Local shop arguing with me. Input Please!

So I bought my lift and 285/70/17 toyo open country AT2's.
The rims are ION 171 all black 17x9

I feel confident when I say 0 offset is gonna be 5.00 backspacing.
I told them that was wrong and I need -12 offset to gain the correct 4.5 backspacing I "believe" I'm going to NEED with this 3" lift and 285's.

They went back and forth with me over and over and their logic "9 wheel zero offset split 9" in halph you get 4.5 makes sense to me yes BUT!

All the offset to backspacing calculators I can find all say the same and that's that you need -12 offset on a 9" wheel to achieve 4.5 backspacing not to mention the online sites selling wheels stating 17x9" wheel with -12 offset and 4.5 backspacing.

Am I, the countless other places selling wheels and the crazy number of guys running this setup correct "OR" is this local shop?

I haven't taken these wheels and tires yet. I want to be 100% sure first.

 

They are forgetting (or don't know) how "wheel widths" are measured. A 9" wheel is actually 10" wide. The 9" refers to the width between the beads, you add about 1/2" per side to get the actual width edge to edge.

With a 0 offset 9" wheel, you have 4.5" from the mounting flange to the BEAD EDGE, which is about 1/2" short of the WHEEL EDGE. So a 0 Offset 9" wheel has 5" approximately of backspacing. 12mm is 0.47", so with a -12mm offset wheel, you get 4.5" to bead edge + 0.5" bead edge to wheel edge - 0.47" offset correction = 4.53" backspacing.

Which is exactly what you get with the various online offset/backspace calculators.

If your shop continues argue with you, have them grab a 9" wheel from inventory and put a measuring tape to it....

But you are right, they are wrong.

 

Great explination! Now in the very short time it took me to read this I have a better understanding of wheel offset and backspacing then the guys who do it there everyday.

Make me feel real safe buying from them. I will be sure to put this new knowledge to use, hopefully I don't piss them off too bad but hey it's my money, not theirs.

Thanks again.

 

Here's an update, lift went in tonight wheels DOnT FIT! I told those guys twice and all 8 of them told me I was wrong and promised they would fit. Well.... They don't even clear the calipers. Aluminum on caliper rubbing is not what I paid all that money for. Very pissy now and now I gotta sleep on it all night before I can go back.

 

ive never heard of 17's hitting the caliper

 

Did they forget that the customer is always right?

 

They are hitting the outer side of the caliper, so where the spokes roll out from the mounting flange there isn't enough clearance.

 

Yeah, I have 17x9 methods on and they clear the calipers just fine.

 

Look into Mickey Thompson for that wheel style.

 

It's the wheel design and not the size thats the issue. What's known as the X-factor is where the problem is.

 

Yeah, definitely cuz of the back spacing. 4.5" wouldn't do that.

 

Well this shop is pretty big in the New England Area they are called
Town fair tire. The perks of buying from them is what brought me in, I just figured for a company so large and who claims to have wheel and tire experts that they would have seen this coming.

Guess I'm one of the unlucky ones.

 

What a nightmare.

The minimum offset I'd run on a 17x9 (for any rim) would be a -6. Anything else is going to rub somewhere. Are they doing anything to help you resolve the issue?

 

Sounds like they need to switch your wheels on their dime. You tried to tell them, but they insisted these would fit. They don't, their wrong they fix.

 

I hear ya, but give them a chance to make it right. Sometimes it's difficult to be 100% correct all the time. They probably deal with a bunch of different wheel companies and work with all types of makes and models. That type of wheel design is hit or miss even when they think the BS is correct.

 

it must be just that shop as I bought my tires off town fair, and they mounted the tires and rims on my truck without any problem...

I run 285 75 R16 with some Dick Cepek DC2s... Since it's a 16 inch rim I didn't want to chime in on the 17 inch rim prob.. sorry.