numbers out of it. There is power galore in the 565BBC but we are having a hard time getting it to the ground. It's a '71 Z28 with ladder bars. The 1st shot is a fogger with a progressive. Then the 2nd stage is a plate set to come in at 1.3 seconds. If we go to 1.8 sec. on the 2nd stage it will take it, but barely.

If anybody has any detailed pics of tire patch tracks I'd love to see them. Thanks!!
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[John_Heard]

I dug around and found an older discussion we were having a while back about this, perhaps this will give you some ideas

viewtopic.php?f=1&t=2596

[stroker1]

John, thanks so much for the response. That is just what I was looking for. We went to Fayetteville today and had the same trouble. After some heated discussion, tried some different things. Leaving lower on the transbrake and more air pressure in the tires. Finally the car left hard and straight. Everyone was happy, including me. I was starting to be the squeaky wheel that everybody didn't want to hear. After I saw your link, I remember looking at it last year or sometime back. It had stuck in my memory and it was just what I was looking for.

I think we are now somewhere between the old condition of blowing the tires off with no weight transfer and the condition we where just seeing of hitting the tires too hard for the amount of air we had in them. Still hitting them pretty hard, but not squashing them as far down and letting them wad up.

[John_Heard]

Good deal, glad to hear you guys got it figured out!

[novaz]

theres A couple pages in Daves Dorslammer book
169/170/171
thats been helpful to me and also on his video he talks about wear characteristics
Good Luck