Thread Tools Display Modes
Old 08-03-2015, 08:09 PM   #1
Junior Member
Markwie's Avatar
Join Date: Apr 2015
Posts: 25
Tire pressure on 10 ply LT rated?

I recently upgraded my P series tires with a max inflation of 55psi to Toyo LT tires with a max inflation of 80psi. Now when towing I run at max PSI and even with my heavy TT the F150 tows very steady. Unladen however it's quite a bit more bouncy than with the old P tires. What inflation do folks typically run on these tires when not towing? How bout inflation for best MPG? 80 psi doesnt seem to be the best for mileage either.

My mileage kind of tanked with the tire swap, easily 2mpg overall lost when not towing. Seems about the same towing.

IIRC the tire shop initially inflated to 55psi but I could see some roll marks on the tires from cornering.

2015 Vibe 268RKS
2014 F150 Supercrew 4x4 3.5L EB 3:31 axle
1999 F350 Supercab V10 4x4 3.73 LS
Markwie is offline   Reply With Quote
Old 08-03-2015, 08:22 PM   #2
Senior Member
HONDAMAN174's Avatar
Join Date: Jun 2011
Location: Big brown desert
Posts: 1,989
Your mpg prob went down because they are heavier tires. When not towing, I run my d rated at 45 and 60 when towing.

2014 Stealth Evo 2850- "Woodstock"
2011 Toyota Tundra Rock Crawler TRD 5.7- "Clifford"
2013 Honda Accord Coupe V6 w/Track Pack- "Julia"

Just glad to get away
HONDAMAN174 is offline   Reply With Quote
Old 08-03-2015, 09:20 PM   #3
Senior Member
Join Date: Oct 2012
Location: Oregon
Posts: 413
You shouldn't run E rated tires at 80psi on a 1/2 ton. You only need what the tire needs for the load. When I ran E tires on my 2010 F150, Discount Tire said 45psi was all that's needed to handle the F150 RAWR of 4050 lbs. I ran them at 35 psi when empty. Ride suffered some but not bad. Running those tires at 80psi on a light weight truck will wear the centers out prematurely. You need to look up the inflation tables for your specific tire and use those numbers. There's a reason why 3/4 ton trucks have two different psi ratings. One is for a load and the other is running empty. You door placard should tell you the empty psi for your truck. JMO but I wouldn't run any more than 50psi in the tires when towing. Also chance are your stock rims aren't even rated for 80 psi.

FWIW my 2500 says 80 psi for max load. That's 6200lbs on the RAWR. Why would you need 80 psi for a lighter load of 4000lbs? Just saying. Adjust your psi accordingly.
goduc is offline   Reply With Quote
Old 08-03-2015, 11:18 PM   #4
Junior Member
Markwie's Avatar
Join Date: Apr 2015
Posts: 25
I found the Toyo specs and they show I should be in that 50psi range. I do however find the truck feels alot more stable with the tires aired up to max. I tow with right close to 4000 on the rear axle in an area known for pretty stout side winds. Next go round I'll try the 50psi in the gorge and see how it goes. The truck will sure ride smoother at lower pressures. I had no idea they posted inflation tables for loads. Thanks for that info. I guess I learn something new every now and then.
2015 Vibe 268RKS
2014 F150 Supercrew 4x4 3.5L EB 3:31 axle
1999 F350 Supercab V10 4x4 3.73 LS
Markwie is offline   Reply With Quote
Old 08-04-2015, 12:14 AM   #5
Senior Member
Tonkatoy77's Avatar
Join Date: Mar 2015
Location: North Plains, OR
Posts: 252
I will be heading through the Gorge on Friday. Going to be spending 11 days in NE Oregon. I get to test out my new Equalizer hitch. I kind of hope there is some good wind when I travel through just to see how the hitch does compared to the old Eazlift.

As far as your tires go, if your more comfortable at max psi, then run it there. Just remember that they won't wear as good. But it was mentioned earlier, make sure your wheels are rated to handle 80 psi.

Have fun, and maybe we will see each other at a local camp ground some day!

Sent from my iPhone using Tapatalk
2007 Chevy Duramax EFI Live and other supporting mods.
2015 Wildcat Maxx T26BHS

Nights camped 2015....23
Tonkatoy77 is offline   Reply With Quote
Old 08-04-2015, 02:36 AM   #6
Site Team
wmtire's Avatar
Join Date: Nov 2010
Location: Northeast Louisiana
Posts: 11,077

P tires and LT tires are two different animals. Toyo actually has an excellent article on determining air pressures between different types of tires, including when you change out the original equipment P tires to a LT tire.

Please note their warning on page 11 (copied below), and how LT tires require higher psi to carry the equivalent load of a P tire.


WARNING! Please note that size for size, LT metric tires require higher air pressures to carry equivalent loads of P-metric tires and that any failure to adjust air pressure to achieve the vehicle’s load requirements will result in tire fatigue and eventual tire failure due to excessive heat build up. Due to the higher PSI requirements of LT metric tires they may not be suitable for replacing O.E. P-metric tires because of the ride harshness that results from higher PSI requirements.
2011 Flagstaff 831 RLBSS

I've just ordered a chicken and an egg from Amazon.... I will keep you posted.
wmtire is online now   Reply With Quote
Old 08-04-2015, 04:12 AM   #7
Senior Member
Join Date: Oct 2013
Posts: 360
While your tires will be rated for more weight check to see if your rims can carry the same.
GOTTOYS is offline   Reply With Quote
Old 08-04-2015, 05:46 AM   #8
Senior Member
Join Date: Nov 2013
Location: crete,il /texas
Posts: 270
Good info from Toyo Tires Thanks Wmtire
Big Bill is offline   Reply With Quote
Old 08-04-2015, 08:37 AM   #9
Senior Member
Cover Dog's Avatar
Join Date: Jul 2013
Location: Chardon, Ohio
Posts: 322
Send a message via ICQ to Cover Dog
The truck in my signature came from the factory with E rated tires. The door sticker says to run 55 in the front and 60 in the rear.
Bill, Maura & Rosie the rescued Boston Terrier
2016 Winnegbago Adventurer 38Q
2014 CR-V EX-L w/Nav & Blue Ox & Ready Brute Elite

NRA Endowment Life Member & FMCA #455593
Cover Dog is offline   Reply With Quote
Old 08-04-2015, 09:23 AM   #10
Senior Member
Join Date: Feb 2013
Posts: 130
I will give a copy of text I used for different fora and topics, and saved so I dont have to write it again and again.
For you the weights must be determined as accurate a possible for the 2 situations , towing and not towing. These weights are the most tricky parts in determining the needed pressure. But If you only give the tires specifications I can also make a Pressure/loadcapacity list for them with use of my extra save formula , the american lists lead to to much loadcapacity for the pressure.

Tirepressure advice is all about load on tire and speed ( and sometimes about alighnment - camber angle).

So if you can give details of car and tires , I can calculate an advice pressure with some reserve for things like, pressure-loss in time, unequall loading R/L, incidental extra load, misreadings of pressure scales,and misyudging of weight, etc.

This is from tires next and can be read from sidewall:
Maximum load or loadindex.
Kind of tire to determine the AT-pressure/pressure needed for the maximum load up to maximum speed of tire, or if lower 160km/99m/h/reference-pressure, wich is not the maximum pressure of tire.
Maximum speed of tire, most given as letter ( Q=160km/99m/h,N=140km/86m/h fi)

If you have offroad or tires looking like that , with large profile blocs that cover a part of sidewall, also mention, they are allowed lesser deflection then a normal road tire, then the tire maker used to determine the maximum load (to my conclusion the case for the Bridgestone tires on Ford Explorer in the Ford/Firestone affaire).

If you cant find all of it give sises of tire and Loadkind, then I will google for it.

From car next and mostly can be found on same plate as the original pressure advices:
GAWR and GVWR ( Gross Axle/Vehicle Weight Rating)
But best would be to determine the real weights in your use on seperate tires or estimate it as acurate as possible, by weighing per wheel(pair) or axle.
Maximum speed , you dont go over for even a minute in your use, eventually different for different situations, for instance when towing or fully loaded.

This apart from trafic regulations, if you drive faster then allowed give that speed. Nature punnisches with tire-failure, police only with a penalty.

Give all that and I will calculate and give a picture of one of my filled in spreadsheets in my answer.

If other then original tires, indead as is already answered other advice is needed, a stiffer tire ( fi C-load instead of P-tire) needs a higher pressure for the same load, or the other way around, has lower loadcapacity for the same pressure.

Greatings from a Dutch pigheaded self-declared tire-pressure-specialist.

jadatis is offline   Reply With Quote

pressure, tire

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

» Virginia Campgrounds

Reviews provided by is not in any way associated with Forest River, Inc. or its associated RV manufacturing divisions.

Our Communities

Our communities encompass many different hobbies and interests, but each one is built on friendly, intelligent membership.

» More about our Communities

Automotive Communities

Our Automotive communities encompass many different makes and models. From U.S. domestics to European Saloons.

» More about our Automotive Communities

Marine Communities

Our Marine websites focus on Cruising and Sailing Vessels, including forums and the largest cruising Wiki project on the web today.

» More about our Marine Communities

Copyright 2002-2015 Social Knowledge, LLC All Rights Reserved.

All times are GMT -5. The time now is 09:03 AM.