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Super Genius
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I have the 07 DC Limited 6.5 bed with the factory 20" wheel upgrade. Comes with Bridgestone Dueller HT tires. The sticked on the driver door panel says 30 psi for front tires and 33 psi for rear tires. I have been driving my truck for about a month and never checked the actual pressure until today. The truck had been sitting cold for an hour or so, outside temp was 70 degrees at the time. Both front and rear measured 37 psi with a fairly good quality hand-held brass dial gauge.

I couldn't figure out why the dealer would have overinflated the tires so I let some air out until I hit 30 front and 33 rear. The front tires actually look a little more flat than the rear so I am wondering if I did the right thing. Why would the front have less psi than the rear? Wouldn't you want more psi in front to handle the weight of the motor? Another odd thing is the TPM warning system didn't go off even though I lost 7 psi in front (23% of factory target value) and 4 psi in rear (12% of factory target value). Just how much air do you have to lose to get a TPM warning? Do I need to recalibrate my TPM now that I let some air out?
 

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I have the 07 DC Limited 6.5 bed with the factory 20" wheel upgrade. Comes with Bridgestone Dueller HT tires. The sticked on the driver door panel says 30 psi for front tires and 33 psi for rear tires. I have been driving my truck for about a month and never checked the actual pressure until today. The truck had been sitting cold for an hour or so, outside temp was 70 degrees at the time. Both front and rear measured 37 psi with a fairly good quality hand-held brass dial gauge.

I couldn't figure out why the dealer would have overinflated the tires so I let some air out until I hit 30 front and 33 rear. The front tires actually look a little more flat than the rear so I am wondering if I did the right thing. Why would the front have less psi than the rear? Wouldn't you want more psi in front to handle the weight of the motor? Another odd thing is the TPM warning system didn't go off even though I lost 7 psi in front (23% of factory target value) and 4 psi in rear (12% of factory target value). Just how much air do you have to lose to get a TPM warning? Do I need to recalibrate my TPM now that I let some air out?
All very good questions. As there seems to be a lot of tire variations, I too am curious. I have 20's with Bridgestone Alenzo HL Duelers. Tag on door says 30 front 33 rear, which I checked and were correct from dealership. The front diffinitely looks lower than the rear, which is why I originally checked. This is a more performance oriented tire, but I cannot ever remember owning a vehicle with different tire pressure front and rear. For handling?

My previous Bridgestone Duelers (different type) ran 34lbs pressure front and rear. I guess the tire pressure warning will let you know your sitting on your rims!
 

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The rear tires have more air pressure because the manufacturer assumes that you'll be loading the rear of the truck to their max capacity. The same set up is true even for the 06's Tundra's. 29 for the front tires and 35 for the rear. But I increased the fronts to 40 psi. Less flexing, cooler temp tires, less wear, saves gas.
 

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I've had my CrewMax for a week now and yesterday was the first time I got a chance to check tire pressure. I was quite surprised to learn that my Truck had the correct pressure:confused: Normally dealers tend to over fill the tires. As a few of you have said, the fronts with the correct (30lb) pressure looked like it needed to be filled. I filled the fronts with 35lb and the rear with 37lb. It's always a good habit to fill your tires with about 5lbs more than the recommended tire pressure. It helps with rolling resistance. Reset the TMS and all is well.

Cheers:tu:
 

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If your not towing and running uneven front to rear tire pressures you are "pushing" the front set and therefore creating more rolling resistance and premature tire wear.
Toyo may can build a truck ? they know nothing about tires :rolleyes:
35 psi on all four corners,roatate ever 4k till the cheapo stockers start coming apart(and they will)
Then get some quality rubbers more suited for real truck life :cool:
 

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Super Genius
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Discussion Starter #7
35 psi on all four corners,roatate ever 4k till the cheapo stockers start coming apart(and they will)
Two posts that agree with over-inflating above the factory spec. I don't know much about tires but I tend to think this advice is correct. It just doesn't look right for the front tires to be sagging a little while the back tires are full up. It also doesn't make sense why the rear tires would be higher. Sure, you can load a lot of weight back there and they need to be ready, but what about the weight of the engine and front end, which can't be light at all? Surely they would call for more than 30? Also, why don't they explain the variable PSI in the manual and scale it based on load weights / driving conditions?
 

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I tried the factory recommended 30/33psi but the front end seemed to plow a bit.I finally settled on 35/35psi.This is with the 20" wheels and tires.
 

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Anything less than 36 psi in front has the fronts rolling over on the sidewalls in turns & less mpg's. Put a staight edge on top of the tire, on flat level concrete measure up from the ground to your straight edge (18's) this should be 30.875", go to the rear's measure the same way lower your pressure accordingly, when you hual heavy loads in the bed raise pressure accordingly.
I went with 36 front /28 rear, fr. 30.875"/ rear 31.120" sort of a comprimise on the rears so that I dont have to add press. for things like quads. that don't put the truck at max capacity.
On all the trucks I've had, past experiances prove too much rear tire press. will wear out the center of the tire prematurely:td:
 

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Anything less than 36 psi in front has the fronts rolling over on the sidewalls in turns & less mpg's. Put a staight edge on top of the tire, on flat level concrete measure up from the ground to your straight edge (18's) this should be 30.875", go to the rear's measure the same way lower your pressure accordingly, when you hual heavy loads in the bed raise pressure accordingly.
I went with 36 front /28 rear, fr. 30.875"/ rear 31.120" sort of a comprimise on the rears so that I dont have to add press. for things like quads. that don't put the truck at max capacity.
On all the trucks I've had, past experiances prove too much rear tire press. will wear out the center of the tire prematurely:td:
Serious questions. How did you come up with this method? Is this from a tire manufacture?
 

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I'm not saying it is wrong. I'd just like to know how you come up with the measurements and such. My TRD has larger tires than the standard 18s so I wanted to know how you came up with your height so I could apply the technique to my tires. I could also apply it to other vehicles if there is a formula or method to your madness.

Hey, 200% of zero is zero. No getting rich off this for me. :D
 

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Anything less than 36 psi in front has the fronts rolling over on the sidewalls in turns & less mpg's. Put a staight edge on top of the tire, on flat level concrete measure up from the ground to your straight edge (18's) this should be 30.875", go to the rear's measure the same way lower your pressure accordingly, when you hual heavy loads in the bed raise pressure accordingly.
I went with 36 front /28 rear, fr. 30.875"/ rear 31.120" sort of a comprimise on the rears so that I dont have to add press. for things like quads. that don't put the truck at max capacity.
On all the trucks I've had, past experiances prove too much rear tire press. will wear out the center of the tire prematurely:td:
This is wrong! You want a flat foot print (where the tire meets the road). Top of the tire has nothing to do with that because there is no weight on it. If you really want to see if your tires have the correct pressure in them for a flat foot print, paint the tread from sidewall to sidewall and about a quarter of the way around with chalk. Now roll the truck on level concrete until the tire makes a complete revolution. Next compare the chalk mark on the concrete and the chalk on the tire. You should get a uniform footprint all the way across. If only the middle is showing up, you've got too much pressure in them. If the sides are predominant, then you've got too little. Adjust the pressure and keep doing it until you've got a full uniform footprint.

The reason the front is different than the rear is because when LOADED, you'll need more air in the tires to have a full footprint. The manufacturer lists the psi for if you were loading the truck fully.

The other way is to mathematically figure out the correct psi. On the sidewall, the tire will list how much the tire can support at what psi (ie 2250 lbs at 60psi). On the door jamb, it'll list the weight of the truck front and rear. Take the front weight and divide it by 2. That will allow you to figure out how much psi it will take per tire up front. Do the same for the rear.
 

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LMAO !! Where Do you people come up with this $h*t ?
There are lots of professions where people think they excel,when in fact its just a matter of refusing to do it correctly.
35 psi on all four corners GOT IT !?!

:rolleyes:
:rolleyes:
:rolleyes:
:rolleyes:
:rolleyes:
:rolleyes:
:rolleyes:
 

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This is wrong! You want a flat foot print (where the tire meets the road).
PHP:
Top of the tire has nothing to do with that because there is no weight on it.:td:
If you really want to see if your tires have the correct pressure in them for a flat foot print, paint the tread from sidewall to sidewall and about a quarter of the way around with chalk. Now roll the truck on level concrete until the tire makes a complete revolution. Next compare the chalk mark on the concrete and the chalk on the tire. You should get a uniform footprint all the way across. If only the middle is showing up, you've got too much pressure in them. If the sides are predominant, then you've got too little. Adjust the pressure and keep doing it until you've got a full uniform footprint.

The reason the front is different than the rear is because when LOADED, you'll need more air in the tires to have a full footprint. The manufacturer lists the psi for if you were loading the truck fully.

The other way is to mathematically figure out the correct psi. On the sidewall, the tire will list how much the tire can support at what psi (ie 2250 lbs at 60psi). On the door jamb, it'll list the weight of the truck front and rear. Take the front weight and divide it by 2. That will allow you to figure out how much psi it will take per tire up front. Do the same for the rear.
Get a clue, I'm Not saying to measure the flatness of the top of the tire, What we are checking is the amount of flex in the sidewalls that does effect directly to the foot print on the ground
 

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Get a clue, I'm Not saying to measure the flatness of the top of the tire, What we are checking is the amount of flex in the sidewalls that does effect directly to the foot print on the ground
It would help us understand how you arrive at these numbers if you would explain your method. Again, I'm not saying it's wrong, I'd like to know how you come up with it.
 

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It would help us understand how you arrive at these numbers if you would explain your method. Again, I'm not saying it's wrong, I'd like to know how you come up with it.
There isin't a fomula for this!!! I have done this for a number of years.
It's more of a scientific experiment. What we are doing is measuring the amount of side wall flex by measuring from the ground to the top of the tire or you can do the same by measuring from the ground to the lower or upper edge of the rim or a wheel nut we are just measuring side wall flex. for Me it's more accurate & easier to measure to the top with a straight edge.
But 1st. we have to know a optimum wear pattern, (2) handleing, (3) ride quality.
1 Wear pattern can be checked over time OR with a temp. gun (after running the tires, geting them heated)
2 Handeling or feel can be checked too many ways to mention I look at the sidewalls for scuffing & can feel the tires squrm under you (I'm a race car driver)
3 some like a stiff ride some like the comfort (personel pref.

The factory calls for thirty in the front mine came with 36 & that felt great to me a little stiff but I'm ok with that as the fronts have the extra duty of changing direction of the vehicle. I tried 30 psi the tires rolled over too much in the curves & I live in an area with many winding roads hence I went with 36 in the front.
In the rear mfg.'s have to give you the maximum psi. as to be idiot proof I.E. if they gave multiple ratings for different loads surely someone would screw up & not adjust thier press. have a blow out, get a lawyer & sue the auto-maker.
So you have the correct profile for the front by testing, you now would want to duplicate this profie in the rear ( remember that sidewall flex has everything to do with the foot print on the road
I hope this helps
 

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Now we are getting somewhere. I seem to have missed one thing. How do you determine the amount of sidewall flex that is desired or at least a starting point?
 

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You might be a race car drive on PS2 but your butt-meter/slide-rule theory/formulas would have you in the wall more the Robby Gorden if applied to the Real World.
Did that "Richard Petty Driveing Experience" teach you all that ?
Name one Class that runs tires out like you describe ?
KMart parking lot "Drifters" ?
Fact: Nothing in SCCA
Fact: Nothing in ARCA
Fact: Nothing in Busch
Fact: Nothing in Cup
Fact: Nothing in Outlaws
Fact: Nothing in USAC
Nor F-1,Nor IRL,Nor Junior Dragsters:clown:
People that think like this and drive on public roads SCARE THE ":eek: :eek: :eek: :eek: " OUTTA ME !!

Put the pipe down and back away real slow . . . . :rolleyes:
 

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35 psi on all four corners.
Your tires will wear better and roll smoother.
Big mistake. Stick with the sticker. I used to work for a very Large tire manufacturer. Tire pressures are one of the most analyzed and engineered aspects of your vehicle. Tire pressure, shocks, springs, vehicle load etc. all work together to form a complete suspension system (anyone remember the Firestone/Exploder fiasco?)
K
 
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