33x12.5 on 15x10 rim - backspacing, offset question | Ford Explorer Forums - Serious Explorations

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33x12.5 on 15x10 rim - backspacing, offset question

King$nake

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City, State
Oceanside, CA
Year, Model & Trim Level
1998 Eddie Bauer 5.0
Well since I haven't found the right tire+rim package for sale yet, I think I may be buying some 33x12.5 BFG AT's or MT tires, and purchasing the 15x10 rims separately, probably off of summitracing.com.

The lift is a 3" spindle, TT & Shackles. 2WD explorer 4 door

What kind of backspacing do I need in the rims for this combo? What should the offset be? Would like some negative offset but I do not know what limits are
 



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going to watch this one as i may be going to the same combo. i've seen a few guys post 3.75" backspacing...

i don't know about offset
 






15x7 with 0 offset of 15x8 with -19 offset. If you go with too wide of a wheel it throws you KPI (king pin inclination) way off and worsens the ride quality followed by parts prematurely wearing out.
 






Dan,
i'd like to go with a 17" rim. the Cragar soft 8's only come in 8 or 9 inch widths. i think i want to go with an 8" wide. the offset option for both is 0.00.
the 8" has a 4.75" backspacing
the 9" has a 5.00" backspacing

i'm planning on running a 255/75/17 tire, which said the rim widths are 6.5 - 8.5

i'm totally lost on what rim i should buy. would that 0.00 offset be ok?
 






I may be speaking incorrectly here but I'm fairly certain that factory offset is 00.

You will want at least 3.75 backspacing (or less). The smaller the backspace number the further out the tire rests.

You still may not be able to clear 33x12.5 with only 3.75BS and 00 offset because that wide of a tire may rub the radius arm at full lock.

BFG sells their A/T in a 32x11.5 size. This would be my recommendation for you and then just get the Cragar soft 8 with the 3.75BS and 0 offset and you should be good to go.
 






I may be speaking incorrectly here but I'm fairly certain that factory offset is 00.

You will want at least 3.75 backspacing (or less). The smaller the backspace number the further out the tire rests.

You still may not be able to clear 33x12.5 with only 3.75BS and 00 offset because that wide of a tire may rub the radius arm at full lock.

BFG sells their A/T in a 32x11.5 size. This would be my recommendation for you and then just get the Cragar soft 8 with the 3.75BS and 0 offset and you should be good to go.
They don't make the wheel with 3.75 backspacing. It's 4 or bigger. So I believe you'll need wheel spacers to run them. I have 15x8 4.00 and -19 offset (I think) and the inside of the wheel is in the same spot as factory. I don't quite know how that worked but it did. I'm throwing on some 33x12.5's m/t's next weekend so we'll see what happens. Either I'm gonna be trimming a bunch of stuff or getting spacers, but I know their gonna rub :(

Also kinsnake there is a good thread in the wheel and tires section that explains how it all works, plus there is a little calculator thing that'll tell you how your wheel will sit differently with different offsets and stuff, kinda neat I'd check it out. Anyways keep my posted because you and I are in the same boat :)
 






15x7 with 0 offset of 15x8 with -19 offset. If you go with too wide of a wheel it throws you KPI (king pin inclination) way off and worsens the ride quality followed by parts prematurely wearing out.

By the way good point.

When you increase the turning radius (wider wheels) you change the king pin angle, which not only causes a harsher ride, but also with put more wear and tear on your components, however it will be easier to turn the wheel :P
 






I ordered my 4 rims today, some Pro Comp xtreme rock crawler 152 in flat black. Went 15x8 per danwaters advice, with a -19 offset:

8d957ad303e50690d671a7a43b23.jpg


Once I get the rims I am going to take them to discount tire and have the General Red Letter 33x12.50's put on. By that time I should have my shocks and spindles installed, which are currently sitting in the garage. Gonna be a fun next couple of weeks.

The tires+rim combo should look much like this:

GeneralGrabber.jpg
 


















I might have a good deal on a set of 15x10 wheels with 4" backspace and a set of 33x12,5 MT tires.. will it fit my first gen?
 






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