OK so now that we have that squared away, when ordering from 4wheelparts do you go off of the backspacing or the offset and which ones are correct. I'd like the 5.1 backspacing if they make those.

 

Well, they're both correct for a given wheel and both numbers give you the exact same information. A wheel with a certain amount of backspacing is going to automatically have a coorelating amout of offset. For example....you would never have a wheel with 5" of backspacing but then have the option of -12mm offset or -25mm offset. (just to make up some numbers to show a point). A wheel of a given size is going to have an offset that matches the backspacing. i.e. a 20X10 (or any 10" wide wheel for that matter) with 5" backspacing is always going to have -12mm offset. Both numbers tell the exact same story.

When ordering, it simply comes down to what number is easiest for you to understand and that's it. No other math or confusing issues to worry about. Just pick one.

Most people understand and use backspacing as it's easier to visualize how it will fit on the truck...if you have a previous reference to go by...i.e. you knew the backspacing on your current wheels for comparison.

Understanding offset comes in handy when a wheel manufacturer or store does not advertise backspacing but does advertise offset only. Then it's simply a matter of doing the math (or using that nifty chart) to figure backspaing for the visual effect.

 

Galaxy, I completely understand backspacing and offset, I was just stating that if you go to 4wheelparts websight and look up the 951's(these links have been posted on this thread) The offsets and backspacing DO NOT MATCH UP. I don't want to order the rims with 5.1" of backspacing and get the rims with 30mm of offset. Get what I'm sayin.

http://www.4wheelparts.com/PDT244675.aspx
http://www.4wheelparts.com/PDT244674.aspx

 

Ahhhhh...got ya!! Looking at those two wheels, the one with 18mm/5.71 is correct. The other one is an error on the description. You should give them a call and see which number is corect, the 30mm or 5.1" BS. I would be willing to bet good money that wheel has the 5.1" BS and the 30mm offset is the type-o.

 

I thought the same thing untill others posted pics of MM with 30mm offset. I should give them a jingle.

 

Awesome Chart!! And when measuring the backspacing, do you use the outside or the inside as your reference point to take your measurement??

 

So I called 4wheelparts and talked to a Mat. Anyways after 5 min. of arguing with him, he gave me MM # and told me to talk to them. HE was saying that the offset had nothing to do with the backspacing and that it does have 5.17 backspacing and 30mm of offset and He guarantees it will have about a 4 inch lip. So I call MM and they tell me they make a -12,18,and 30mm offset wheel in the 18X9. They don't even make a 18X9 wheel with 5.17 backspacing. I then called 4wheelparts back and tried to explain this to them. I told them they need to update there site because there numbers are wrong. They told me that this 5.17" backspacing rim with 30 mm offset is a new rim that they might make so they don't want to remove it from there site.

Now what rim!

 

HA!! Friggin 4wheelparts...did you read this one?? Read my post in here too!

https://www.f150online.com/forums/sh...d.php?t=302676

 

yeah won't be buying from them

 

IF they were compitent...which my experiences show otherwise...their prices are waaaay to high on most stuff. I've found good prices on shock specials and some other things from time to time but as a general rule, not so much!

I will give them the benefit of the doubt though, as I don't know about the guys working in the back. My statement referrs to everyone at the counter I've ever dealt with. I spoke with the guy at my local one that does alignments and he seemed to be straight and narrow! Great guy.

 

only delt with them over the phone.