What Info is Needed to Pick Out Correct Offset 17.5 inch Wheel

Updated 12/17/2024 | Published 12/12/2024

Question:

I’m looking to match my existing rims on my cattle trailer. 17.5 mod rim. I’m measuring with the rim on the ground. 4 1/2” from the ground to the hub side of the rim. What offset matches that measurement?

asked by: Tanner L

Expert Reply:

What is the width of the wheel? In order to determine what offset you have I would need to know the current width so I can see what your 4.5 inch dimension indicates. A zero offset means the hub face dimension is perfectly centered so I would need you to take the width of your wheel and compare it to the dimension you took to know what offset you have. Most trailer wheels have a zero offset or very close.

expert reply by: Jameson C

Tanner L.

12/12/2024

The rim width is 6.75

Jameson C.

12/12/2024

@TannerL You have nearly a 2 inch offset. Does the hub mounting surface seem very off from being centered? We don't have any offset wheels with that much of an offset. If you had a zero offset it should have been 2.875 inch that you measured.

Tanner L.

12/16/2024

@JamesonC the rim measures 8.5” when laying down on the concrete to the tallest lip on the rim.

Jameson C.

12/16/2024

@TannerL Okay so to determine backspacing using the numbers you've given it sounds like you have a positive offset of 1/4 inch. To determine this I took your overall width figure of 8.5 inch, subtracted 1 inch for the mounting lips on either side of the wheel and divided by two. A zero offset then would be 3.75 inch. Since the number you measured earlier was 4.5 inch that means you'd remove 1/2 inch from that for mounting lip and then compare to 3.75 inch. So 1/4 inch positive offset. So closest option we have is a .19 inch offset like with the black part # AM85NR or the gray part # AM75NR.