NSS Tire Shake Problem

[Dads426]

We are running Hoosier Bias 29.5x10.5-15 D06 and when the tires are new (basically 1/2 a season old; we run about 9-10 races a year) we don't have any issues. But as the tires age, we are experiencing tire shake 10-20 feet out up to the 60' clock (usually during the wheelstand). Pressure is 12-14 lbs (changing it didn't help). Tried different shock settings. We have rotated the tires. Car is a 64 Dodge Polara running NSS, 493 wedge making about 650-700 HP, Auto with 2.77 first gear, 4.10 Dana. Typical ETs are 9.95 to 10.10 at 135 mph. When it doesn't shake, 60' times are in the 1.35 range; when it shakes, it drops to 1.46. It is not wheel hop and is not noticeable when viewing outside the car, but the driver can feel it (shakes the tach& dash pretty bad). Car weighs 3500 w/driver. Hoosier says the sidewalls are not designed for a 3500 lb car and we can't go any wider. They suggested lowering the pressure so the tire cups at launch and spins (from less contact area) since the tire is biting hard and rolling over on itself. Anyone experience this problem and what did you do (besides buying new tires mid season)?


Thanks.

[Bob Pagano]

Tubes or tubeless ? If tubes get rid of them, get a lite wheel and lose the screws you dont need them. If I were still running a max wedge that is what I would do just by looking at the picture. good luck. bp

[Dads426]

Originally Posted by Bob Pagano

Tubes or tubeless ? If tubes get rid of them, get a lite wheel and lose the screws you dont need them. If I were still running a max wedge that is what I would do just by looking at the picture. good luck. bp

We do run tubes. I'll talk to Hoosier about running tubeless. I've been thinking about lighter wheels, but I like the stock rim look (don't mind the fronts...) I wish someone would make a stock looking rim in aluminum.

[John Dinkel]

How wide are the wheels?

[Ed Wright]

Those tires like 12" wheels. I used to run them.

[treessavoy]

As someone who used to run in NSS I understand about wanting to keep the original look. If you have to buy wheels look for some SuperTricks on ebay or another site, they are pretty much period correct and offer weight loss, some guys even painted them the color of the car.

JimR

[Dads426]

Wheels are 10" wide, but due to the stock width Dana have a custom offset. Been thinking about lighter wheels, but finding the correct offset may be challenging.

BTW, why would not running tubes help? What amount of air pressure do you run? Is 12-14 psi in the ballpark?

[Ed Wright]

Originally Posted by Dads426

Wheels are 10" wide, but due to the stock width Dana have a custom offset. Been thinking about lighter wheels, but finding the correct offset may be challenging.

BTW, why would not running tubes help? What amount of air pressure do you run? Is 12-14 psi in the ballpark?

I used 16 to 18 psi with 12" wheels.

[Bob Pagano]

BTW, why would not running tubes help?

As the sidewalls start to breakin the tire wads up, then the tube wads up inside causing an imbalance = tire shake

[Dan Walcott]

Originally Posted by Dads426

Wheels are 10" wide, but due to the stock width Dana have a custom offset. Been thinking about lighter wheels, but finding the correct offset may be challenging.

BTW, why would not running tubes help? What amount of air pressure do you run? Is 12-14 psi in the ballpark?

What is the back the custom back spacing now?

Get rid of the tubes and save your money buying natural rubber racing tubes.

Keep adding air till the "hook" slows. You will be surprized how much you end up with.