Tubeless tire pressure
 

I recently changed to tubeless slicks,Hoosier 29 x 9 (bias ply).The car is an automatic weighing 3300 pounds.I am still running 12.75 pounds of air.But after looking at this picture I think I need to raise the pressure.Any suggestions of where the pressure should be?

Re: Tubeless tire pressure
 

What size is the rim? J.R.

Re: Tubeless tire pressure
 

I've heard pressures from 14 to 25+ lbs from 9" tire racers. Lot's of variables, but most seem to be in the high teen to low 20 range. I have Hoosier 9"X 30" Lightweight Radial Slicks at 21 lbs on a 10" rim, car weighing 3,540 and footbraking. Wider rims allow more pressure and radials seem to like a little more than bias ply. I fine-tuned it by watching if contact is being made all the way across the tread (may need less if not) or if rubber is being laid over the side (may need more).

Re: Tubeless tire pressure
 

They are 15 x 10 rims. The car is working great ,but I'm concerned about how safe it is.Thinking of going up 1/2 to 3/4 of a pound and see what happens.

Re: Tubeless tire pressure
 

Try 20 PSI. Don't be afraid of more pressure in the radials.

Re: Tubeless tire pressure
 

I run 15x10 with 29.5x9 bias ply but a stick car. Never been above 15 lbs unless I want to spin. OP stated bias ply. Try 13 lbs and work up from there.

Sean

Re: Tubeless tire pressure
 

Bias ply and radials have nothing in common. Start at 20 lbs. with a 10
inch rim, and go UP from there.

Re: Tubeless tire pressure
 

Same tire and wheel size on one of our bracket cars = 16 to 17 is where we
ended up. Seemed high for bias but lower pressure really tore up sidewall.
Our car is 3300 LB. with 1.5 to 60 Ft.

Re: Tubeless tire pressure
 

What does the car usually 60' like? Definitely more pressure, the tire looks like it's trying to roll over itself.


I would up the pressure a bit, work towards 13-14lbs., and maybe make a shock adjustment if needed also.


I'm no expert though.

Re: Tubeless tire pressure
 

Usually low to mid 1.60's. I will have to up the pressure and mess with the rear shocks.I see a day of testing in my future. Thanks

Re: Tubeless tire pressure
 

Mike,

I run 29.5x9 bias or 28x10 bias on my 67 Firebird when bracket racing. Also run radials at times, but summer heat in TX, I trust the bias more.

I weigh 3350 and 60' 1.48-1.52 depending on track and launch rpm... I normally run about 14 psi in the bias tires. Normally on 10" rim. 20 psi in the radials. Auto with 5200 rpm converter. Footbrake. GM ZZ4 legal crate motor.

Hope this helps. Good luck.

Ken

Stock 412

Re: Tubeless tire pressure
 

I used to run 14 PSI or less in my 10.5 bias ply slicks. Now I run 20 pounds, I found that the higher I go the more reliably it hooks.

I don't doubt it would be okay with more pressure but it's been so long since they've spun that I stopped experimenting.