oem gmc wheel backspacing and offset?

[diggman08]

can someone tell me the backspacing and offset to the OEM gmc 20's SLT high polished wheels?

 

are they same as the 18" chevy Z71 wheels?

 

if I have 7/8" spacers would this give the oem wheels a more positive offset or backspacing?

 

thanks

[crafferty]

Your going to have to post more details than just the size of the wheel. Posting a picture of the wheel in question would help the most. There are numerous wheel and tire combinations for these vehicles from the factory. Now they could be all the same backspacing too, I personally don't know that. I do believe the OEM Sport Package wheels that came on my Silverado were +23 offset.

 

[newdude]

27MM for factory 20" and 24MM for 18" factory.

[Rawyzf]

can someone tell me the backspacing and offset to the OEM gmc 20's SLT high polished wheels?

 

are they same as the 18" chevy Z71 wheels?

 

if I have 7/8" spacers would this give the oem wheels a more positive offset or backspacing?

 

thanks

 

Let say you have 20x9 +27. I think that is what most of them are.

 

With 7/8 spacers, you're going to push you wheels out that 7/8" which equal about 21mm. So, take your +27 offset and remove 21. That would have you sitting at 20x9 +6 (give or take a MM).

 

Regarding your question, the offset on the OEM wheel is not changing, you're just pushing them out to appear as if you had a 20x9 +6 wheel on the truck.

[diggman08]

ok thanks guys, great info. and the backspacing 5" or so?

 

trying to make sure I can clear some larger tires from the new UCA's. they are large than OEM so if using factory wheels it will rub because of the offset. the spacers will push em out just enough to clear UCA. from what im told at least.

 

do you guys think that doing just the front will be noticeable to the naked eye when comparing to the rear with 7/8" spacers.

 

crafferty,

actually SLT get chrome 20's. SLE get high polished 20's or 18's. One style for each. same with chevy. if they aren't these styles. then they are special order wheels from GM. which is optional.

 

so when I say gmc SLT high polished 20" wheel. theres only one it could possibly be.

btw, that sport package is SICK

[Rawyzf]

You'll have to google for an offset to backspace calculator, I am not sure on that one.

 

As for noticing 7/8 difference from front to back, I'd notice that in a heartbeat. I say run the spacers all around if that is your plan, or find wheels/tires that fit your ride height.

[diggman08]

apparently with the larger UCAs you cant run oem wheels. im gonna see how looks and then decide if want rear spacers. I may go with a narrow tire now that im pushing them out 1" basically. maybe like a 34x11

[POS VETT]

7/8 inch is actually a bit over 22 mm.

 

Backspacing to offset calculation is just a tad more involved. The formula is

 

(W + 1)/2 - BS = OS

 

W = wheel nominal Width (inch)

BS = Back Spacing (inch)

OS = OffSet (inch)

 

To convert offset to mm, multiply the number by 25.4

[diggman08]

so 7/8" someone said I can just put them on front and wont be that noticeable compared to back. some say it will.

 

what do you guys think.. I only have purchased the front 2 so far. $150.00

[Rawyzf]

40K truck, don't cheap out on $150 spacer.

[Payton34]

I saw somewhere on this forum the backspace on the factory 20x9 is close to 6"

[diggman08]

$150 I thought was not cheap for spacer.

 

I was thinking $40 ebay spacers were the cheap ones.

 

are their more expensive ones?

[Rawyzf]

No, I mean don't cheap out by only getting 2 spacers, get 4 .

 

I always use these guys: http://www.motorsport-tech.com/bora.html

[Jordan Wells]

I have black 20" OEM wheels, I'm looking to run 305 50 20 tires on them with a 2" level and 2" wheel spacers. Think that will fit?

[Lgetz]

I have black 20" OEM wheels, I'm looking to run 305 50 20 tires on them with a 2" level and 2" wheel spacers. Think that will fit?

Do the 305/55/20 instead. Taller tire which will fill in the wheel wells much better. I have read people doing only a 2.5 inch level and barely rubbing the sway bar. With your spacers should be even less of an issue.