2009 -2014 F150 XLT Crew 4WD "LT C-Load Tire Option"
09-06-2015, 02:18 PM
#11
Senior Member
THANK YOU, you are the second person showing that 40 psi. I originally thought that was in error from Ford, but 2 out 2 suggests it's correct.
How's the ride, noise, vibration, and mileage? At 41 psi, my tires didn't seem right. Perhaps the difference between Load C and Load E tires.
At 40 psi, it has 2130 lbs weight rating per tire. That's 4260 lbs per axle which still exceeds the axle rating, but anything less than 35 psi will be under the 3850 lbs axle rating and potentially be a dangerous situation. Components can be pushed past limits a bit, tires can't from what I've seen happen to others. I'd like to have some cushion, at least more than 5 psi. Surprised Ford cut it so close when they didn't have to.
FYI, Government requires new trucks/cars to have TPMS and they're set to go off when PSI goes down by 25%. The funny thing is that if you go by P series 91% of rated load for SUVs and light trucks. That equals 47 psi on an LT tire. At 25% under that 47 psi, it equals 35 psi which is 1940 lbs rating or 3880 lbs axle rating. Anything lower will be under the 3850 lbs axle rating. With the OEM P series tire, at the 25% under inflation of 35 psi is 26 psi. The P tire at 26 psi rating at 91% is 2056 lbs / tire or 4112 lbs per axle.
So with the P series OEM tire, it will cover both the 3850 lbs rated and 4050 lbs rated axles. But using an LT tire will need to be even higher than 47 psi to cover the 4050 lbs rated axle at the 25% under the rated inflation psi.
The 40 psi for the Load C LT tire option just doesn't make sense to me, but it's there none the less.
How's the ride, noise, vibration, and mileage? At 41 psi, my tires didn't seem right. Perhaps the difference between Load C and Load E tires.
At 40 psi, it has 2130 lbs weight rating per tire. That's 4260 lbs per axle which still exceeds the axle rating, but anything less than 35 psi will be under the 3850 lbs axle rating and potentially be a dangerous situation. Components can be pushed past limits a bit, tires can't from what I've seen happen to others. I'd like to have some cushion, at least more than 5 psi. Surprised Ford cut it so close when they didn't have to.
FYI, Government requires new trucks/cars to have TPMS and they're set to go off when PSI goes down by 25%. The funny thing is that if you go by P series 91% of rated load for SUVs and light trucks. That equals 47 psi on an LT tire. At 25% under that 47 psi, it equals 35 psi which is 1940 lbs rating or 3880 lbs axle rating. Anything lower will be under the 3850 lbs axle rating. With the OEM P series tire, at the 25% under inflation of 35 psi is 26 psi. The P tire at 26 psi rating at 91% is 2056 lbs / tire or 4112 lbs per axle.
So with the P series OEM tire, it will cover both the 3850 lbs rated and 4050 lbs rated axles. But using an LT tire will need to be even higher than 47 psi to cover the 4050 lbs rated axle at the 25% under the rated inflation psi.
The 40 psi for the Load C LT tire option just doesn't make sense to me, but it's there none the less.
i'm running the stock goodyear wrangler at/s tires....I new I wanted a at/mt.. felt the tread would stand better to a truck... ride quality is good/low to no road noise...they seem to be holding up to the towing as well....another reason for no p-rated tire.....as for load...as long as it holds what I put in and don't go over my ratings...i'm happy...
09-07-2015, 12:24 PM
#12
Senior Member
Thread Starter
i'm running the stock goodyear wrangler at/s tires....I new I wanted a at/mt.. felt the tread would stand better to a truck... ride quality is good/low to no road noise...they seem to be holding up to the towing as well....another reason for no p-rated tire.....as for load...as long as it holds what I put in and don't go over my ratings...i'm happy...
Last edited by Mike Up; 09-07-2015 at 12:29 PM.
09-07-2015, 12:27 PM
#13
Senior Member
Thread Starter
Yes, but for good reason. My kids will be riding in the truck with me on normal daily trips and camping trips. I don't want to have the wrong psi in the tires to cause failure or lack of traction when I least expect it.
Since I get conflicting information from the maker, the sales/installer, and even replacement chart pressures, I'm left wondering.
Since I get conflicting information from the maker, the sales/installer, and even replacement chart pressures, I'm left wondering.
09-07-2015, 08:23 PM
#14
Yes, but for good reason. My kids will be riding in the truck with me on normal daily trips and camping trips. I don't want to have the wrong psi in the tires to cause failure or lack of traction when I least expect it.
Since I get conflicting information from the maker, the sales/installer, and even replacement chart pressures, I'm left wondering.
Since I get conflicting information from the maker, the sales/installer, and even replacement chart pressures, I'm left wondering.
Last edited by Loki 5.0; 09-07-2015 at 08:29 PM.
09-07-2015, 09:59 PM
#15
Senior Member
Thread Starter
I did do the chalk test. 55 psi was over inflated. Tires were hot so I don't know what the cold pressure will be in the morning but I'm guessing somewhere between 45 psi and 47 psi.
Since the manufacture keeps both tires at the same psi, I'm doing the same.
The front tire came out pretty much perfect with even wear on the chalk all the way across from driving in a straight line. The rear tires wore even all the way across to 3/8" from the edge of the tread. That 3/8" tread still had dark chalk while the rest was wore.
Since the tires are at the same pressure, show good even wear, and ride, vibration and noise seems to be still good, I'm going to leave it there. The rear axle isn't loaded with the trailer or gear right now so it will likely wear better when loaded. BUT I'm going to keep them at the same tire air pressure as Ford does that with OEM P series tires and the LT option LT C Load tires.
I guess the E load Tires may wear a bit different than the C load tire. When I get the cold air pressure in the morning, I'll post back.
Since the manufacture keeps both tires at the same psi, I'm doing the same.
The front tire came out pretty much perfect with even wear on the chalk all the way across from driving in a straight line. The rear tires wore even all the way across to 3/8" from the edge of the tread. That 3/8" tread still had dark chalk while the rest was wore.
Since the tires are at the same pressure, show good even wear, and ride, vibration and noise seems to be still good, I'm going to leave it there. The rear axle isn't loaded with the trailer or gear right now so it will likely wear better when loaded. BUT I'm going to keep them at the same tire air pressure as Ford does that with OEM P series tires and the LT option LT C Load tires.
I guess the E load Tires may wear a bit different than the C load tire. When I get the cold air pressure in the morning, I'll post back.
09-08-2015, 08:38 AM
#16
Senior Member
After looking at everything I could find on the subject, I landed on 50-53psi as where I wanted them to be. I am confident that within that range they can handle at least the same load as the stock (P-rated) tires.
I have not done a chalk test however my tires do appear to be wearing pretty evenly with somewhere between 35 and 40k on them so far.
I do have to remember to tell the service writer that I want 50psi in the tires when I go in for an oil change otherwise they drop it to 35.
I have not done a chalk test however my tires do appear to be wearing pretty evenly with somewhere between 35 and 40k on them so far.
I do have to remember to tell the service writer that I want 50psi in the tires when I go in for an oil change otherwise they drop it to 35.
09-08-2015, 08:30 PM
#18
Senior Member
Thread Starter
Last night when I did the chalk test, the tires were already hot and the pressure was 50 psi where it passed.
This morning, after the tires cooled, the cold air pressure was 45 psi. I will double check when ever it stops raining.
So far so good, a bit more vibration but that's most likely because more tread is in contact with the road. Noise and ride are pretty good.
Thanks everyone.
This morning, after the tires cooled, the cold air pressure was 45 psi. I will double check when ever it stops raining.
So far so good, a bit more vibration but that's most likely because more tread is in contact with the road. Noise and ride are pretty good.
Thanks everyone.
09-08-2015, 09:03 PM
#19
Senior Member
i hate to dis todays TECH's---parts changers....
back in my days we would balance recheck..... not bang weights on and throw tire back on vehicle and impact the nuts home....
back in my days we would balance recheck..... not bang weights on and throw tire back on vehicle and impact the nuts home....
09-09-2015, 10:58 PM
#20
Senior Member
Thread Starter
I emailed BFGoodrich about the correct tire pressure going from a P series to a LT series. They said the 47 psi is correct. Also said the prior phone rep was wrong at 55 psi.
Said Discount tires pressure of 41 was too low.
So I'll try the chalk test at 47 psi. Don't think 2 psi is going to change much.
Said Discount tires pressure of 41 was too low.
So I'll try the chalk test at 47 psi. Don't think 2 psi is going to change much.