Tire load range and pressures

AMTRV

Member
I have a 2021 F150 Powerboost 4X4 with 3.73 gears that I pull an Opus OP15(6900lb gross) with. Wife and I do a lot of backcountry camping all over the southwest. We previously used a Ford Superduty with a 6.7L that was great for pulling off-road but a bit rough on my old bones for every day driving.
Currently I have stock 275/65 18s. I’m wanting to go with a LT tire in a 33-34” diameter as I could use a bit more ground clearance as a lot of the campsites we use are extremely rocky and rough.
My question is, can I run 35lb tire pressure in these E rated tires without ill effects? I’m pretty sure my load carrying capacity at this pressure will be fine with my rig....tell me if I’m wrong.
I love the way this truck rides with the factory SL rated tires but do not trust them on the rocks in the remote areas where we like to camp which is usually many miles from “help”.
I‘m 67 years old and no stranger to off-road driving and this is the first 1/2 ton truck I’ve owned in 40 years......we’ll, I did have a 17 Raptor for less than a year but it wouldn’t pull our Opus very well.....it just wasn’t practical for my use.
Thanks in advance.
Norris
 

Kmrtnsn

Explorer
Lower tire pressures off road are fine For exactly the reasons you state, air back up when you reach improved conditions. I’ll run as low as 12PSI off road but normally 15-20 depending on my loading.
 

AMTRV

Member
I’m sure I didn’t ask the correct question.
Is it ok to run 35lbs of pressure in an E rated tire for daily driving on a F150? That’s the recommended pressure on the door jamb tag.
 

Overdrive

Adventurer
If your original tires were "P" instead of LT tires, it will take some calculation to determine the pressure to run your new tires at. Did your truck come with E rated tires OEM? If not, the door sticker for inflation pressure no longer applies when you change to a different rating.

This document might put you to sleep, but for starters look at page 11--the red "Warning" box.

 

billiebob

Well-known member
I’m sure I didn’t ask the correct question.
Is it ok to run 35lbs of pressure in an E rated tire for daily driving on a F150? That’s the recommended pressure on the door jamb tag.
yes

tire pressure on the tire is max tire pressure at the max rated load. An E rated tire on a legally loaded F150 is likely overkill.

IF you bought the tires from a reputable local tire retailer they will give you the best advice on what tire pressure to run.
IF you saved $50 and bought the tires on line.......... well good luck with after sales service.

yes, 35psi on a legally loaded F150 should be fine. Technically an E Rated tire is a 1 ton, F350 tire, which require more psi to haul heavier loads which your F150 cannot legally carry.

But I say ask the guys who sold you the tires.
 
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To be more correct and not depend on people's guesses or opinions, if you find a tire go to the manufacture and they will have a load and pressure chart for the tire you have. Then look at the door for the axle weight ratings or get weighed to look up what load the pressure will support and go from there.

Below is a toyo one attached

Just being based off a e-rated tire is poor, since the weight rating will be different for each size, say 285 might be 3600lb and you go 295 it could be a 4000lb

Screenshot_20210224-223000.jpg
 

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AMTRV

Member
I’m probably going with a E rated tire because there are not many choices in a SL tire. Probably will go with 285/70 18. I had E rated 285/75 18s on all of my previous trucks because they were all Superdutys. Never had a problem with flats or cut sidewalls. This 1/2 ton changes everything. I want to keep the nice ride but also want to keep the strength needed to handle the rough trails that I encounter on almost every excursion.
Thanks for the above information. At least that answered my questions.
 

Mfitz

Member
I’m probably going with a E rated tire because there are not many choices in a SL tire. Probably will go with 285/70 18. I had E rated 285/75 18s on all of my previous trucks because they were all Superdutys. Never had a problem with flats or cut sidewalls. This 1/2 ton changes everything. I want to keep the nice ride but also want to keep the strength needed to handle the rough trails that I encounter on almost every excursion.
Thanks for the above information. At least that answered my questions.
I have an F150 and tow a travel trailer, not heavy (5K) but a big wind sail that I can feel when towing. My F150 came with stock tires that felt really mushy and unstable even inflated to their max when towing on twisty mtn roads and in heavy wind. I went to E rated tires and that all changed, feels very planted and stable in all conditions when towing. Empty ride is definitely more firm, some might say rough but I don't mind it. I have 285/70/17 in Cooper AT3LT right now and really like them. I run them at 40-42 unloaded, air up a bit in the rear for towing, air down for dirt roads.
 
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AMTRV

Member
I'm thinking the 285/70/17 sound pretty much like a good fit for me. I have some Raptor wheels(17X8.5) that I'm considering using, so this size tires would be just about perfect. A lot of guys rave about the Falken Wildpeak A/Ts so I may try them.
Our first trip of the year to Big Bend is coming up in 3-4 weeks so I need to get this new truck ready to go. There's a couple of spots on River Road that we like.....can't wait!
Thanks again for your help.
 
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Mfitz

Member
I'm thinking the 285/70/17 sound pretty much like a good fit for me. I have some Raptor wheels(17X8.5) that I'm considering using, so this size tires would be just about perfect. A lot of guys rave about the Falken Wildpeak A/Ts so I may try them.
Our first trip of the year to Big Bend is coming up in 3-4 weeks so I need to get this new truck ready to go. There's a couple of spots on River Road that we like.....can't wait!
Thanks again for your help.
I have my 285/70/17's on older Raptor takeoffs, I like the look. I almost got the Falkens, but the the Cooper AT3 XLT's were a little bit lighter and I was hoping to reduce weight from my old Yokohamas in 285/75 size. I don't think you can go wrong with either tire.
 

Inyo_man

Explorer
Daily driving with 35 lbs is fine with E rated tires (when unladen on a half ton).

Experiment with the pressure until you find your desired comfort level. Check the contact patch using the good 'ol fashion chalk method.

The E-loads will definitely hold up well in the rocks.
Cheers
 

AMTRV

Member
I’m have also considered the 255/80/17 Falkens. They are a tad taller and a tad narrower than the 275/70s. They will still fit a 8.5” wide wheel just fine. They may not look as good on my F150 as the wider 275/17s but I’m not really building this truck for looks and I like “tall skinnys”. I’ve run them in the past on a couple of Land Cruisers and they worked really well. Plus, I think they are a little lighter.....I need to check that though.
 

RoyJ

Adventurer
I’m sure I didn’t ask the correct question.
Is it ok to run 35lbs of pressure in an E rated tire for daily driving on a F150? That’s the recommended pressure on the door jamb tag.
An SL tire @ 35 psi carries more weight than an equal size E-rated @ 35 psi.

The best is to look up what your OEM tires carry @ 35 psi, then on Nitromethane's table, find an E-rated size that carries the same load @ 35 psi. You may have to upsize, which you plan on doing regardlesss.

I'd guess the 275/80R18 size, 2535 psi @ 35 psi, is a good fit.
 
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