Coker radial air pressure for 19" tires

[old31]

What are you guys running for air pressure on Coker radials. I have been running 35 psi for the last few years.

I have been hearing anything from 35-48psi.

I am pretty sure the 35 number comes from the original biased psi ratings. But that does not mean they are the best for today's higher speed driving with radials.

Inquiring minds want to know.

[ndnchf]

Have you asked Coker? They should be able to provide a recommendation for their tires.

[Rob Doe]

In general aviation, proper tire pressure is based on gross weight of the aircraft. I speculate that 48lbs tire pressure on a Model A would mean that you have 4 Japanese sumo wrestlers and their luggage on board. LOL

[CarlG]

My Coker radials have molded into the sidewall "44psi MAX" I run them at 40.

[denniskliesen]

Depends on the brand of tire. Coker sells 2 different brand radials. Mine have the max pressure molded on the sidewall.

[Jim M]

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I run regular tires (no radials) at 35 PSI. Works great!

[nkaminar]

Modern tires will take up to 200 psi before exploding if they are not damaged, for instance by running them flat. I run 50 psi in the rear and 45 in the front for my heavy 1930 Fordor. The tires should be warm after a drive and not hot. More damage is caused by running them with low air pressure than high air pressure. The 35 psi was for the bias ply tires.

[old31]

Originally Posted by ndnchf

Have you asked Coker? They should be able to provide a recommendation for their tires.

I did, and the rep said, well I am not sure, it should be on the sidewall.

[Boston Bruce]

Originally Posted by CarlG

My Coker radials have molded into the sidewall "44psi MAX" I run them at 40.

I run mine at 40psi also. The ride felt a little "greasy" at 35psi.

[1931 flamingo]

At 35 psi are you having a problem, tire wear, squealing, bouncing, anything??

If not broken why try to fix it??
Paul in CT

[nkaminar]

At 35 psi the tires defect too much and run hot which can destroy the tubes. Plus they run "greasy" as Bruce said. That means that the tread defects too much from the direction that the wheels are pointed. And I think that the mileage would suffer. The trick is to put enough air in so that they run warm and defect like radial should but no too much.

The radials are great tires. The hold the road better and ride better and should last longer than the bias ply tires.

[old31]

1931, I am not having any problems. I just want to see if something is better than the 35psi I have been using.

My guess is that 35 would ride softer than 40psi?

[katy]

Try 40 PSI and report back.

[loubob]

I ran 38psi on my '30 coupe and it was like driving the car with power steering.
The ride was excellent!

[old31]

Update:

Well, I went from 35psi to 40 psi and i could not tell any difference. Drove on the highways and the backroads, smooth and bumpy with cracks.

[J Franklin]

Originally Posted by old31

Update:

Well, I went from 35psi to 40 psi and i could not tell any difference. Drove on the highways and the backroads, smooth and bumpy with cracks.

Then it would be best to keep them at 40.

[Synchro909]

Originally Posted by nkaminar

At 35 psi the tires defect too much and run hot which can destroy the tubes. Plus they run "greasy" as Bruce said. That means that the tread defects too much from the direction that the wheels are pointed. And I think that the mileage would suffer. The trick is to put enough air in so that they run warm and defect like radial should but no too much.

The radials are great tires. The hold the road better and ride better and should last longer than the bias ply tires.

It would be a good thing if they did last longer. That would help compensate for the higher price but I'm not sure they do after speaking with others who have used them.
Is there a consensus out there on the life of a radial tyre vs cross ply?

[nkaminar]

Synchro, If you do a Google search for radial tires vs. bias ply tires you will find that all results say that the radials will last longer. Here are a couple of hits from my search:

https://en.wikipedia.org/wiki/Radial_tire

https://web.archive.org/web/20071207...Two-Tires.html

The results say that the radial tires will last longer and provide a little better gas mileage. However, they must be inflated properly. The test to see if they are inflated properly is to put you hand on the sidewall after a fairly long drive. If the tires are warm then you are good. If they feel hot then they need more air. In general the radial tires will run cooler than bias ply tires.

The research also says that the bias ply tires will hold more weight than the radials. So if you are hauling coal in your AA dump truck, then use the bias ply tires.

[Synchro909]

Originally Posted by nkaminar

Synchro, If you do a Google search for radial tires vs. bias ply tires you will find that all results say that the radials will last longer. Here are a couple of hits from my search:

https://en.wikipedia.org/wiki/Radial_tire

https://web.archive.org/web/20071207...Two-Tires.html

The results say that the radial tires will last longer and provide a little better gas mileage. However, they must be inflated properly. The test to see if they are inflated properly is to put you hand on the sidewall after a fairly long drive. If the tires are warm then you are good. If they feel hot then they need more air. In general the radial tires will run cooler than bias ply tires.

The research also says that the bias ply tires will hold more weight than the radials. So if you are hauling coal in your AA dump truck, then use the bias ply tires.

Over here, the authorities can be pretty deadly on overloading tyres etc when towing and considering the weight on the back of the car when I'm towing, it looks like I stick with bias ply tyres with a 6 ply rating. I've been running 5.02X21 Firestone tyres and lately, 8 ply light truck 16" radial tyres. Both have been OK but it's time for new rubber for both towing and solo car use.

[Rckjone]

I run mine at 40psi also