Thread: 1932 5 window highboy tire size

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Originally Posted by John Palmer

Not exactly the same front wheel size, but here's what I've been running for the last 7,000 miles on my High Boy.

Fronts are 15x7 Torque Thrust 2's with P195/60R15 (23" tall) BF Goodrich T/A tires. 15x10 rears with P285/70R15 (30" tall) T/A tires. They work fine, but I run the tire pressures very low and the tires squeal a little "only during braking" when you go over painted STOP lines. They show no wear pattern at all so far.

I run exactly the same as John, same wheels, same tires. I run 25 lbs in the front tires and 20 lbs in the rear tires. Works for me.

Dumb question, but what's the idea of running such low air pressures? Better ride? On a 15x10" wheel, is there alot of sidewall "buldge" with the 285-70 15 tires? Mine has that size on the rear, but I'm not sure if my wheels are 8" or 10"... I'm thinking mine are only 8"s.

These cars are so light that lower air pressure is necessary to make the tires sit right on the road surface. Otherwise, your tires will be too rounded and only the centers will make contact with the road. It also affects ride as higher pressures will give you a harsh ride.

Originally Posted by rumrumm

These cars are so light that lower air pressure is necessary to make the tires sit right on the road surface. Otherwise, your tires will be too rounded and only the centers will make contact with the road. It also affects ride as higher pressures will give you a harsh ride.

Thats what i figured the theory was... is it safe to run for prolonged intervals at 75 mph on tires with only 20 lbs of air in them?

From what i've been able to measure with the wheels on the car, and the tires mounted, I think I have 8" wide wheels rather than 10's... as you can see there is considerable "buldge" in the sidewall, and the tread of the tire seems to actually be wider than the rim itself... Personally, I think the 285's look a little too big on the back of a highboy, and am thinking of going with some much skinnier bias-ply whites on the front and back both... I haven't really got a chance to drive the car at all yet, so i want to get some "experience" with the radials for awhile, as I heard the bias plys can be a bit squirrely compared to radials, although I do have bias plys on both my 69 Camaro and 70 Nova with no real drivability problems on either.