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Discussion Starter #1 (Edited)
Ever wonder what the difference in spacing of an aftermarket wheel will be on your truck? Me too, so today I made an Excel spreadsheet (triple) calculator to compare wheel sizes. I think this will help people answer a few lingering questions...

1. What size tires are these? (tire size calculator)
2. Whats the size difference between these offsets? (offset calculator)
3. How far will a new wheel stick out beyond the stock one using the hub mounting surface as a reference point (in inches)?. (difference calculator)

Feel free to download, use, edit, change, break, or upgrade this if you think it will help you because you have similar questions. Also, please feel free to check my work on the formulas.

A few notes:
1. you really only need to input values in the green boxes.
2. please read the comments (little red corners) in the cells for clear explanations of how it all works.
3. Support is limited...:p

There is a link floating around the forums that takes you to a website that does this and more, but this approach is for people who want to know what is going on in the background... How the calcs are setup.

Here's the [corrected] link do the download: Aj3's Wheels Spec Download - Mediafire
Here are the screen shots:



 

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this would help but it wont let me download :( am looking at the xd monsters 20 inch are 22 inch with the 18 off set. i dont want the tire to pass the fender flare any if i can do that i would like the tire an wheel to be even with the fender flare. maybe if someone who can get the down load to work maybe help me help. thanks jason
 

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Discussion Starter #5
this would help but it wont let me download :( am looking at the xd monsters 20 inch are 22 inch with the 18 off set. i dont want the tire to pass the fender flare any if i can do that i would like the tire an wheel to be even with the fender flare. maybe if someone who can get the down load to work maybe help me help. thanks jason
Still works fine for me. Tested it as a guest from a different system. Maybe check your internet permissions/security?
Anyone else?

If you still can't get it downloaded, let me know of the wheel/tire sizes you were considering and I'll crunch the numbers for you.
 

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we need to link this to the offset pic thread that is here too...
 

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this would help but it wont let me download :( am looking at the xd monsters 20 inch are 22 inch with the 18 off set. i dont want the tire to pass the fender flare any if i can do that i would like the tire an wheel to be even with the fender flare. maybe if someone who can get the down load to work maybe help me help. thanks jason
a +18 will be past the fender.

stock +60, close...

rw wheels with a 285/70r17 are 1/4 to 1/8 in at most, so put 1 inch outside more and there you have it, that is with a 285... go to a 305 and the fact that all aftermarket wheels are wider and you are more lie 1.5ish out...

I ran into this issue myself.
 

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and you need current excel to use.
 

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I would really like to know the actual difference between my rw wheels and the +30 and +18 wheels with a 33x12.5 tire... 18 x9 wheel too...
I need to get my excel to work fist tho.
 

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Still works fine for me. Tested it as a guest from a different system. Maybe check your internet permissions/security?
Anyone else?

If you still can't get it downloaded, let me know of the wheel/tire sizes you were considering and I'll crunch the numbers for you.
i tryed again from the g/f's laptop an no go :confused:
i was goin to go with the 20 inch monster wheels with the +18 offset are the other offsets i can get is +35 an a -12 offset .. i dont want to much to pass the fender flare. the tire i was going to go with is the toyo open county since thats what most of u guys are running on here. 35x12.50r20 i think the tire is also a 325/60r20. i was looking at going with a bigger rim size the 22 inch but wow what a price tag on them an the rubbers :eek: so i think ill stick with the
20's lol thanks for the number crunch the fender flares bushwacker pocket ones mmm i think they add 2 inch i belive. jason;)
 

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This is really good stuff but I have a question. Under the "aftermarket specs" it shows a 12mm offset. How can there be an offset that is neither pos nor neg? If the offset is 12 shouldn't the backspacing be 5.472 and the frontspacing be 4.528? This would give you a difference of 2.388. Still a big difference just not quite as big. If it is a -12 then wouldn't you have what is shown on the chart? :confused:

 

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Discussion Starter #12
This is really good stuff but I have a question. Under the "aftermarket specs" it shows a 12mm offset. How can there be an offset that is neither pos nor neg? If the offset is 12 shouldn't the backspacing be 5.472 and the frontspacing be 4.528? This would give you a difference of 2.388. Still a big difference just not quite as big. If it is a -12 then wouldn't you have what is shown on the chart? :confused:
Good eye...allow me to explain.

The number shown is technically "+12" ...but...
The number actually used in the calculation is theoretically "-12" for the following reasons...

If the offset is positive you ADD it to the backspacing.
If the offset is negative you SUBTRACT it from the backspacing.

I had to use absolute value due to the capabilities of MS Excel. I tried using (displaying) a negative number but the calculation did not work out correctly. It just so happens that the right calculation (for a negative) offset corrects this. Hence, In the comments of the Excel spread sheet I state, "Offset is assumed to be negative). I decided to do it that way because most people are looking for wheels with a negative offset anyway.

Does this explanation help?
 

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Discussion Starter #13
i tryed again from the g/f's laptop an no go :confused:
i was goin to go with the 20 inch monster wheels with the +18 offset are the other offsets i can get is +35 an a -12 offset .. i dont want to much to pass the fender flare. the tire i was going to go with is the toyo open county since thats what most of u guys are running on here. 35x12.50r20 i think the tire is also a 325/60r20. i was looking at going with a bigger rim size the 22 inch but wow what a price tag on them an the rubbers :eek: so i think ill stick with the
20's lol thanks for the number crunch the fender flares bushwacker pocket ones mmm i think they add 2 inch i belive. jason;)
Sorry you can't get the download. Its working fine for me from a few different computers. Maybe check your DL perms?

Here are your numbers...
325x60/R20 = 35.354 inch tire.

mm to inches sidewall height
12.795 wide 7.677

For the XD Monsters, I'm assuming they are 20x10's
Aftermarket Spec: The magic number you are looking for is 4.79"
These wheels will stick out that far from the mounting surface. Keep in mind the tires will bulge a little over the wheels.

To compare this number to stock, I would have to know your stock wheel dimensions... Diameter and width.
 

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Discussion Starter #14
this would help but it wont let me download :( am looking at the xd monsters 20 inch are 22 inch with the 18 off set. i dont want the tire to pass the fender flare any if i can do that i would like the tire an wheel to be even with the fender flare. maybe if someone who can get the down load to work maybe help me help. thanks jason
Changed the link and validated my account... please try it now.

This is really good stuff but I have a question. Under the "aftermarket specs" it shows a 12mm offset. How can there be an offset that is neither pos nor neg? If the offset is 12 shouldn't the backspacing be 5.472 and the frontspacing be 4.528? This would give you a difference of 2.388. Still a big difference just not quite as big. If it is a -12 then wouldn't you have what is shown on the chart? :confused:
Added an additional table for positive offset wheels for ease of use.
 

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Sorry you can't get the download. Its working fine for me from a few different computers. Maybe check your DL perms?

Here are your numbers...
325x60/R20 = 35.354 inch tire.

mm to inches sidewall height
12.795 wide 7.677

For the XD Monsters, I'm assuming they are 20x10's
Aftermarket Spec: The magic number you are looking for is 4.79"
These wheels will stick out that far from the mounting surface. Keep in mind the tires will bulge a little over the wheels.

To compare this number to stock, I would have to know your stock wheel dimensions... Diameter and width.
thanks bro i get my fender flares this Friday so ill measure for the magic number. how do i back down 4.79 to the offset that all the wheel company's going with now. am old school i do it in the inchs lol i have no idea on the new offset numbers like +18 an the other ones i said earlyer.
 

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Great Link

This is a great link you devised. If I'm using it properly, I think a set of XD, in 18" (which have 0 offset) and 9" wide will protrude out an additional 2.86" from my stock 18s. I have a 3/1 level/lift in progress right now. Will 305/65R18s on the XDs give me any issues? I can live with slight tweaking of skid plat if needed. Thanks for the input. I'm brand new here and am trying to find my way around.
 

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Discussion Starter #19
@Paycheck, is your truck a 2nd Gen? If so, I'm pretty sure that you'll have to trim your skidplate, and either remove the front well housing or push it back. Check around here for some write ups on that.
 

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That's ok. I'm returning the lift for now. I saw a good deal on a new 2016 DC Limited 4x4 last night and I traded the '13 for it.
I feel much better now!
 
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