Tire Pressure
Postmaster
Joined: Aug 2006
Posts: 2,829
Likes: 3
Originally Posted by havasulew
This info was provided to me by BFG through their customer service system. First I e-mailed, they provided a phone number to call. Spoke to a supervisor and this is the info they provided.
BFG 305-65-18 AT KO
40psi---------2470lbs
45psi---------2680lbs
50psi---------2910lbs
55psi---------3085lbs
60psi---------3280lbs
65psi---------3525lbs
I'm running a 2008 F-350 CC LWB with the diesel.
Front axle weight is 5460lbs
Rear axle weight is 3680lbs
Total weight is 9140lbs
Front psi is 55lbs
Rear psi is 50lbs
Yes, ride is somewhat comfortable. I'm 55 years old, I kind of like it. I don't notice any steering problems. No obvious over/understeer and no bump steer. I will be adding 5psi before I leave for Colorado to hunt in a couple of weeks.
BFG 305-65-18 AT KO
40psi---------2470lbs
45psi---------2680lbs
50psi---------2910lbs
55psi---------3085lbs
60psi---------3280lbs
65psi---------3525lbs
I'm running a 2008 F-350 CC LWB with the diesel.
Front axle weight is 5460lbs
Rear axle weight is 3680lbs
Total weight is 9140lbs
Front psi is 55lbs
Rear psi is 50lbs
Yes, ride is somewhat comfortable. I'm 55 years old, I kind of like it. I don't notice any steering problems. No obvious over/understeer and no bump steer. I will be adding 5psi before I leave for Colorado to hunt in a couple of weeks.
Based on your scaled weights I would say that your psi's are right on par and there would be no need to add any more psi.
The thing that concerns me though is the weight of your truck, especially on the front axle. Your trucks front axle has a GAWR of 6000 lbs and your front springs are either 5200 lbs, 5600 lbs or 6000 lbs, depending on options. With 5460 lbs on the front axle, you could already be overloading your springs and are very near max load for the axle.
Your trucks gross weight is nearly 1000 lbs over the average for a unloaded F-350 and most of that weight seems to have ended up on the front axle. Now I am curious as to what you got hanging off the front end.
I recently scaled a loaded '08 F-450 4X4 KR that was full of fuel with myself and another person at just under 9500 lbs.
Postmaster
Joined: Aug 2006
Posts: 2,829
Likes: 3
Originally Posted by High-C
Anyone running the All Terrains? I'm running 285/70-17's and I just installed them. I haven't had a chance to find the "right" tire pressure...
35 psi - 2105 lbs.
40 psi - 2315 lbs.
45 psi - 2510 lbs.
50 psi - 2755 lbs. - Load Range C
55 psi - 2890 lbs.
60 psi - 3070 lbs.
65 psi - 3195 lbs. - Load Range D
My "guess" is that you would want to run about 60 psi front and between 50 psi and 60 psi in the rear. We could be allot more accurate if we knew more about your truck.
Junior User
Joined: Feb 2007
Posts: 72
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PowerStrokeHD----I have the 6000lb front axle. Weight disribution is a bit off. The truck has the camper spring option which is one or two up from stock in the front. Also chose the 11,500GVW option (sure glad I did that). Not sure what the added weight of the PSD is but it sure makes the front heavy. I do have a Reunel front bumper which is about 300lbs net increase. I installed a tool chest in the bed that has a small winch for dragging deer and elk into the truck. The toolchest also is full of everything for everything if you know what I mean. The rear bumper is also Reunel which requires removal of the Ford trailer hitch. The bumper receiver is 3in above the stock hitch receiver which increases departure angle and increases tow capacity from 12,500lbs to 20,000lbs. Overall, I'm very happy with this truck across the board. The only problem I've had is soft sand in 2wd. There just isn't enough weight in the rear to move the truck. When I get in the mountains with an additional 1000lbs in the bed I think it will be great truck.
Postmaster
Joined: Aug 2006
Posts: 2,829
Likes: 3
Originally Posted by havasulew
PowerStrokeHD----I have the 6000lb front axle. Weight disribution is a bit off. The truck has the camper spring option which is one or two up from stock in the front. Also chose the 11,500GVW option (sure glad I did that). Not sure what the added weight of the PSD is but it sure makes the front heavy. I do have a Reunel front bumper which is about 300lbs net increase. I installed a tool chest in the bed that has a small winch for dragging deer and elk into the truck. The toolchest also is full of everything for everything if you know what I mean. The rear bumper is also Reunel which requires removal of the Ford trailer hitch. The bumper receiver is 3in above the stock hitch receiver which increases departure angle and increases tow capacity from 12,500lbs to 20,000lbs. Overall, I'm very happy with this truck across the board. The only problem I've had is soft sand in 2wd. There just isn't enough weight in the rear to move the truck. When I get in the mountains with an additional 1000lbs in the bed I think it will be great truck.
Well with the Reunel up front I can see where some of the extra weight it coming from. I still would be keeping a eye on the front axle weights though.
I understand that you have a 6000 lb front axle, that would be standard for 4X4 F-250's and F-350's. The thing you have to watch is the springs, as in most cases they will be rated for less then the axle.
The default GVWR for a SRW CC PSD 350 is 11,500 and the default front front springs are rated at 5200 lbs. With the camper package and the PSD the springs are upgraded by 1 level, so you should have 5600 lb springs. With your current scale weights you are going to have to be extremely careful as not to overload your front.
The average '08 350 PSD like yours will scale at about 4800 lbs on the front axle, unloaded.
Postmaster
Joined: Aug 2006
Posts: 2,829
Likes: 3
Originally Posted by farnorthdan
Sorry for the lack of info guys...BFGoodrich All-terrain T/A-KO...LT 305/55R20's on 20" XD rockstars flat black. Should I be running at max tire Pressure? (which is 65psi cold)
35 psi - 2095
40 psi - 2235
45 psi - 2425
50 psi - 2680
55 psi - 2795
60 psi - 2970
65 psi - 3195
I would try running the fronts at 60 psi and only bump it up to 65 if necessary. The rears I would stay in the 50 psi - 60 psi range. That will depend on what you use your truck for and how much load you carry.
Postmaster
Joined: Aug 2006
Posts: 2,829
Likes: 3
Originally Posted by RedBoat
I am running BFG All terrain TA KO's 285/70r-16's and I have found the best pressure is at 70psi front and back. I have also ran them at 5psi increments between 50 and 80psi to find the best ride quality and still have good tire wear. At 70 psi I wear the centers on the rear tires a little more than the fronts but the ride quality is much better. Less air in them makes the ride too mushy and unresponsive wile running them at 80psi makes it feel like your riding a rock! Try 70psi and see how you like it.
Postmaster
Joined: Aug 2006
Posts: 2,829
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Postmaster
Joined: Dec 2003
Posts: 4,196
Likes: 10
From: Arizona
Seems there is some confusion in this thread that needs to be addressed.
1) If you are running OEM size tires on your truck you need to follow the Cold air pressures listed on the "Safety Compliance Certification Label" located on the drivers B-pillar.
2) If you replace your tires with a size other than the OEM factory tires, then you need to use Load/Inflation tables to determine the proper cold inflation pressure to run in your tires to support the GAWR located on the "Safety Compliance Certification Label".
If you replace your tires with a tire that has less load capacity (ie replace "E" with "D" rated) you will have to lower the GAW & GVW you carry.
NEVER inflate your tires to more than the Cold Max Inflation pressure stamped on the sidewall of the tire.
NEVER Load the axles beyond the capacity of the Max Load rating of the tires as stamped on the sidewall of the tire.
Failure to follow these guidelines can result in premature tire failure, ill handling vehicle and potentially cause you to lose control of the vehicle.
1) If you are running OEM size tires on your truck you need to follow the Cold air pressures listed on the "Safety Compliance Certification Label" located on the drivers B-pillar.
2) If you replace your tires with a size other than the OEM factory tires, then you need to use Load/Inflation tables to determine the proper cold inflation pressure to run in your tires to support the GAWR located on the "Safety Compliance Certification Label".
If you replace your tires with a tire that has less load capacity (ie replace "E" with "D" rated) you will have to lower the GAW & GVW you carry.
NEVER inflate your tires to more than the Cold Max Inflation pressure stamped on the sidewall of the tire.
NEVER Load the axles beyond the capacity of the Max Load rating of the tires as stamped on the sidewall of the tire.
Failure to follow these guidelines can result in premature tire failure, ill handling vehicle and potentially cause you to lose control of the vehicle.
Freshman User
Joined: Jan 2002
Posts: 37
Likes: 0
From: Whitefish Bay, WI
I know I'm joining this thread a little late, but hopefully I can get some advice.
I recently put new tires on my truck. They are 285/70 R 17 Nitto Terra Grappler, Load Range E. They have a cold max inflation load of 3750 lbs.
The load table for LT285/70R17 is:
35 psi - 2105
40 psi - 2315
45 psi - 2510
50 psi - 2755
55 psi - 2890
60 psi - 3070
65 psi - 3195
70 psi - 3415
75 psi - 3525
80 psi - 3750
The stock tires were LT265/70R17 at 75 psi for load capacity of 3100. Using some linear interpolation on the 285 chart, I come up with a pressure of approximately 61 psi to equal the factory loading.
Now here comes the question. What tire pressure should I run? 61? 75? Something else?
I am running empty most of the time. My tire priorities, ranked by importance would be:
1)MPG
2)Traction
3)Tire Wear
4)Ride Comfort
Sorry for the long post, but I appreciate any help
I recently put new tires on my truck. They are 285/70 R 17 Nitto Terra Grappler, Load Range E. They have a cold max inflation load of 3750 lbs.
The load table for LT285/70R17 is:
35 psi - 2105
40 psi - 2315
45 psi - 2510
50 psi - 2755
55 psi - 2890
60 psi - 3070
65 psi - 3195
70 psi - 3415
75 psi - 3525
80 psi - 3750
The stock tires were LT265/70R17 at 75 psi for load capacity of 3100. Using some linear interpolation on the 285 chart, I come up with a pressure of approximately 61 psi to equal the factory loading.
Now here comes the question. What tire pressure should I run? 61? 75? Something else?
I am running empty most of the time. My tire priorities, ranked by importance would be:
1)MPG
2)Traction
3)Tire Wear
4)Ride Comfort
Sorry for the long post, but I appreciate any help
Thread Starter
|
FTE Leadership Emeritus
Joined: Sep 2000
Posts: 23,174
Likes: 1,678
From: Stephensville WI
I would start at 60 and test drive at 5 PSI increments until you find the pressure you can live with.
Also, remember the front and back do not have to match. Unloaded your rear tires carry less weight.
Also, remember the front and back do not have to match. Unloaded your rear tires carry less weight.
Freshman User
Joined: Jan 2002
Posts: 37
Likes: 0
From: Whitefish Bay, WI
I suppose I should have said the truck is 2005 F250, CC SB 4x4 Diesel Lariat.
I scaled it and I am running around 7900lbs. I belive it was around 4500 front, 3400 Rear. Nice to have scale at work.
I scaled it and I am running around 7900lbs. I belive it was around 4500 front, 3400 Rear. Nice to have scale at work.
Postmaster
Joined: Jan 2005
Posts: 4,743
Likes: 3
From: Peoria, IL
Originally Posted by UWMtriebs
I suppose I should have said the truck is 2005 F250, CC SB 4x4 Diesel Lariat.
I scaled it and I am running around 7900lbs. I belive it was around 4500 front, 3400 Rear. Nice to have scale at work.
I scaled it and I am running around 7900lbs. I belive it was around 4500 front, 3400 Rear. Nice to have scale at work.
Just remember, you will have to air up the tires if you are going to carry a load heavier than your normal one.
Senior User
Joined: Aug 2008
Posts: 348
Likes: 0
From: CA
Very interesting and important thread
So, for an 08 F250 CC SB FX4 6.4L PSD on OEM 275/65/20 Wranglers with 10,500GVWR it seems that the best balance between safety (avoiding death wobble) and ride comfort would be 70PSI front and 65PSI rear when unloaded/lightly loaded.
Please chime in at will on whether or not my conclusions are correct. I will have loved ones borrowing the truck over Christmas so really want to have it set up just right.
Thanks guys.
Please chime in at will on whether or not my conclusions are correct. I will have loved ones borrowing the truck over Christmas so really want to have it set up just right.
Thanks guys.
Last edited by Carl Lassiter; Oct 15, 2008 at 06:17 PM. Reason: added GVRW
Posting Guru
Joined: May 2006
Posts: 1,889
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From: MACON, GA
Too early for me. I had to go thru the thread and then realized it was posted almost a year ago. Norm, aka Redford is over in the Afghanistan mountains for a year. I miss his regular contributions, as I read from him that he has difficulty getting an internet connection.