Tire pressure-50' Crestliner

[Bob from Northport]

Can anyone recommend tire pressures for a 50' Ford Crestliner running 6:70x15 B>F> Goodrich Silvertown bias tires???

[jayvee34]

I have always run 32psi., front and rear in all my bias ply tires.

[tubman]

I believe the sticker on the inside of the glove box door in my '51 club coupe as well as the owners manual calls for 28 psi front and 24 psi rear for 6.70X15 tires. I may be wrong on the exact numbers, but do remember very well that I was surprised at how low it was. Something to remember is that car manufacturers quote tire pressures that produce the best ride, while tire manufacturers quote pressures the produce the longest tire wear. Given the fact that tire manufacturing techniques and materials may have changed since 1950, I believe that using the tire manufacturer's recommended pressure shown on the sidewall of the tire is the best way to go.

[rustythumb]

i think the pressure on the sidewall is the maximum pressure, not the recommended p.s.i. for any particular car. is this wrong?

[tubman]

You are correct. As I stated in my previous post, tire manufacturers rate the pressure for the longest wear. If you feel the need to drop it some to improve the ride, it's up to you. Perhaps 1/2 way between the tire manufacturers and automobile manufacturers recommendations may be best?

[Flathead Fever]

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Another marathon answers. If you were to put 32 psi in your Crestliner with factory size tires and the sticker said 28 front and 24 rear its going to ride hard, your going to feel every bump. It will made a big difference in ride qulaity lowering the pressure to the factory recommendations

I have literally installed thousands of tires and monitored each one through their wear life. When I retired, I bought my own used machine and balancer because wasn't paying for something I had done my whole life. At the phone company we had mechanics that wanted to air the tires to the maximum pressure stated on the sidewalls and others that went by the sticker on the vehicle door jambs. When the Ford Explorers with the factory installed Firestone 321 tires that were coming apart were causing rollovers and killing people, for liability reasons phone company management sent out a memo stating that we were only to fill the tires to the amount stated on the door jamb sticker. We were running different types of Firestone tires at the time, and they were all terrible tires. We had a national account which meant we could buy tires cheaper than the local Firestone dealer could. Almost all of them separated before they wore out. We had some of those 321 tires on small cars and the joke in the shop was it was three cords wrapped around two more cords wrapped around a bomb. I literally never saw one wear out before it separated. For years we had used BF Goodrich tires without a problem and then for cost reasons they went to the Firestones. Had they factored in the tow truck costs, the drivers down time and the time the mechanics spent changing tires it was costing them more money. Not to mention the safety problem. To this day I cannot buy Firestone for my daily drivers. I do buy them for my collector cars.

The aerial boom trucks inn the fleet had a tire sticker attached by the aerial boom manufacturer that was different than the truck manufacturer, because the trucks were at their maximum gross vehicle weight with the utility body and aerial boom. The rear tire pressures were usually the maximum of the tires. Once a year fleet management would perform garage inspections. Part of the inspections was to randomly select several vehicles out of the fleet and check the air pressures to make sure we were going by the stickers. That ended the debate between the mechanics as to what pressure was the best to use. We only went by the sticker.

Always start out by what the sticker recommends but because every brand will wear differently, and because people install different size tires than the factory used, or they carry different weights, or they drive winding mountain roads and dirt roads the sticker pressure might not be the best choice. Start with that sticker pressure and watch the tires to see how they wear. If they are wearing the center tread down, take out a few pounds of air and if they are wearing both outside treads down add a few pounds wiht out going over the maximum rating. I knew guy that was so anal about it he put chalk on the garage floor and then rolled his cars a crossed it to see the tire tread contact pattern and then he adjusted the air pressure. Some people are after the best fuel mileage, so they air the tires to the maximum. That is fine if you take into account the cost of the tires when they wear out the center tread. Some people like a softer ride and they take out a few pounds from what the manufacturer suggests. In the 1960s and 1970s everybody I knew ran 32 psi in their bias ply tires. Everybody that drove a car knew that tire pressure number. Today, my cars just sit in the garage, every once in a while, I go through my collection and air everything to 32 psi. The tires will rot off my cars long before they ever wear out.

[sidevalve8ba]

And if you air them up to the maximum the car generally rides like a buckboard!

[cadillac512]

Originally Posted by rustythumb

i think the pressure on the sidewall is the maximum pressure, not the recommended p.s.i. for any particular car. is this wrong?

Absolutely correct. The number on the tire clearly states the max load capacity at maximum pressure which has nothing to do with the car manufacturers specs. If you want the car to ride like it should, follow the car manufacturers specs, not the sidewall of the tires.

Now, there are a few exceptions like changing sizes or bias to radial, but the inflation pressure will still be far below max as shown on the tires.


Terry

[cas3]

it seems 28-32 was the norm before the radials took over I think.

[RalphG]

Looking in the 1953 Ford manual I see pressure recommendations quite low with 24 to 26 on the front and 23 to 26 rear depending on whether its 6.70 or 7.10x15 four ply. 53 Mercury manual recommends 26 psi front and 23 rear. I run steel belted radials on my 52 and try to keep around the 28 to 30 psi setting. Fine on smooth pavement but it rides hard on rough roads at that pressure.

[Shoebox on Whidbey]

I have a 1950 Custom Convertible with radials. What tire pressure is recommended since changed from bias ply to radials?

[tubman]

The problem is that there are usually two recommended tires pressures. The tire manufacturer specifies one that provides maximum tire life (it's on the sidewall). Automobile manufactures specify a pressure that provides maximum ride comfort. (It's usually on a sticker in the door jamb.) They are often different. Find a car of similar weight and tire size and see what they recommend.

That's a lot of work. Start with the spec on the sidewall and drop a few psi if it seems to ride too harsh.

[34fordy]

I believe a radial tire which has a more flexible sidewall will give a more comfortable ride than a bias ply tire with an identical pressure. I do not think longevity in mileage is much of a consideration for most of our cars. Most will be beyond the safe tire age before they are worn enough for replacement.
Run them at the pressure that handles well and rides to your own particular satisfaction. IMHO.

[Dick]

Photo of the glove box decal on my '49 club coupe.

I put radials on it and run them at 32 psi.

The radials were a huge improvement!

[flatford8]

Isn’t the recommended pressure on tire sidewall for maximum load. Passengers, luggage,fuel. A fully loaded vehicle. If your not running at maximum load you wouldn’t want the max pressure. It doesn’t matter whether they’re radial or bias.....Mark

[petehoovie]

Originally Posted by Dick

Photo of the glove box decal on my '49 club coupe.

I put radials on it and run them at 32 psi.

The radials were a huge improvement!