Bigger tires - Higher PSI ???

  #1  
Old 04-02-2008, 11:41 AM
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Default Bigger tires - Higher PSI ???

I took my stock 265-65-18s off and replaced them with 285-65-18s. Do I run the same psi, 35, or more, say 40? I've
read past threads, and they give conflicting advice.
How about some help!
 
  #2  
Old 04-02-2008, 11:46 AM
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Default RE: Bigger tires - Higher PSI ???

Oh boy, here we go again. (This has been a debate before) I would say run 35 like before. As long as the tires wear even you are ok.
 
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Old 04-03-2008, 10:11 PM
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Default RE: Bigger tires - Higher PSI ???

I'd dis-agree with running the same. However you won't need a dramatic change in tire pressure. You increased the width of the tire by 20 mm, therefore increaseing the sidewall(the key factor in psi) even though it's the same series(65) it's not the same height, I don't feel like doing the math as I can't find my calculator and i hate the one on the computer. But to figure the air pressure you should run, figure out what increase you made percentage wise. What % is 20mm from 265=%of tire size increase. I think that's like 7.5. Then Increase your tire pressure that same amount. 35x7.5 I'd estimate around 37-38 psi. Actually I gave in and used the calculator on my computer if it were me I would run at 37.7psi or 38 if you don't have a good digital gauge.
 
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Old 04-03-2008, 10:16 PM
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Default RE: Bigger tires - Higher PSI ???

Dose it say what to run on the side of the tire thats what I always go by.
 
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Old 04-03-2008, 10:26 PM
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Default RE: Bigger tires - Higher PSI ???


ORIGINAL: rxsteven

Dose it say what to run on the side of the tire thats what I always go by.
That is usually just Cold MAX because besides sidewall heigth the other factor is the weight of the vehicle. Filling them to that doesn't really hurt anything, unless you have alloy wheels and then they won't seal very well at all, and you will constantly be airing up on a regular basis.
 
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Old 04-03-2008, 10:26 PM
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Default RE: Bigger tires - Higher PSI ???

I don't want to start anything but it all comes down to what kind of ride your looking for man. Again JUST MY .02 CENTS WORTH, but in my OPINION there is no such thing as a perfect tire pressure. It all depends on so many different factors that you just have to run several different tire pressures and see how you like it. On top of that. Every tire pressure gauge is a tiny bit different than another one unless you get into a GOOD quality gauge. Which means you don't know if the pressure you put in there is "exact". Ultimately your gonna wanna stay close to the factory air pressure decal on the door in order for the tire to wear out correctly. If you run too much pressure, you stiffen the ride and you wear out the center of the tire more than the outside edges of the tire. If you run too little you soften the ride and you wear out the outside edges of the tire more than the center of the tire. You have to find the happy medium of wear you want it set(quality of the ride wise) and deside how far away you wanna go from the factory setting and then justify wearing the tires out incorrectly. Honestly, I rarely check my tire pressures but I keep them at 35psi front and rear and they are a bit bigger than the factory tire size rating. But I've had them for a year and so far they are wearing out perfectly even. Good luck. Don't forget to use the FAQ on the top of the Silverado page if you have any more questions.
 
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Old 04-03-2008, 10:28 PM
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Default RE: Bigger tires - Higher PSI ???

ORIGINAL: rxsteven

Dose it say what to run on the side of the tire thats what I always go by.
Rollingthunder is right. That is the MAX pressure and definately not wear you want it set at. That will equal out to a stiff ride and wear out the center of the tire a lot more than the rest of the tire as opposed to wearing it out evenly.
 
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Old 04-03-2008, 10:29 PM
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Default RE: Bigger tires - Higher PSI ???

This is gonna get moved to FAQ soon to fill the void. That way we can quit hashing this, LOL!
 
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Old 04-04-2008, 07:31 AM
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Default RE: Bigger tires - Higher PSI ???

Look on the tire for the psi, whatever it says (say 65, subtract 5 to 10) if you are running mostly on pavement and want to get better mpg. If you are offroading and want a comfier ride, then lower the psi like 15-20 psi from whatever it says on your tire.
 
  #10  
Old 04-04-2008, 07:44 AM
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Default RE: Bigger tires - Higher PSI ???

Dude where did you get that? Read the other posts. This is one subject where I definately know what I'm talking about.
 

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