Recommend Tire Pressures For Alternate Sizes

[slowmachine]

I cannot find tire pressure specs for the various wheel/tire combinations in either the printed owner’s manual or the digital download version. Given that Ford sells multiple sizes of wheels and tires as accessories, do they provide an addendum with accessory wheels? I don’t remember any manual in the last couple decades that didn’t have pressure specs for every OE wheel/tire combo for the car. This seems like a significant omission from the owner’s manual. Are they all 30 PSI?

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[P. A. Schilke]

I cannot find tire pressure specs for the various wheel/tire combinations in either the printed owner’s manual or the digital download version. Given that Ford sells multiple sizes of wheels and tires as accessories, do they provide an addendum with accessory wheels? I don’t remember any manual in the last couple decades that didn’t have pressure specs for every OE wheel/tire combo for the car. This seems like a significant omission from the owner’s manual. Are they all 30 PSI?

Hi Mike,

Tire/Wheel combinations are subject to change and therefore are no longer printed in the owners manual...most folks have no clue what tire they have on their vehicle. The required label on your left door jamb is your guide.

Best,
Phil Schilke
Ranger Vehicle Engineering
Ford Motor Co. Retired

 

[Frenchy]

I agree with Phil on this one. My stock size(255/65-17) calls for 30 psi and for my current size(265/70-17) I still run 30 psi. I dont have any issues with wear or comfort or traction. The best you can do is start with what the door placard and adjust from there. If you have a bigger tire you might want to consider slightly lower psi but no promises on the results.

 

[slowmachine]

I understand that Ford cannot possibly publish tire pressure recommendations for every tire size on the market. I’m looking for the Original Equipment sizes. This kind of information used to be, and still should be, included in the dumbed-down owner’s manual. If Ford recommends the same pressure setting for every OE combination of wheels and tires (like Toyota does with the Tacoma) it would be esay for them to say so. How do I know? It’s in their owner’s manual. I don’t think that manufacturers have much leeway in what information appears on the door jamb sticker, but there is plenty of room in the owner’s manual. What if I want a set of accessory wheels from the Ford dealer, and they are not the same size as the wheels installed at the factory? Owner‘s manual. Second set of wheels for snow tires? Owner’s manual. They even list the sizes of tires that will work with snow chains in the manual. No pressure settings. Ford could do better.

 

[Cape Cruiser]

I understand that Ford cannot possibly publish tire pressure recommendations for every tire size on the market. I’m looking for the Original Equipment sizes. This kind of information used to be, and still should be, included in the dumbed-down owner’s manual. If Ford recommends the same pressure setting for every OE combination of wheels and tires (like Toyota does with the Tacoma) it would be esay for them to say so. How do I know? It’s in their owner’s manual. I don’t think that manufacturers have much leeway in what information appears on the door jamb sticker, but there is plenty of room in the owner’s manual. What if I want a set of accessory wheels from the Ford dealer, and they are not the same size as the wheels installed at the factory? Owner‘s manual. Second set of wheels for snow tires? Owner’s manual. They even list the sizes of tires that will work with snow chains in the manual. No pressure settings. Ford could do better.

The ranger has several different tire pressures for different size tires

 

[P. A. Schilke]

The ranger has several different tire pressures for different size tires

I understand that Ford cannot possibly publish tire pressure recommendations for every tire size on the market. I’m looking for the Original Equipment sizes. This kind of information used to be, and still should be, included in the dumbed-down owner’s manual. If Ford recommends the same pressure setting for every OE combination of wheels and tires (like Toyota does with the Tacoma) it would be esay for them to say so. How do I know? It’s in their owner’s manual. I don’t think that manufacturers have much leeway in what information appears on the door jamb sticker, but there is plenty of room in the owner’s manual. What if I want a set of accessory wheels from the Ford dealer, and they are not the same size as the wheels installed at the factory? Owner‘s manual. Second set of wheels for snow tires? Owner’s manual. They even list the sizes of tires that will work with snow chains in the manual. No pressure settings. Ford could do better.

Hi Mike,

A back story.... Our CEO at the time, the ego driven Jaques Nassar, got into a firefight with the CEO of Firestone over the Wilderness AT tire on the Explorer due tire failure, resulting in tire blowout and sever accidents. Firestone CEO, Lampe, claimed the Explorer was poorly designed...Nassar claimed the tire was at fault, so the first edict from Nassar was to eleminate the Firestone Wilderness AT from all Ford Vehicles...Guess what...100% of Ranger 4x4a were on this tire. We headed to purchasing to see who in the tire manufacturers could support Ranger...then before we could make the decision, a further edict was to eliminate Firestone tires from all Ford production and to create a recommended list of other manufacturer tires for people driving vehicles that were still on OEM shipped Firestone tires. This created two problems. How to support production of new Rangers at a volume of 340,000 units a year times 4 tires per vehicle...and how to create a list of Ford certified replacement tires for a huge volume of vehicles on the road. Okay...the production support is detailed in another thread, but here is my point for the after sales replacement of Firestone tires.

My vehicle dynamics engineers had to certify by testing each tire for this list of replacement tires. This was a major headache with the volume of testing needed, but slowly but surely we chipped away at the tires of the sizes for Ranger 4x2 and 4x4. As part of the testing, the engineers had to determine the tire pressure for the specific tire, brand and design. The pressures were all over the map. 30 psi, 32 psi, 40 psi etc. The matrix of the tires grew to over some 40 different tires. Thus it became impossible to incorporate all these tires into the owners manual.

So the take away is your postulation of purchasing OEM wheels in another diameter for the tires of your choice is very rare. If you choose this route, the Ford Dealer is your guide to the tire pressure you need if the tire manufacturer does not have a recommendation. For such a scenario, your door label many or may not be correct as you modified your vehicle from as built. Tire Manufacturer of tires of the same size as your original tires will indicate if the recommended pressure for their aftermarket tires work best at a different pressure, but maybe not...then it is up to you. This topic has been discussed many times by using different methods such as chalking the tire tread and varying the pressure for footprint and ride quality.

Best,
Phil Schilke
Ranger Vehicle Engineering
Ford Motor Co. Retired

 

[slowmachine]

Hi Mike,

A back story.... Our CEO at the time, the ego driven Jaques Nassar, got into a firefight with the CEO of Firestone over the Wilderness AT tire on the Explorer due tire failure, resulting in tire blowout and sever accidents. Firestone CEO, Lampe, claimed the Explorer was poorly designed...Nassar claimed the tire was at fault, so the first edict from Nassar was to eleminate the Firestone Wilderness AT from all Ford Vehicles...Guess what...100% of Ranger 4x4a were on this tire. We headed to purchasing to see who in the tire manufacturers could support Ranger...then before we could make the decision, a further edict was to eliminate Firestone tires from all Ford production and to create a recommended list of other manufacturer tires for people driving vehicles that were still on OEM shipped Firestone tires. This created two problems. How to support production of new Rangers at a volume of 340,000 units a year times 4 tires per vehicle...and how to create a list of Ford certified replacement tires for a huge volume of vehicles on the road. Okay...the production support is detailed in another thread, but here is my point for the after sales replacement of Firestone tires.

My vehicle dynamics engineers had to certify by testing each tire for this list of replacement tires. This was a major headache with the volume of testing needed, but slowly but surely we chipped away at the tires of the sizes for Ranger 4x2 and 4x4. As part of the testing, the engineers had to determine the tire pressure for the specific tire, brand and design. The pressures were all over the map. 30 psi, 32 psi, 40 psi etc. The matrix of the tires grew to over some 40 different tires. Thus it became impossible to incorporate all these tires into the owners manual.

So the take away is your postulation of purchasing OEM wheels in another diameter for the tires of your choice is very rare. If you choose this route, the Ford Dealer is your guide to the tire pressure you need if the tire manufacturer does not have a recommendation. For such a scenario, your door label many or may not be correct as you modified your vehicle from as built. Tire Manufacturer of tires of the same size as your original tires will indicate if the recommended pressure for their aftermarket tires work best at a different pressure, but maybe not...then it is up to you. This topic has been discussed many times by using different methods such as chalking the tire tread and varying the pressure for footprint and ride quality.

Best,
Phil Schilke
Ranger Vehicle Engineering
Ford Motor Co. Retired

Thank you, Phil. As stubborn as I sometimes am, I’m learning something here. From what you’re saying, I can see that there may be more variation between these similar tires than I previously thought. Lacking the controlled conditions that you would use for OEM validation, I‘ll have to pay a little bit of attention to tire temperature and tread wear to fine tune the pressure settings for my alternate-brand tires. On to the next thing...

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