Best tires pressure for long trip high way drive

[2005Expedition]

this is the tires, I take to the tires shop and both say its wrong kind of tires for my truck, those tires are usually for HD 2500 truck , but they both say stay at 35psi. Im confused

 

[Mediamonkey11]

Can't tell by the picture, but at least they're acknowledging the fact that those tires are the "wrong" rating for your Expedition. It's not the end of the world and if inflated correctly you are ok with the ride then it really doesn't matter. I don't however know why they would say to stay at 35PSI as they should know better. 35PSI is for the original rated tire that came on the truck, not for those.

Does the tire have a PLY Rating? My guess is it's a 10PLY. 50PSI Minimum! My work truck comes with stock 10 PLY tires and has a TMPS system, if the pressure drops below 70 PSI in back and/or 60 up front it goes nuts. It's for your safety!

 

[2005Expedition]

Can't tell by the picture, but at least they're acknowledging the fact that those tires are the "wrong" rating for your Expedition. It's not the end of the world and if inflated correctly you are ok with the ride then it really doesn't matter. I don't however know why they would say to stay at 35PSI as they should know better. 35PSI is for the original rated tire that came on the truck, not for those.

Does the tire have a PLY Rating? My guess is it's a 10PLY. 50PSI Minimum! My work truck comes with stock 10 PLY tires and has a TMPS system, if the pressure drops below 70 PSI in back and/or 60 up front it goes nuts. It's for your safety!

I dont think it had any PLY rating, I dont see it say any where on tires. I do google search and yes 35 psi is too low since its LT rating

http://www.toyotires.ca/sites/default/files/loadinflationtable.pdf

this is the tires, I had in now

http://www.pirelli.com/tire/us/en/suv/sheet/scorpion_str.html

 

[2005Expedition]

Thanks MR bean, 50PSI that it !!

 

[Mediamonkey11]

You got it! I have 8PLY Load range D tires on now and run them at 45psi, their max is 60, not the most comfortable but when I put them on the tire shop warned me to never go below 40, I was happy to hear them say that though

 

[ExpeditionAndy]

OP: PLEASE do not run anything lower than 50PSI in your tires, 46-47 at BARE minimum, yes it's going to be a bit more uncomfortable but you're not running the stock rated tire and therefore need to deal with those consequences. Upside is it gives you the possibility to have less rolling resistance and therefore slightly better mileage.

Are you referring to the temperature rating?

 

[Mediamonkey11]

Are you referring to the temperature rating?

Load rating/PLY rating

 

[ExpeditionAndy]

I can't find that anywhere on my tires. The only thing I can find is Max inflation 50 PSI. I have 275/60/R20 Cooper Zeon LTZ Tires and I can't find any specs on Cooper's website.

 

[Mediamonkey11]

I'm fairly sure the single letter rating applies mainly to LT (light truck) tires, see this site here: http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=55

Though with a max pressure of 50 psi my guess is you have load range C or 6 ply tires in which case you can run the recommended 35 psi cold per Ford's specification as that pressure is acceptable for that tire.

 

[Mediamonkey11]

Your markings may differ slightly per manufacturer but to be sold in the US they need to conform to load rating standards...

 

[2005Expedition]

LT 265-70R17 121/118S MS that all i see, i dont see any 8pr like your

 

[DRS1]

I will go ahead and call you out here, unfortunately you are incorrect.



The vehicle recommended tire pressures are based off of the same rating of tire being installed that came from the factory which should be a C or P rated tire (can't remember which). So, if the OP had factory rated tires, you'd be correct.



That being said, the OP sates that the maximum tire pressure rating on the tire is 80 PSI indicating that they have an E rated tire. These are usually reserved for larger trucks and are a bit overkill for the expy but hey, they work.



Tires require a certain minimum pressure to maintain structural integrity of the sidewall or else they will break down faster and risk the possibility of sidewall failure (blowout). Just give your local reputable tire dealer and they'll be able to confirm this...



The minimum pressure for a C rated tire is right about 30-32, for a D rated tires it about 40-45, and for E it's about 50 PSI. Anything lower than that on those is risking heat buildup and blowout, especially on long trips and ESPECIALLY in hotter climates. MANY more failures occur due to underinflation rather than overinflation. The only thing that is negatively affected by overinflating a tire is a higher rate of treadwear and an uncomfortable ride.



OP: PLEASE do not run anything lower than 50PSI in your tires, 46-47 at BARE minimum, yes it's going to be a bit more uncomfortable but you're not running the stock rated tire and therefore need to deal with those consequences. Upside is it gives you the possibility to have less rolling resistance and therefore slightly better mileage.

^^^ +1 I would go 20-25% higher as a typical lowest minimum that what he says above for pressures. I have a 2003 Eddie Bauer since new, with D rated tires and run at this rate. They wear just fine, lower rolling resistance, lower heat rise as measured (suggest you go to Home Depot and buy the pistol grip laser aimed temp reader. Works great on tires. You can check will towing or driving long trips any temp changes or problems before tire failure.

With my 2009 F350 KIng Ranch, believe I have E rated tires. When hauling, I run around 80lbs minimum cold. Running on 20" factory forged wheels.

In the 2003 when towing, is either a boat or horse trailer. The trailers are normally around 7000 lbs. the tongue weight being up to 1400 lbs and using a equalizer hitch. In the F350 I run a gooseneck with up to 8 horses and horse show tack gear. GVW and trailer will hit up to 26k easy, measured on a scale. The trailers have highest rates tires and call for up to 120lbs. Never run under 100 cold.

For you, assuming you keep the tires, running higher than you are is required per the design spec. For the reasons as he listed above. Plus you will pick up better mileage as rolling resistance is lower and you are not turning your gas into tire heat. The ride should not suffer much as they are designed to wear optimal and ride well at the higher pressures.

Hope this helps.

 

[2005Expedition]

thanks, I put 50psi this morning.

 

[2005Expedition]

just back from 1200 miles trips, all went well , relax and sleep now

 

[Mediamonkey11]

Mileage/load/speeds?

 

[2005Expedition]

just hauling family, 50psi all around ( no air lost, I check every morning while on the trip ), speed is 70-90 MPH 2-3 hours none stop.

 

[brilis]

I just put 4 brand new Nitto Terra Grappler AT tires on my 2004 Expy Eddie Bauer. Haven't even hit the road with them yet. On the Nitto site, they say to run replacement pressures of 35 lbs in front and rear.

I removed the OEM tires and rims which were 265/70/17, now running OEM Ford 275/55/20. Same 44 offset. I also think these might have come on some expy's.

I am not sure what the sidewall says, will check when I get home. So...Do I run the recommended pressures from Nitto?

Thanks.

 

[metaldrgn]

I didn't feel like reading all 4 pages of posts, but just from the first page I thought I'd chime in.

Ignore what the door says that's for stock tires. Fill up your tires to what your tires call for (max cold pressure). If it says 80 PSI then fill it to 80 PSI. It gives you optimal driving.

This is not only beneficial for good gas mileage, but more importantly for stopping distance especially for highway driving. The under-inflation image is partially inaccurate because more tire surface area will contact the road causing more friction reducing MPG and braking because when you hit the brakes, the tires will hop from the extra slop. Over-inflation will reduce the surface area contacting the road, but your braking distance will be longer (both apply to emergency braking only).

 

[ExpeditionAndy]

Hi Tony,

I did a little more research on my tires but I could not find a ply rating. These are the specs for the 275/60/R20 Cooper Zeon LTZ tires.

I would like to run a little higher pressure in hopes of lowering the rolling resistance and increasing gas mileage.

As near as I can tell, the tires are 5 ply in the tread and 2 on the sidewall.


Load Index: 119
UTQG: 520 A B
Load/Ply Rating: -
Maximum PSI: 50
Section Width: 10.80"
Tread Depth: 14
OE Specification: -
Performance Rating: S
Mileage Warranty: N/A
Load Capacity: 2,998 lbs
Sidewall: Black Wall
Overall Diameter: 33.00"
Tire Weight: 53.00 lbs
Item Number: 90000003474

 

[Mediamonkey11]

I wonder if the fact they're performance tires makes them in a different class regarding ply rating and load ratings... That said my suggestion would be to try 50 psi (because you won't hurt anything at the max psi), and if the ride is too firm then go down 5psi, it wouldn't hurt to do the chalk trick to make sure your contact patch isn't suffering, my bet is that at full pressure you'd be fine but just for kicks and grins it might be fun.

I always err on the side of high pressure if I can handle the ride and the contact patch is even.

The chalk trick is to take some sidewalk chalk and draw a thick line on the tire across the tread and roll over the line on flat cement to make sure the tire is flat on the ground and you're not ballooning or cupping (as illustrated by the picture above from mtldragon).