Topic: Tire pressures


sarahcecelia    -- 04-07-2018 @ 7:57 PM
  I have (2) 1950 Ford V8 sedans. One has "Coker- r 670/15 tires," the other has Firestone 670-15 tires with no "r " mark. Ray Marler, an old 1950 era Ford mechanic says the bias ply ones get what the sticker in the glove box says-21 lbs rear, and 24 lbs front. I was told the r means radial? does it? How can I tell a radial or a bias? What should either of these get for pressure? "Kubes". "Tom, anybody???"

Regards, Steve Lee

This message was edited by sarahcecelia on 4-9-18 @ 10:28 AM


TomO    -- 04-08-2018 @ 7:49 AM
  Steve, give Coker a call and ask them what pressure they would like you keep in your tires. Ford made its recommendation based on the tires available at the time and ride quality. Coker will probably give a recommendation based on traction and wear.

Tom


carcrazy    -- 04-08-2018 @ 8:18 AM
  Good advice from TomO. In our '53 with modern Goodyear radials we run 35 PSI in all tires.


42guy    -- 04-08-2018 @ 3:36 PM
  I have Diamondback and they say 35 psi.


len47merc    -- 04-08-2018 @ 5:11 PM
  Steve - from experience there is no relationship between radial and bias ply pressures. If you run 35 lb in bias plys you will wear out the center of the tread very quickly. With all due respect to Coker, they misadvised me to run 32 lbs in a set of Firestone 710-15s and the center of the tread was less than half of the edges in less than 3,000 miles. After extensive - and I mean very extensive - debate with them, they agreed with the universe of data I provided them and not only changed their recommendation for future sales of bias plys bit also replaced the full set of tires under warranty. I ran 26 lbs on the '47 Mercury for ~10K miles with the new set and the tread was still even on all 4. 26 lbs was printed on the glovebox sticker for Mercury btw.

Plus it rode like Flintstones versus Firestones at the higher pressure.

Recommend you run Ford's original recommendation for bias plys air pressure, and the tire manufacturers' recommendations for radials.

Steve

This message was edited by len47merc on 4-8-18 @ 5:12 PM


flathead4rd    -- 04-09-2018 @ 7:49 AM
  I always ran 28 lbs on bias tires 670.15 on my 50. When I switched over to radials I found it necessary to run about 34 lbs to avoid a wandering effect on the road.


sarahcecelia    -- 04-09-2018 @ 9:36 AM
  Thanks Tom. I knew you or "kubes" would come through for me!!!

Regards, Steve Lee

This message was edited by sarahcecelia on 4-9-18 @ 10:27 AM


sarahcecelia    -- 04-09-2018 @ 9:42 AM
  Tom, my big question is: How can I tell radials from bias???? And, would you run the same pressure(s) on all (4), or more in the fronts Ford says?????

Regards, Steve Lee


sarahcecelia    -- 04-09-2018 @ 10:26 AM
  Tom, I just phoned Coker and the guy said that radials have an R in the size between 670-15, like 670 R 1 5. He also said that mine are then bias,and to run 34 lbs. in all (4). How say you?


TomO    -- 04-10-2018 @ 7:30 AM
  Steve Lee, I am sorry, but it sounds like you got an empty barrel when you called Coker. I would never run 34lbs of pressure in the bias ply tires of a 1950 Ford. Like Steve Hansen said, you will wear out the center of the tire and have poor traction when trying to stop.

I like to keep my tires on the hard side to reduce heat build up. The owner's manual for my 40 Merc says 26Lbs all around and I keep 28Lbs all around. My Lincoln owners manual says 26 in the front and 22 in the rear, again I add 2lbs to each of them. These are all tube type tires, which tend to have a higher heat buildup than tubeless tires.

The tread pattern and size markings are different between radial and bias ply tires. Search for your size on Coker's website and you should be able to see the difference.

Tom


Yokomo99    -- 04-10-2018 @ 8:05 AM
  Radials and bias ply tires require different inflation pressures because they are made differently. A bias ply tire has a much stiffer sidewall than a radial tire. In a radial tire the cords run in parallel across the tire at a 90 degree angle to the bead. The cords on a bias ply cross at an angle to each other as they run cross the tire. The triangulation of the bias ply cords stiffens the tire carcass. That is why the radials require a higher inflation pressure, it is to compensate for the flexibility of the sidewall.

Matt

Be sure to check out my YouTube pages at:

https://www.youtube.com/user/MatthewBergin1

https://www.youtube.com/channel/UCJCdOfmXtM8xO9nXeQ-iSQQ


sarahcecelia    -- 04-10-2018 @ 12:52 PM
  34lbs. on all 4???

Regards, Steve Lee


sarahcecelia    -- 04-12-2018 @ 6:56 AM
  28 lbs on all 4 tires?? Ford calls for different pressures for front and rear.


sarahcecelia    -- 04-12-2018 @ 6:57 AM
  I think your right on that; but how can I get someone that really knows what they're talking about!!!??

Regards, Steve Lee


sarahcecelia    -- 04-13-2018 @ 6:02 AM
  Yours are radials, right??

Regards, Steve Lee


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