Tire pressure for radials

Tom's36coupe

Tom's36coupe

Well-known member
Just put the new Coker classic radial tires on and according to the sticker they say put 40lbs of air. Seems a little high even for a modern radial tire, they look fine but just wondering what others are using. The old Firestones had 25 lbs. Did not have my camera charged up yet, but will post some pictures later. What a difference in the way the car drives too!:)
 
follow the tire companys recomendation, i put #44 pounds in mine, it sure turns a lot easier, older cars with out power steering dont turn very easy with radials, thats why some tire companys making radials for the older cars have increased the recomended tire pressure
 
ford1 said:
follow the tire companys recomendation, i put #44 pounds in mine, it sure turns a lot easier, older cars with out power steering dont turn very easy with radials, thats why some tire companys making radials for the older cars have increased the recomended tire pressure
Click to expand...

Agreed. Some radial manufacturers are making high pressure radials today and if you don't keep the pressure up, they'll void your warrantee.
 
Mike, as a side note i have a 57 stude silver hawk with a set of the older radials on it said to inflate #32 max, at that pressure i couldnt park the car because it turned so hard, went to #44 and it drives and turns so much better
 
You might try using a little less psi in the front tires. This will help reduce the "pitching" these old rigs were born with.
 
I set the fronts at 38psi and the rears at 40psi, looks good and the ride is very smooth, much better than the old Firestones. I like the look of big rear and smaller front tire too, hot rod style but not too wild. The weather looks great for driving this weekend, should be fun!
 

Attachments

  • DSC04760.jpg
    DSC04760.jpg
    72.2 KB · Views: 31
  • DSC04765.jpg
    DSC04765.jpg
    59.6 KB · Views: 27
  • DSC04763.jpg
    DSC04763.jpg
    78.6 KB · Views: 28
If you're running them tubeless on old rims, I'd keep the pressure on the high side for safety's sake. If you're thrown into an emergency hard turn and the tire pressure is on the low side, it's possible that the side loading will pull the outside bead away from the rim causing a blow out. To prevent this, they started putting a small raised bead about a half inch inside of the outer rim flange to help hold the bead in place. A while ago, I asked if anyone had ever put a bead of weld on an old rim to duplicate this "safety" bead, but got no responses.
 
We used to run a very low pressure on race car tires,but we had what is called a "bead lock" to hold the Hooser tires on in turns.
 
Coker said run tubes, and that's what we did. Figured with my old rims it would be risky to not have them. I don't plan on running fast into the corners, just straight line!
 
Ok, I've put 2 x sets on Deuce roadsters recently and have 28psi front and 22psi rear. These are highboys, so quite light but now ride like the old 'normal' radials. We got there by chasing a decent contact pattern. At 40lbs they rode like solid wood and had about 1" of contact in the middle of the tread.

Put plenty of highway miles in the past few weeks and so far all is fine.
 
Changed the fronts to 36lbs this morning, kept the rears at 40. Still drives the same and looks good, its amazing how skinny the 550s look on the front, pretty cool! The 650s really fill the rear fenders, its going to take some time to get used to the look, kinda still miss my old Firestones.
 
Purists might not like what you've done, but I think you've made a good compromise for a stock looking car. You may miss the 'stones, but that's only because you're starting to forget the difference in ride and handling. :LOL:

Good call on the tubes btw, without the extra inner "bead" these old wheels aren't suitable for tubeless.
 
Besides "Merlot' we also run a 1954 MG TF. I have run radials for 16 years with tubes. I have had several flats, about 5, and every time it was a small piece of sand or grit or perhaps a small grain of rubber that wore a tiny hole in the tube, never a puncture in the tire. What I'm saying is "be scrupulously clean when assembling them"! Byron.
 
I have had some comments from the purists about my motor not being original. Was at one show and the guy asked me if it had a flathead, sure does I told him, then opened the hood and he told me that I ruined the car! I said if Henry Ford could of had aluminum heads, twin carbs and much better performance I think he would have been pretty happy! One of my critics is my 86 year old father, he does not really like the way the engine is hot rodded but he sure likes the way it drives and sounds! :cool:
 
Tire pressure is one of the most misunderstood subjects in the automotive industry.
The vehicle manufactures recommendations are generally always based on a nice comfortable ride, however,they generally add a statement about increasing the tire pressure for sustained highway speeds and loading.

Tire manufactures generally list the recommended press based on maximum loading. Since they have no control over what vehicle the tires are going to be used on, they tend to stay on the cautious side. Many tire manufactures also list the caution right on the side wall as to what size of wheel the tire must be mounted on.

Several years ago Ford and Firestone had a lot of trouble with tire failures that caused many fatalities... The problem turned out to be mainly Fords fault because they told Firestone how much they wanted to pay for the tires.. To meet the price demand by Ford, Firestone built tires that did not meet the DOT specifications. As the tires started failing, Ford compounded the problem by sending out letters to Ford owners telling them to lower the pressure of the tires. Low pressure causes tires to overheat, thereby causing the tire to fail.

I have been running radials on my vehicles since the early 1970's, the only problems I ever had with the radials were on tires that a tire dealer said I should use tubes in... Tubes in tubeless tires are a failure waiting to happen.

Most people run their radial tires under-inflated. that is why the shoulders are run off on the front tires.... Proper inflation has nothing to do with what the vehicle and/or tire manufactures say, proper inflation depends on the axle weight and the amount of contact the tire makes to the road. If the shoulders of the tires scrub off, the tire is under inflated... If the center of the tire shows wear, the tire is over inflated.

On my older cars I generally inflate the fronts to 34 psi and 32 psi on the rears. With the tire pressure over 30 lb's, there is very little likelihood that the tire will roll off the rim under normal driving conditions. Of course, the one variable is radial tires mounted on a rim that is to narrow for the tire and thereby pinches the sidewalls in.
 
I am a little surprised on how the tires look on my Ford rims. For the rears they fit really well, thought with the bigger 650 size they might look wide on the narrow wheels, 4". The fronts that are 550s actually have some extra rim showing. The old stones actually looked like they bulged out a little more than the radials do. Any possiblity that my ford rims are wider than 4"? Went for another drive today and still can't believe how much better the car drives.
 
Tom's36coupe said:
I am a little surprised on how the tires look on my Ford rims. For the rears they fit really well, thought with the bigger 650 size they might look wide on the narrow wheels, 4". The fronts that are 550s actually have some extra rim showing. The old stones actually looked like they bulged out a little more than the radials do. Any possiblity that my ford rims are wider than 4"? Went for another drive today and still can't believe how much better the car drives.
Click to expand...

If your '36 Ford has the original 36-39 wide bolt pattern wheels, then they are 4' rims. If you have the '40 and later 5 on 5.5 bolt pattern, you could have a rim that is anywhere from 5" to 6.5", the size depends on what year car and/or pickup truck they originally came from.
 
The wheels are the wide bolt pattern, so they must be 4". Coker and Diamond back differ on how you should run radials. Coker suggests running tubes and Diamond back says no way. What is the problem with having tubes?:confused:
 
Run the pressure as indicated on the tire, I have truck radials on the work van at 85 PSI, Your engine looks fantastic, most people who would moan about it are either ignorant or jealous. It's a shame that the average person who looks at a vintage car finds it his duty to insult the look of it and insult the owner of it, I wish these experts would concentrate more upon their own misgivings and short comings, perhaps a tighter nostril hair tailoring or a wax job to eliminate the unibrow they are sporting would occupy their day in a more positive way. Rule # 1, If you are going to insult a mans automobile I would suggest your woman be a looker and your own appearance be first rate, other wise, mosey. Again Tom, your stuff looks tops.
 
You must log in or register to reply here.
Back
Top