Ruger
FRF Addict
MCR, you have a great future ahead of you in standup comedy!
Tire Pressure
- Thread starter TuckerTravis
- Start date
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Boss Hoss
FRF Addict
A huge oversight in most of the points made above is the weight that tire is carrying. Just because you have an E rated tire doesn't mean you have to automatically carry certain psi all the time. Anybody who's hauled heavy loads over the road knows you don't build up nearly the same amount of heat in a tire (which, by the way, is what destroys a tire at speed- not flex) loaded as when unloaded. PSI becomes MUCH more critical when you're running close to that specific tire's maximum carrying capacity. Speed plays a huge role as well, but we're discussing psi.
Also, someone mentioned the numbers on the side of the tire. Those are MAX INFLATION numbers!
WRRRROOOOOOOGGGGGG! On many counts where do you want me to start here----now are you ready to take it like a man before we start?? Please think about this because I don't want to hurt your feelings early and then you get mad and run away.
OP
OP
TuckerTravis
Full Access Member
lets hear it.
Madcowranch
Genetically Modified
PropDr
FRF Addict
The OEM tire pressure recommendation is heavily influenced by gas mileage and is for the tire supplied by the OEM.
If you change to a different tire (different load rating or size, or both) the pressure needs to change.
Higher load rating lower pressure, lower load rating higher pressure; larger footprint lower pressure, smaller footprint higher pressure.
Note: These are only the major factors for normal driving!
If you change to a different tire (different load rating or size, or both) the pressure needs to change.
Higher load rating lower pressure, lower load rating higher pressure; larger footprint lower pressure, smaller footprint higher pressure.
Note: These are only the major factors for normal driving!
BigScott
Banned
As close as you are to the TX Rap Run, I say we continue that disscussion on the 13th of this month !
Boss Hoss
FRF Addict
Oh hell yes we can continue the discussions at the run. Will not have any of the engineers with me but it will be a fun discussion. Called me a “condescending ****”—hurt my feelings lol!
Just a little insight here but what happens when running the lower pressures and this is subjective dependent on the specific tire, load rating and let’s assume for the discussion that we are not hauling a load and that the truck is the Raptor not a Cummins for example that is heavier in the front. The carcass is made to bear the load of the vehicle and payload which means the commensurate area of the sidewall that flexes which is cause by decreased air pressure deflects the most is increased in a smaller area. Over time and given the normal heat cycling that goes on along with the smaller area receiving the most amount of deflection (more heat) due to the decreased air pressure can possibly begin to delaminate which weakens the sidewall and will ultimately cause a failure.
Just got finished meeting with our head engineer in this area who I have worked with as well as his predecessor for many years did say that “it would take an applications engineer at the manufacturer to determine what the minimum AP for the load to determine what is safe”. Read between the lines here folks----should you worry about running a no payload tire say slightly lower than the psi cold for maximum load carrying ability? Hell no it does not hurt because I did it for years but never more than 10 to 15% and that was with no load. If I was going on a long trip or carrying a load it was at max psi cold. Now I use nitrogen due to the fact that it does not seep through the carcass as easy as air because the molecules are larger and there is no moisture to speak of. Personally my ride is not too harsh running the max psi (firm is good for me) cold which also give me better mpg’s.
Just a little insight here but what happens when running the lower pressures and this is subjective dependent on the specific tire, load rating and let’s assume for the discussion that we are not hauling a load and that the truck is the Raptor not a Cummins for example that is heavier in the front. The carcass is made to bear the load of the vehicle and payload which means the commensurate area of the sidewall that flexes which is cause by decreased air pressure deflects the most is increased in a smaller area. Over time and given the normal heat cycling that goes on along with the smaller area receiving the most amount of deflection (more heat) due to the decreased air pressure can possibly begin to delaminate which weakens the sidewall and will ultimately cause a failure.
Just got finished meeting with our head engineer in this area who I have worked with as well as his predecessor for many years did say that “it would take an applications engineer at the manufacturer to determine what the minimum AP for the load to determine what is safe”. Read between the lines here folks----should you worry about running a no payload tire say slightly lower than the psi cold for maximum load carrying ability? Hell no it does not hurt because I did it for years but never more than 10 to 15% and that was with no load. If I was going on a long trip or carrying a load it was at max psi cold. Now I use nitrogen due to the fact that it does not seep through the carcass as easy as air because the molecules are larger and there is no moisture to speak of. Personally my ride is not too harsh running the max psi (firm is good for me) cold which also give me better mpg’s.
Ruger
FRF Addict
Boss Hoss, at max rated PSI, do you still get even wear across the tire tread? I would think that the tire would wear more in the middle of the tread from running unloaded at max rated PSI.
FilthyRaptor
Full Access Member
I'll tell ya what, the first 400 miles on my truck were at 50psi and the inside and outside of all 4 tires haven't even touched the ground. The nubs are brand new and still have the dealers tire shine on them.
I just don't know how low I can go. I'm at 42 now and it rides way better but haven't got enough miles at this pressure to make a statement on wear. I can say now it is just using all of the tire now.
I just don't know how low I can go. I'm at 42 now and it rides way better but haven't got enough miles at this pressure to make a statement on wear. I can say now it is just using all of the tire now.
Boss Hoss
FRF Addict
Depends on the wheel width and the individual tire--on all fitments there is a range of width you have to work with on the wheel. Currently at 50PSI mine are barely touching the outside took a week for the **** to wear off---I should have .5 wider rim but this rim is acceptable. The MTR's wore pretty even (at first when they were a lot stiffer they were a little more center biased) on these rims and the Yoko's will as well hopefully. Most of my other trucks were oil burners and heavier in the front than this one.
What is fun to watch is when they put the 4 hoses on the tires when the nitrogen is being put in. The machine takes the tires down to about 5 psi then fills them up with nitrogen to in this case 50 psi then purges back to 5 then back to 50psi.
The sidewalls and I have watched several sets do this really start to sag at a certain point when airing down. Funny not much sag from 50 to 40 but 30 (mine are 37's) it really looks like it is going flat. Different tires esp with the lower profiles it is not as apparent due to the shorter and stiffer sidewall.
---------- Post added at 11:21 AM ---------- Previous post was at 11:15 AM ----------
If you are at 42 cold on a unloaded truck even 42 front 40 rear I personally would not worry about it. That is just me but that would be my limit without more data from the manufacturer----funny but most of the time my trucks handled better at max psi cold or close to it. THAT is of course depending on the rim as well. Folks who try and put the wide tire on the narrowest rim they can always have handling issues.
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