Christophe2m6

Hi guys!!

I have a 1969 Cutlass Supreme (V8 350), holiday coupe, auto trans with modern 205/75 14''.
Need to check tire pressure and wondering what would be the correct tire pressure with modern radial tires.

I found on the site that with old ply tires, it should be about 26psi, but what about new radial tires?

Thanks a lot for all your help!

Fun71

I run my BF Goodrich 245-60-15s at 30 to 35 psi. Those old tire pressure recommendations were to assure a comfortable ride.

1970cs

I run 32-33 PSI in my P225-70-14" BFG's

Pat

oldsmobiledave

35 psi up front & 30 psi out back. Chalk your tires across the tread then roll the car forward & see what is left of your chalk mark. Once the chalk mark is gone across the entire width of the tire tread then you have the right psi. If you only wear off the chalk on the middle of the tire you have too much pressure.


Class is over.

oldcutlass

Most older bias ply tires were set at around 28. For newer tires, each manufacturer is different I run 30#'s in my BFG's. It really depends on the max pressure rating per the weight capacity of the tire.

joe_padavano

I'll echo the 32-35 psi range, but I have to admit that Dave's tutorial with the chalk mark test is pretty cool.

oldcutlass

The chalk mark test may be ok for matched tires and wheels. May not be good for a tire that is at the extreme ends in width vs minimum or max width wheels.

steverw

Im a 32 psi guy

Christophe2m6

Thanks a lot for your help!!!
Run now with 32psi, cars drives great!

35tac

I reset my cold tire pressure of 34 all around to 30 on the rear and 32 on the front. With a 30 minute run today and the outside temp of 60 degrees the end result was 32 on the rear and 34 on the front. Tried the chalk at the same time and removed the chalk evenly across the 4 wheels. Chalk was about 2 inches wide and was removed totally across all 4 wheels. The ride felt nice. Hum is still there and I am sure rims may change the result. Thanks for the help.
Wayne

oldsmobiledave

I leárned that chalk technique from an older enthusiast about 30 years ago. It just flat out works and I share it when asked about air pressure. Feel free to pass it along to others.

alain

The chalk mark technic works for me too
Alain