I'd appreciate advice on what tire pressure works well running 750x16 Firestone bias-plies on the back of a steel 32 sedan. Switching from radials I've started low at the back but it wallows at speed and I reckon I need to go firmer - what works for you? thanks Simon
Back when radials were coming on line, the "inflation profile" of the radial often appeared to be slightly lower than the bias ply tire. One technique I learned at a road course track, was to put chalk marks on the side wall of the tire, and then run around the course, to see just how far up the side you wore the chalk off. My sense still is, that you are seeking a compromise of low rolling resistance (higher pressure) with optimal traction (lower pressure). The flexing of the sidewall is the hysteresis loss that results in heating up the tire. "Mileage may suffer" they say. You definitely do want to have enough footprint, so that there's static friction (no skidding) when you hit the brakes and the rears are about to lock up.
I don't remember, but when I got mine I thought they had a sticker saying 35 lbs recommended tire pressure!
I was going to go with what Pitman basically said. I was always taught to properly check your tire pressure based upon your specific vehicle setup was to take chalk and mark a line across the tread. Then drive forward and back a bit and recheck. Your proper pressure will be achieved whenever you are scrubbing the chalk off of the entire tread width and not just the centers or the edges of the tire. Of course, I was raised with radials and am only ***uming this is the same with bias ply and tubes.
i have 700's not 7.50's....but on my roadster im running 22lbs in the rear i had them at 32 when i got the car done and it was like a buckboard....now its pretty good id think with the extra weight of the sedan...the 25#'s royal shifter mentioned would be good Zach
Some of the 70s & 80s T-buckets would run as little as 16 psi in the rear tires, as they were a wee-bit oversized for the application.
Thanks for the replies so far. When I ran tall fat radials I was able to drop to 20psi for a nice ride and good grip, but this seems too low for the bias ply. I'll try 25 and the chalk idea Any other experiences from tall bias-plies on steel cars? thanks
Wife's 33-5W has 5.60-15 and 8.20-15 and they've got 28 psi in them and she hasn't complained. Back in the 60's I can remember running 24 to 26 psi in the 13 and 14 inch bias-ply tires at that time. swifrty
I don't think ANY tires have a RECOMMENDED tire pressure on them. They have a MAXIMUM pressure listed on them! Look at your tires.
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