Wheel question?

[WV_Outdoorsman]

Hey guy's I finally ordered my bumper/tire rack and I also ordered a new rim and tire for the YJ. Now let me tell you my concerns and you guy's tell me if I should be or not. My jeep came with American Racing Baja rims with 33's mounted. Everyone I have talked to has told me that they have to be on a a ten inch rim. Well the wheels look to me like they are at least ten inches wide because the tires and wheels stick out at least four inches past the fender flares. So now I'm reading about back spacing.
When I ordered the rim back spacing wasn't even a question it's just what size and make of vehicle so I ordered a 15x10 and a 33x12.50 tire. Do you guy's think it could be different size with the backspacing thrown in there? I'm thinking maybe I should call them and tell them not to mount the tire, when it comes in pick the wheel up and bring it home and check it. I don't want one wheel that's different than the other four. Does anyone know how I can measure the wheel I have with them mounted on the jeep and with the tire mounted on the rim as well?

Thanks,
WVO

[HillBillE]

Hey WVO, a 33x12.5 doesn't need to be on a 10'', an 8'' is fine, and actually works better for airing down, IMO.

Any way, having the same backspacing on all your wheels is important. If you ordered another American Racing wheel, you should be good, unless the ones on your Jeep were special ordered. I bought 3 used American Racing wheels (15x8), I ordered another to have a full set, and backspacing didn't come up either, but the wheel was the same as the others. (4")

Here is a sticky from the 4WDH forums, good info on wheels.


Taken from the 4WDH forum:
ok, so i'm a bit of a grumpy old (lower middle aged?) fawk the last couple days. maybe i'm always like that, who knows. but i've been seeing question after question about backspacing and people say there are no answers to their search results that help. here's the end all to cure all.

How to Measure Bolt Patterns
http://i3.photobucket.com/albums/y87/craigparrish/Backspacing/tech-boltcircle.gif


How to Measure Wheel BackSpace
http://i3.photobucket.com/albums/y87/craigparrish/Backspacing/tech-backspace.gif
The easiest way to measure backspace is to lay the wheel face down onto the ground so the backside of the wheel is facing up. Take a straight edge and lay it diagonally across the inboard flange of the wheel. Take a tape measure and measure the distance from where the straight edge contacts the inboard flange to the hub mounting pad of the wheel. This measurement is backspace. The above photo shows three wheels with 2",3", & 4" backspace.


Measuring Wheel Offset
http://i3.photobucket.com/albums/y87/craigparrish/Backspacing/tech-wheelfit1.gif
To calculate offset you'll need the following measurements:
Wheel backspace
Wheel Width
Wheel Center line (outboard flange to inboard flange measurement / 2)
Subtract:
Wheel center line from Wheel backspace to get offset.
If backspace is less than the wheel centerline the offset is negative
If backspace is greater than the wheel centerline the offset is positive
Tip:
To convert from inches to mm multiply by 25.4
To convert from mm to inches divide by 25.4


Backspace to Offset Conversion Chart
http://i3.photobucket.com/albums/y87/craigparrish/Backspacing/tech-wheeloffset.gif


Determining Vehicle Fitment
Fitting a wheel and tire package is different for each vehicle, but by following these guidelines your chances for success will be much greater. In most cases you'll have to use the physical dimensions of the current wheel/tire package to determine the dimensions of the new wheel/tire package.

Items which are potential trouble spots:
Tie Rod Ends
A-arms
Brake Calipers
Shocks and Shock Mounts
Inner & Outer Fenders (esp. front tires turned to lock)
http://i3.photobucket.com/albums/y87/craigparrish/Backspacing/tech-wheelfit.gif
In the drawing above, we've made two measurements
Front Side Clearance
Back Side Clearance

These measurements when used with:
Tire Section Width
Tire Diameter
Rim Width
Rim Backspace

Help determine if wheel/tire clearance is adequate for the new wheel/tire package you've selected

Suggestion: Start your search for new wheels by picking the tires first. Get the tire manufacturer's rim width recommendations and physical dimensions for the tires you want. Pay close attention to Section Width and Measured Rims specs., these are important numbers to be used when selecting rims and determining vehicle fitment.


Determine Wheel Caliper Clearance
http://i3.photobucket.com/albums/y87/craigparrish/Backspacing/tech-wheelfit2.gif
A. Caliper Overhang Distance
Used to determine if wheel dish is adequate (in some cases a spacer is required for clearance)
B. Diameter of Hub Center
Required if wheels are hub centric
C. Wheel Stud Diameter
Required along with bolt circle
D. Height of Hub Center
E. Length of Lug and Thread Type (Fine or Coarse)
Required to determine if longer studs are necessary
F. Distance from CL of Hub to Caliper
Used with A to determine if a spacer is required for proper fitment
G. Width of Caliper
Used with F to determine if wheel ID is adequate to clear rotor/caliper package
H. Diameter of Hub Mounting Face
Used to determine if hub is adequate to support wheel/spacer


Typical Lug Nut Torque Specifications
http://i3.photobucket.com/albums/y87/craigparrish/Backspacing/tech-lugtorque.gif
Lug Size........Ft/Lbs Torque
7/16"...............55-65
1/2".................75-85
9/16"...............95-115
5/8"................135-145
12mm...............72-80
14mm...............85-95


Wheel Terminology
http://i3.photobucket.com/albums/y87/craigparrish/Backspacing/tech-wheelterms.gif
Bolt pattern or lug pattern or bolt circle is determined by the number of bolt holes and the bolt circle diameter.

Hub Diameter or center bore is the hole at the center of the wheel.

Rear spacing or back spacing is the distance from the backside of the wheel mounting pad to the outside of the rim flange.

Offset The distance from the centerline of the wheel to the mounting surface of the wheel.

Negative offset When the back of the bolt pad is closer to the inside of the wheel; when mounting surface is inboard of the rim centerline.

Positive offset When the back of the bolt pad is closer to the street side of the wheel; when the mounting surface is outboard of the rim centerline.

Bead-Loc A device which captures the tire bead between it's flanges, usually secured by bolts to keep tire bead from dismounting.

[WV_Outdoorsman]

Thanks HillBillie I'll take some measurements tomorrow and see how it turns out. It's a bit difficult to get the proper measurements with them mounted on the jeep. I don't think an 8" wheel would stick out past the flares as far as these do.

Thanks again,
WVO

[HillBillE]

Thanks HillBillie I'll take some measurements tomorrow and see how it turns out. It's a bit difficult to get the proper measurements with them mounted on the jeep. I don't think an 8" wheel would stick out past the flares as far as these do.

Thanks again,
WVO

Probably not, not with the 'standard' 3.75 to 4'' BS. My tires only stuck out past the factory flares by 1/2" on front, and are covered by the flares on the rears. (with 8" wheels)

Good Luck! The American Racing wheels are really beefy (the steel ones), I like them alot.