How to Calculate Tire Max offset?

[GriffinH]

I have a Big Bend Bronco getting raised 2 inches (RC Lift) I currently have 285/70/R17 Winter tires, and have just ordered 17x9 Rims with a -15mm offset.

How can I make sure these rims will fit? Or does anyone have an offset rim ratio like this?

Thanks in advance

Sponsored

 

[Cetacean Sensation]

https://www.1010tires.com/Tools/Wheel-Offset-Calculator

 

[SS Bronco]

They will fit, they will just poke out pass your flares. Check out the wheel and tire thread . There are 1000’s of post, good chance someone posted pictures of a similar set up.

 

[SasquatchMansquatch]

They'll be outside your fender flares just a bit. Just an FYI, but they should fit.

 

[RhodeIslandRed]

That is a ton of negative offset. They are going to poke a ton. +55-(-15) will be 70mm or 2.75". You are also going to get some from jumping up in wheel width.

This might be a more complicated calculation because of the offset, but you can estimate half of the increase in wheel width for additional poke. According to another thread, the stock non-sas big bend has 7.5" wheels. So that would be 0.75" more poke just from the wider wheels.

So going from 7.5 +55 to 9 -15 will net you something like 3.5" of additional poke.

I know you are probably asking about clearance. You will have plenty of clearance.

 

[ATLBronco75]

This is my favorite calculator because it updates the image and shows you the actual change of the outer edge and the hub.

https://tiresize.com/wheel-offset-calculator/

 

[Bruno]

2 Questions come to mind:

1) What is the offset of the existing stock rims: Steel, Sas, etc.
2) What is the distance from the rotor hub face, to : Body outside surface, Small flare outside edge, Large flare outside edge.

I wish someone did a diagram calling out all these dimensions.
It would really take alot of guess work out for people.

 

[RhodeIslandRed]

This is my favorite calculator because it updates the image and shows you the actual change of the outer edge and the hub.

https://tiresize.com/wheel-offset-calculator/

That is the best one I've seen. Thanks for sharing. Wish I had that link a year ago.

A few notes for anyone that stumbles onto this.

YMMV
This doesn't account for wheel width and that can cause your tires to balloon out or ride narrow. It's probably impossible to illustrate that accurately with so many other variables. But just beware.

This also shows you a straight-on view. But remember that it is when your steering is at full lock that you are going to get contact. So while you might be further away from the front end when the wheel is straight, with a bigger radius tire, you might make contact with stuff fore and aft when turning.

But this definitely gives you some idea. I love it.

This is my exact before an after spec and it's probably pretty accurate, but I jumped up in wheel width. And I also did the spacer level lift in the front so I haven't had any rubbing issues.

Sponsored