I also posted this in the frequently asked questions under Frenchy read this first thread, I got tired of trying to find on the internet what my back space and offset is for my stock wheels so I pulled one just measured it myself..

Watch these videos..

http://www.monkeysee.com/play/14464-...eels-and-tires



Well since I could not find the back spacing or offset for my stock 18x8 wheels I pulled the tire off and measured myself just to be sure so when I go shopping for my after market wheels and these are the numbers I got..

0921091306_0001_0001.jpg

To start these wheels that the manufacture lists at 18x8 is wrong it measures 18x9

this will help you determine what kind of wheel to buy and what kind of tire you can run on your new wheels..

bolt pattern which all wheel manufactures list for our trucks is 5x5.5 which is 5 lug by 5 1/2" or 5.50 or 5x139.7 millimeters I measured on my wheels 5 3/4" or 5.75

Back spacing on these wheels are 5 1/4" or 5.25"

offset for these wheels are positive offset of 1 3/8 to 1 1/2 or right around 37 millimeters

what seems to be the norm the more the the after market wheel gets closer to the centerline of the rim or 0 offset or in the negative offset, it reduces the tire size you can run because of it pushing the tire out away from the truck and then run into rubbing issues..


Here is where it shows you how to measure your wheel if you feel the need..

https://www.rsracing.com/tech-wheel.html

Update I just found out what our stock offset is and that would be +38 I was only Millimeter off LOL

 

Update I just found out what our stock offset is on a wheel website and that would be +38 I was only Millimeter off LOL

 

You double posted the same thing you added in the edit FYI... but thanks that is really helpful to us lazy people planning to buy new wheels soon!

 

Now I am going to be talking to people on here that bought after market wheels and see what there offset was so they could still run there same tire that came on there truck or bigger.. The thing that drives me crazy is the manufacturer put such high offset wheels on these trucks??????????? what for, could have made it 0 why a +38 well I will post my results since it seems that this has not been covered very well in this forum.. Cya Slick

 

Slick, how did you determine that the wheels are "actually" 18x9? You mentioned that you "pulled the tire off" to measure. Did you remove the wheel and measure, or did you dismount the tire and measure from the inside bead-seat to outside bead-seat?

 

Good question, I was thinking the same thing. I also disagree with his statement on his bolt pattern being 5.75"

His measurements are off consistent that he measured to the outside edges on the wheels(not the seats) and the outsides of the of the studs which is not even how the link he posted shows.

I will be measuring my bolt pattern this evening for fun, going by the link he posted and see what I come up with. A quick measurement earlier was consistent with 5.5"

 

Here is how I measured it, but we all know that it goes by

tech-boltcircle.gif

I did the math between the back space and the offset numbers since I new those measurements I took where dead on.. So when you do the math the numbers don't lie, it's a 18x8 wheel, not 18x9 my mistake thanks for catching it.. I figured that would be the best way to figure the wheel width because once you add them all up it can only be what it is and 18'x8.. Not to long now for my new wheels to show up, I got it narrowed down to three wheels..

Cya Slick

 

Yeah I measured the bolt pattern last night using the what you have posted there and it is 5.5".

 

yup 5.5!!


Now for the Offset, if +38 is stock, what # will I need to move the rim mabye an inch or so farther out? for a little wider stance,

Right now I'm running stock 17"x8.5" Rims, with 265/65/17 Tires

 

Here is my thing you have to watch when buying your wheels, if they have a sunkin in type look that you like to the wheel, if your offset is two much like +38 like the stock wheels you will change the look of the whole wheel all together.. Anything less then +38mm offset will bring your wheel out from the truck and since there is 25.4mm in a inch you do the math to how much your wheel will stick out..

I myself am shooting for some thing in the range of "0" offset to as much as +38 depending on what the look of the wheel is supposed to be, I suggest you get to see the wheel with a positive offset first before buying it.. I have looked high and low and I am not seen a wheel that has jumped out and said buy me, because eighter the bolt pattern is not right or the offset is in the negative range and we know from reading from what other guys on here have said.. That a negative -12 will not run with out major rubbing unless you want to drop the width of your tire to a 245 or less /65/17 "NOT ME" I like wide..

I hope that helps.. Cya Slick