Ford rims have 15x7x12 stamped on them. What exactly is the 12?

[outatime88]

So I went to the junkyard today and found some of the teardrop ranger/explorer rims and decided to buy five of them even though I wanted to continue using my 14s.

Two of them say F67A 1007-NA and 15x7x12
Three of them say F87A-1007-SA and 15x7x12.0

So what does the 12 in 15x7x12 indicate?

Between these wheels I notice that the structure of the rim is different, the F67A wheels have sort of a step up half way through the rim and the F87A have a tapered style. I need to get a scale but I think I noticed they have a slight difference in weight.

Also what are the chances that these all have the same offset and will they all fit 2wd?

 

[85_Ranger4x4]

I think rangers always had the same offset.

 

[97RangerXLT]

Just a wild guess here... but could the 12 be the maximum diameter of the brake rotor/ drums that the rim will clear?

AJ

 

[pjtoledo]

12 is the offset in millimeters. for reference 12.7 mm = 1/2"
those wheels all have a 1/2" offset.

 

[85_Ranger4x4]

12 is the offset in millimeters. for reference 12.7 mm = 1/2"
those wheels all have a 1/2" offset.

Rangers also have 1/2" diameter wheel studs.

 

[outatime88]

12 is the offset in millimeters. for reference 12.7 mm = 1/2"
those wheels all have a 1/2" offset.

But why would Ford use two different dimensional units and not even show a physical representation to know which is IPS and which is metric? Seems like poor engineering practice to me

 

[pjtoledo]

don't blame Ford, it's an industry standard (in the U.S.) to define wheel diameter & width in inches, offset in millimeters. backspace is usually inches, bolt circle diameter can be either.
it's one of those "Oh, we thought you knew what we meant" situations

 

[sgtsandman]

Yep, that is industry wide. Not just Ford. It can make it confusing when looking to get new or replacement rims. Especially since some rims are listed with offset and others with backspacing.

 

[outatime88]

don't blame Ford, it's an industry standard (in the U.S.) to define wheel diameter & width in inches, offset in millimeters. backspace is usually inches, bolt circle diameter can be either.
it's one of those "Oh, we thought you knew what we meant" situations

Yep, that is industry wide. Not just Ford. It can make it confusing when looking to get new or replacement rims. Especially since some rims are listed with offset and others with backspacing.

Interesting, well I guess its good that I don't have to measure the offset since its already stated.

So here's another question for you guys, as you can see in the photo these two wheels have a different structure, the one on the left has a step and seems to weigh slightly more than the tapered rim on the right. Is there anything wrong with using both rims together?

If the rims do in fact weigh differently (I'm going to get a scale), I should only run the ones that are heavier on the rear(left and right), and the lighter on the front(left and right)? I would think running different weighted rims on one axle would be dangerous.

 

[sgtsandman]

You’ve gone farther into the rabbit hole than I have. Spare tires on vehicles often have different rims and tires than the rest of the vehicle but are not meant for long term use.

I can’t see where your thinking is faulty. But someone else might be able to give you a more knowledgeable answer.

 

[85_Ranger4x4]

Running a full-size spare on a steel rim with three alloys I never noticed a difference.

 

[4x4junkie]

I don't think this is something that will matter.

But if you're worried about it, then run two of the same on the front, and the other same two on the rear (which ones go where does not matter, and won't play into a normal 4-tire rotation at all).

FWIW, the unsprung weights on the front axles of these trucks ('83-'97) are already not the same on both sides to begin with (especially on 4WD models) due to the design of the front axle beams.

 

[pjtoledo]

Interesting, well I guess its good that I don't have to measure the offset since its already stated.

So here's another question for you guys, as you can see in the photo these two wheels have a different structure, the one on the left has a step and seems to weigh slightly more than the tapered rim on the right. Is there anything wrong with using both rims together?

If the rims do in fact weigh differently (I'm going to get a scale), I should only run the ones that are heavier on the rear(left and right), and the lighter on the front(left and right)? I would think running different weighted rims on one axle would be dangerous.

View attachment 29679

the wheel on the left, stepped one, has clearance for a larger 12" front brake rotor.
the tapered one is for 11.25" front rotors.
since you have a 1997 the rotor upgrade is not do-able, so the wheel differences are a non-issue.

 

[outatime88]

the wheel on the left, stepped one, has clearance for a larger 12" front brake rotor.
the tapered one is for 11.25" front rotors.
since you have a 1997 the rotor upgrade is not do-able, so the wheel differences are a non-issue.

Ah I see, I had a feeling it had more of a specific reason.

Thank you for the help guys, I'm going to make a trip to another local junkyard and see if I can find any more matching rims and if I can't find anything to satisfy my OCD habit of having everything be the same then I'll just do the two of one type in the front on the other in the back.