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jp467 05-02-2011 06:05 PM

Tire Pressure
 
I was wondering what others are running for tire pressure. I have the 20 inch wheels and I know they say 36 cold. I have them set around 35 cold and as they warm they come up to 37. I leave it there because this is what they recommend but it just seems kind of high to me. I had the 18 inch wheels on my first wk2 and they were supposed to be 33 cold. Does anyone know why they want 36 for the 20 inch wheels. I would think we would get a better ride at 33. Any thoughts?

Nouveau Redneck 05-02-2011 07:19 PM

Re: Tire Pressure
 
Different tires have different characteristics and needs. 16 inch tires for a Dodge 3500 pickup truck take 45 psi. If you run tires at lower than the recommended pressure you may get a softer ride, but with the low profile sidewalls maybe not, and probably better grip on dry pavement, but you'll probably get uneven tread wear with the outsides of the tread wearing moe than the middle of the tread.

RageOfFury 05-02-2011 07:37 PM

Re: Tire Pressure
 
The sticker on the door says 33PSI on my Laredo. I, however, run my Goodyear SilentArmors at 35PSI.

Do NOT inflate your tires to the PSI rating on the tire itself, that's the MAX psi the tire can take.

Lingohocken 05-02-2011 08:35 PM

Re: Tire Pressure
 
Quote:

Originally Posted by Nouveau Redneck (Post 407951)
Different tires have different characteristics and needs. 16 inch tires for a Dodge 3500 pickup truck take 45 psi. If you run tires at lower than the recommended pressure you may get a softer ride, but with the low profile sidewalls maybe not, and probably better grip on dry pavement, but you'll probably get uneven tread wear with the outsides of the tread wearing moe than the middle of the tread.

With the 20" low profiles presumably there's a higher chance of sidewall and/or rim damage on potholes if inflation isn't at least at the recommended level. Better mileage and handling, too.

mjw930 05-02-2011 08:48 PM

Re: Tire Pressure
 
I have the 20" rims and changed out the Goodyears for Michelin Latitude Tour HP's. I run 36, as spec'd unless I'm towing, then I bump them up to 38 front, 40 rear. I use the temperature gain to determine if I'm at the optimum pressure. A tire will gain between 2 and 3 lbs between cold and hot. If they are all going up equally and no more than 3 degrees then you are at the proper pressure. If the front or rears go up more than the others then add 2 lbs to them and see if that makes them heat up equally.

When I tried 36/36 towing they went to 40/42. I knew that wasn't right and arrived at the numbers above and they work great. When I'm not towing I run 36/36 cold they heat up to 38/38, again, pretty much perfect.

You can also play with the pressures to adjust the handling and ride and, for the most part, not have any effect on tire wear. You would have to run upwards of 45 lbs in these radial to wear the center more than the outside. The biggest hit on mileage is under inflation. The reason under inflated tires heat up is due to increased friction. That same friction wears them out faster.

jp467 05-02-2011 08:58 PM

Re: Tire Pressure
 
Quote:

Originally Posted by mjw930 (Post 408020)
I have the 20" rims and changed out the Goodyears for Michelin Latitude Tour HP's. I run 36, as spec'd unless I'm towing, then I bump them up to 38 front, 40 rear. I use the temperature gain to determine if I'm at the optimum pressure. A tire will gain between 2 and 3 lbs between cold and hot. If they are all going up equally and no more than 3 degrees then you are at the proper pressure. If the front or rears go up more than the others then add 2 lbs to them and see if that makes them heat up equally.

When I tried 36/36 towing they went to 40/42. I knew that wasn't right and arrived at the numbers above and they work great. When I'm not towing I run 36/36 cold they heat up to 38/38, again, pretty much perfect.

You can also play with the pressures to adjust the handling and ride and, for the most part, not have any effect on tire wear. You would have to run upwards of 45 lbs in these radial to wear the center more than the outside. The biggest hit on mileage is under inflation. The reason under inflated tires heat up is due to increased friction. That same friction wears them out faster.


That's some good information. Mine do go up about 2 to 3 lbs when they warm up. I was just wondering about the ride. My Overland with the 20's has a stiffer ride than the Limited I had with the 18"s. I didn't know if it was the air suspension that made the difference or is it because this one has the lower profile tires. Then of course I know that tire pressure will make a difference also.

Red G8R 05-03-2011 10:45 AM

Re: Tire Pressure
 
Standard pressures recommended are 36 psi for 20" and 33 psi for 18".
I have 20" Forteras but use 18" Blizzaks for winter. Even with 33 psi in the Blizzaks, the ride is much harsher than the 20" Forteras at 36 psi. It all has to do with the tire characteristics and for this we have to rely on the manufacturers recommendations.


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