Correct offset for 18x9??

BFE TITAN · 05-22-2007, 10:30 AM

Talked to Greg and will be ordering a cst 4" spindle lift with 2.5" spacers for the front and a 3" block in the rear for my 07 SE 2wd. I am torn between keeping my stock 18" wheels or getting an a/m set. If I go a/m they will be 18x8.5 or 9. If I do decide to go a/m what offsets should I be looking for? I dont mind if I have to do the pinch weld mod as long as thats all I need to do. I called discount tire and they werent much help at all. Any info?? Thanks.

BFE TITAN · 05-22-2007, 12:42 PM

I was looking at the Incubus Recoil wheel in a 18x8.5 with a 12mm offset. Think it will fit???

Spencer@tirerack · 05-22-2007, 01:59 PM

Offsets are a funny thing, and it is a rather common myth that there are specific approved offsets. This is logically, not true. ie. you can have two wheels, the exact same size and offsets, one someone can tell you that the specific offset will work. problem is, one of the wheels has a deep dish and this the spokes move farther into the wheelbase, thus (possibly, case specific) interfering with the brake system. The best bet is to talk with the company selling the wheel and make sure that it is a proper fit not just based on bolt pattern, but also center bore and offsets...they should have measured it up to the vehicle before they list the wheel for it

BFE TITAN · 05-22-2007, 09:19 PM

Quote:

Originally Posted by Spencer@tirerack

Offsets are a funny thing, and it is a rather common myth that there are specific approved offsets. This is logically, not true. ie. you can have two wheels, the exact same size and offsets, one someone can tell you that the specific offset will work. problem is, one of the wheels has a deep dish and this the spokes move farther into the wheelbase, thus (possibly, case specific) interfering with the brake system. The best bet is to talk with the company selling the wheel and make sure that it is a proper fit not just based on bolt pattern, but also center bore and offsets...they should have measured it up to the vehicle before they list the wheel for it

Thanks for the info. The problem I am running into is with the new spindle that comes with the lift, lots of places cant tell me if I will have an issue or not. I was just curious to know what some current members are running. I am fully prepared to trim a little bit, I just dont want to have an issue with anything rubbing the spindle. Would an incorrect offset even give me issues with interference with the spindle or would it just give me rubbing issues with the inner fender?? I want to get an 18x10 but most wheels that size have a -20 or -25 offset.

NorCal 4x4 · 05-22-2007, 09:56 PM

Offsets are use for calculating backspacing. An 8", 8.5", 9", etc. will all have different offsets for a given backspacing, (measurement of rim laying on a flat surface to the mounting surface). Even a 100" wide rim with the correct backspacing won't rub the spindle.

Stock backspacing is 5.5" for SE/LE and 5.43 for XE and Off Road rims. If I remember correctly, people run stock rims with the CST 4" spindle.

Yet CST states a 4.75" backspacing is required. If people are running stock rims with them, whoever stated the 4.75 bs at their website doesn't calculate backspacing correctly, (the way the wheel manufactures and most e-tailers do). [An 8" rim is really closer to 9", a 9" closer to 10", etc.].

If you can confirm that people are running stock rims with the spindle, then their backspacing should be fine. Many aftermarket rims have a 4.5" backspacing that pushes the rim out an inch, making it more of a deep dish. More clearance from the spindle, but more likely to rub at the pinch weld, (which btw, has an easy fix).

Stock 8" SE/LE 5.5" backspacing = +25mm offset

Stock 7.5" XE/OR 5.43" backspacing = +30mm offset

9" aftermarket with 5.5" backspacing = +12 mm offset
9" aftermarket with 5.0" backspacing = 0 mm offset
9" aftermarket with 4.5" backspacing = -12mm offset

AgTitan06 · 05-23-2007, 12:43 AM

You can fit 35s on the stock 18" rim, but the back of the tire will rub against the spindles.

I have the spindle and adjustable coilovers on mine..My rims are 18x9 with +3mm offset, with 5.14" backspacing. This still required the pinch weld mod, but no more rubbing now.