yet another tire pressure thread (up 1 size from stock tires)

[JBV]

can the world handle any more pixels spilled about tire pressure? how many threads on how many forums? does the internet have the capacity?

my new Ram has the Falken wildpeaks in 18 x 275 r 65. stock placard pressures on my crew cab 6 4 box, 38/38.
just had new tires installed on stock rims, 275 x 70 r 18. slightly larger. Sumitomo Encounter AT load range e/10 ply rating.

i understand this is a complicated and loaded question. the tire shop guys don't take any chances 'go with the placard', it's there for a reason. i get it. for unloaded, not towing, regular on road driving, i do wonder if the pressure should remain the same or go up/down a few psi. should i contract the tire wizard to do the maths? weigh the front and back of the truck and do the maths?

if you've got any insights, method, or otherwise tire voodoo stories, i'm all ears.

 

[Buz]

Since you went up in size, you probably need to LOWER your psi a few lbs.
But go here to confirm: https://tiresize.com/pressure-calculator/

 

[Scram1500]

I went lower after going up a size,

 

[ferraiolo1]

It’s based on the ply and rating, not the tire size in a lot of cases.

I had best luck with 43f and 40r with my 10ply tires. Too little of pressure and the truck will feel squirmy and cause odd wear patterns.


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[JBV]

thanks guys. yes, lower does seem to be the case as i discovered, according to the calculators. the weight diff front to back is about 60/40 from going to the dump and having the truck weighed on the scales. drive forward, drive backwards, etc. the lady was very accommodating of my funny request. i wonder if i should put 2 psi more in the front? i'll do a chalk test but that won't happen until it's dry again, which won't be until next spring.

 

[ferraiolo1]

Did any of those calculators factor in ply/rating change over Oem?

Try 43/40. It’s what I run in my E rated tires after doing the chalk test.


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[JBV]

that would make some sense. i imagine there is differences from truck to truck as well. mine is crew cab 6 4 box, ORG on 18's. the new tires are up one rating to E from D.