Over inflated tires

[Kaderast]

Took delivery of my new Ram a few weeks ago, and today was scrolling through the vehicle info on the instrument cluster and noticed my tires were inflated to about 50 psi!

I live at about 7,000ft of elevation in CO, so can only assume they were inflated to a proper pressure at the factory in MI, but the thin mountain air "caused" the tire pressure to "increase"??? Kind of surprised the dealership didn't catch this on delivery, surely all the vehicles they get in have the same propblem.

 

[Richard320]

More likely the tech doing PDI has an air gauge that is off, and he never looked at the cluster.

 

[JCK_25]

I've been curious about PSI as well. Was previously running the stock tires (Bridgestone Duelers) at about 46 PSI (would occassionally inctease to 50 on highway). Got new tires (Cooper AT3's and they were inflated to 39 PSI. Gas mileage went way down and am not sure if I should increase PSI to the 44 Max it lists on the sidewalk before we head out for a road trip tomorrow. Also not sure if the mileage drop has anything to do with the slightly larger tires (went from 275/55/20 to 275/60/20) has anything to do with it since I noticed my speedometer is also off around 3 MPH at 60 MPH. Should I increase PSI or leave it at 39 knowing it'll "heat up" to 43 or 44 over the course of the road trip?

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[SD Rebel]

Took delivery of my new Ram a few weeks ago, and today was scrolling through the vehicle info on the instrument cluster and noticed my tires were inflated to about 50 psi!

I live at about 7,000ft of elevation in CO, so can only assume they were inflated to a proper pressure at the factory in MI, but the thin mountain air "caused" the tire pressure to "increase"??? Kind of surprised the dealership didn't catch this on delivery, surely all the vehicles they get in have the same propblem.

They were probably at 60 psi originally, which is the standard psi setting for RAMs sitting at the dealership to prevent flat spotting. The tech should have lowered them to the correct setting prior to delivery, but half the time they forget.

My guess is your tires likely slowly deflated down to 50 psi from 60 psi, and the techs never bothered to adjust them down to the correct level to I'm assuming 38 psi for 18" street tired trims.

Funny thing is that Rebels on the other hand are supposed to be set at 55 psi F / 45 psi R due to the A/T tires they have.

 

[SD Rebel]

I've been curious about PSI as well. Was previously running the stock tires (Bridgestone Duelers) at about 46 PSI (would occassionally inctease to 50 on highway). Got new tires (Cooper AT3's and they were inflated to 39 PSI. Gas mileage went way down and am not sure if I should increase PSI to the 44 Max it lists on the sidewalk before we head out for a road trip tomorrow. Also not sure if the mileage drop has anything to do with the slightly larger tires (went from 275/55/20 to 275/60/20) has anything to do with it since I noticed my speedometer is also off around 3 MPH at 60 MPH. Should I increase PSI or leave it at 39 knowing it'll "heat up" to 43 or 44 over the course of the road trip?

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Sidewall max pressure is not what you should go by, you should use the PSI setting on the driver's door jam, which shows the recommended PSI.

Recommended settings are always set cold. Wait until the tires are cool and not in the sunlight to get an accurate cold reading.

Tire increase will most definitely drop mpg. You went from just under 32" to a full 33" tire, it will be noticeable on mpg.

 

[JCK_25]

PSI settings on the door are always at cold setting. Wait until the tires are cool and not in the sunlight to get an accurate cold reading.

So I could inflate to 44 PSI when cold and not worry if they heat up to the upper 40s while traveling? Truck rides better IMO with higher PSI.

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[SD Rebel]

So I could inflate to 44 PSI when cold and not worry if they heat up to the upper 40s while traveling? Truck rides better IMO with higher PSI.

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Sure, tires typically gain 3-4 psi when hot, but that is expected with the cold settings used by the manufacturer.

 

[yankeefan31569]

whats everyones tire inflated too? mines around 38psi on all fours should i move up to 40?

 

[LaxDfns15]

So I could inflate to 44 PSI when cold and not worry if they heat up to the upper 40s while traveling? Truck rides better IMO with higher PSI.

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If the 44 is max listed on the sidewall of the tire you don't want it to be there cold OR hot. You will wear the center of your tread out, and you'll be buying new tires in 2 years. You went from road tires to AT tires, that's what's causing your MPG drop. If your door sticker says 35 PSI I'd recommend 40 for AT tires. That's what I ran on my Titan after moving from road to AT for years and they wore well. I run 52/42 front/rear on my Rebel, and the recommended is 55/45 like SD said.

 

[SD Rebel]

If the 44 is max listed on the sidewall of the tire you don't want it to be there cold OR hot. You will wear the center of your tread out, and you'll be buying new tires in 2 years. You went from road tires to AT tires, that's what's causing your MPG drop. If your door sticker says 35 PSI I'd recommend 40 for AT tires. That's what I ran on my Titan after moving from road to AT for years and they wore well. I run 52/42 front/rear on my Rebel, and the recommended is 55/45 like SD said.

I do the same on my Rebel, 52/42 because that's about as low as I can go without causing the low pressure warning to come on. Wear is fine, comfort is better.

 

[Malodave]

The Falkens have a Max of 50psi. Over the winter or cold nights the tires
would be at 32psi and raise up to 37-38 when warmed up. I want to go to
42psi cold to see if it increases the MPG.

Malodave

 

[Neurobit]

Dealers are notorious for overinflating tires. Set them tho what it shows on the jamb and call it a day.

 

[LaxDfns15]

The Falkens have a Max of 50psi. Over the winter or cold nights the tires
would be at 32psi and raise up to 37-38 when warmed up. I want to go to
42psi cold to see if it increases the MPG.

Malodave

Yeah if it's a max of 50 I'd say 40-42 is a good spot as long as they don't get too close to max when they're hot. The Duratracs are 80 psi max, and we're sitting at 55-58 hot, so think about that when you're running close to max pressure.

 

[MBDC]

I'm running 42 psi. On the freeway in this Texas heat, it climbs to around 44/45.

 

[pilottim]

Toyo has a great document showing how to calculate tire pressure when changing sizes or going from P-metric to LT, might help:

Toyo Inflation Tables

 

[Dusty1948]

Took delivery of my new Ram a few weeks ago, and today was scrolling through the vehicle info on the instrument cluster and noticed my tires were inflated to about 50 psi!

I live at about 7,000ft of elevation in CO, so can only assume they were inflated to a proper pressure at the factory in MI, but the thin mountain air "caused" the tire pressure to "increase"??? Kind of surprised the dealership didn't catch this on delivery, surely all the vehicles they get in have the same propblem.

When most vehicles leave the factory the tires are usually overinflated. that's because it's unknown how long the vehicle will be sitting before it's sold, and also to prevent flat spotting from sitting too long without moving. However, as others have mentioned the tires should be set at the recommended pressure before delivery.

To a certain point increasing tire pressure will reduce rolling resistance which will affect gas mileage positively, but going too far will increase tire wear in the center of the tread.

Regards,
Dusty
2019 Ram 1500 Billet Silver Laramie Quad Cab 2WD, 5.7 Hemi, 8HP75, 3.21 axle, 33 gallon fuel tank, factory dual exhaust, 18” wheels. Build date: 03 June 2018. Now at: 052404 miles.

 

[CogitoErgoLevo]

recommended pressure on mine is 36psi but i set them at 40psi. Max PSI on sidewall is 44
Truck feels better at 40 psi (to me)

 

[Night Rebel]

How does the dash tire gauges recalibrate? Drive around? I just checked mine and made them correct pressure but gauges are off sitting in the driveway.

 

[CogitoErgoLevo]

Take several miles of driving for tpms to adjust

 

[Night Rebel]

Take several miles of driving for tpms to adjust

Gotcha!