Aftermarket tire psi

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duckman631

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The tire pressure rating listed on the doorframe says tires should be 39 max psi.

If you get aftermarket tires like falken wildpeaks and the psi for the tire is listed at max 50, do you air them up to the max or stick with max 39 per the trucks specs.

Thanks!
 

pacofortacos

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Run at the 39-40 normally, if you increase your load then you can air up.
Usually the higher psi tires have a higher load capacity - which you can verify on the sidewall if they do or not as long as you know your old tire's load capacity.
If that is the case, then you have to air up to take advantage of the extra load carrying abilities.

Or

You can do a more accurate test and perform the chalk test and set your psi for your tire/wheel combo.
 

turkeybird56

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The tire pressure rating listed on the doorframe says tires should be 39 max psi.

If you get aftermarket tires like falken wildpeaks and the psi for the tire is listed at max 50, do you air them up to the max or stick with max 39 per the trucks specs.

Thanks!
ALL below just FYI. Running at MAX, argh, only when fully loaded. IMHO.

Falkens for 18" MSPF winter rated, max 51 psi. I tried running mine at 41, too ruff, went down to 39, so so, and I run 37-38 PSI, only air up to near MAX when I am pulling trailer loaded, and have max weight attached to vehicle. Running max gives U that very hard ride effect, IMHO.

ADDED: My numbers based on "C" rated tire, 18" rim, 275 65R 18.



///
275/65R18 is an Metric tire.

Use our tire pressure calculator to calculate proper tire inflation for replacement tires to match the original equipment tire load capacity on your vehicle.

275/65R18 116 SL is a Standard Load tire with a load index of 116 and a maximum tire load capacity of 2756 lbs @ 36 psi, capable of supporting up to 2756 pounds or 1250 kilograms when inflated to its maximum air pressure of 36 pounds per square inch (psi) or 248 kilopascals (kPa). ///
 
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turkeybird56

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Here is a Great Chart ref OEM tires, pressures:

 

MoparFin

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Draw a line on the tires across the tread with chalk. Drive it. Adjust air pressure till the chalk wears off evenly. Tire pressure listed on the truck is only for stock tires and exact replacements.

My tires are 35 x 12 1/2 r22. I run 55 psi, max listed on tire is 80.
 

Jane S

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The tire pressure rating listed on the doorframe says tires should be 39 max psi.

If you get aftermarket tires like falken wildpeaks and the psi for the tire is listed at max 50, do you air them up to the max or stick with max 39 per the trucks specs.

Thanks!

You inflate for the weight you want to support.

However, underinflation is bad - cause of many blowouts.
 

MADDOG

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I air up for weight, air down a bit for comfort when not loaded or towing and I have to be mindful of how much the PSI will grow driving on the freeway in summer heat.

The door sticker is a "suggestion" and doesn't have to be strictly followed.
 

CanuckRam1313

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40psi cold for front and rear is a great 'all around' setting that gets you in the zone of comfort, safety and loading for regular usage.

I personally check and adjust my tires cold at least monthly, and I get an alignment check and adjust at a minimum of annually, too.

I never have any feathering, scalloping, uneven, or center wear on my tires.
 

WY-Dave

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Draw a line on the tires across the tread with chalk. Drive it. Adjust air pressure till the chalk wears off evenly. Tire pressure listed on the truck is only for stock tires and exact replacements.

My tires are 35 x 12 1/2 r22. I run 55 psi, max listed on tire is 80.
Chalk test is the better way of doing it. Between the Magnum and Jeeps I went though about 6 different brands of tires. I contacted the manufactures each time and the response across the board was to follow the door sticker. On the Jeeps I did the chalk test and between the 4 brands, it would come out under +5psi from the door sticker.
 

Yarek

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As the first approximation you should go with the number listed on the truck, not the max for the tire.

If you wanna get scientific about it (which isn't all that hard actually), look up the tire's inflation vs. load table. You don't need a specific one for that particular tire. But you should be able to find a table for a tire with that load and speed index. Here is a chart for my tires for example:

from there, you take the truck's spec for the max load on the front and rear axles, divide each by 2 (2 tires per axle, right? unless you run 4 in the back), and then you see what pressure is required to support that kind of load. That would be the max pressure you use, unless you overload your truck regularly.

In my case, I run mine at 38psi front and rear. The 4 tires, at that pressure, would support close to 11,000 lbs. I get reasonably "good" mileage (8-11 mpg) and a relatively smooth ride. I could dial back a little, but sometimes I load that thing to its limits and I don't want to constantly run my little compressor on these relatively large tires.
 

craigsez

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Never use max pressure,tire will warm up and psi will increase,even when loaded i wouldnt max it out..Mind ya i would add a few psi and watch psi ga to see....
 

MoparFin

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Never use max pressure,tire will warm up and psi will increase,even when loaded i wouldnt max it out..Mind ya i would add a few psi and watch psi ga to see....
Max PSI listed on tires is for cold PSI, so even if you go up to the max, as long as you are measuring while tire is cold it is ok.
 

JF19Longhorn

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I went one size up (LT275/60R20) and from a P to a LT when I put the Mickey Thompsons on. I've been experimenting with pressures ranging from 38 - 45psi. While 38psi felt the best ride wise, it was alittle sloppy in the corners, so I'm currently sitting around 43 all around.

Online calculators said I should be in the 44-45psi range (unloaded).

I plan to go upto 60-65psi when towing this weekend.
 

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craigsez

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Max PSI listed on tires is for cold PSI, so even if you go up to the max, as long as you are measuring while tire is cold it is ok.

Yes tires are measured when cold...Depending on how you drive and load in the bed determines how quick and to what psi does when warm...Heck at say 36 psi cold not moveing,i have seen my tires go up a good 5-8 psi when truck sits in the sun....Nope i never max mine out..
 
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