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I know how backspace works measuring etc. I have a math problem for you guys.

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Old 05-06-2012, 07:05 PM
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formerly 2low4nd (11-08-2011)
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Question I know how backspace works measuring etc. I have a math problem for you guys.

I know how backspace works measuring etc. I have a math problem for you guys.

My brain is locking up at this point. I beleave im over thinking this.

Here we go.

Ive figured these wheels.
here is the new link.
http://www.carid.com/giovanna-wheels...me-348140.html
with a 20x8.5 with a +35mm offset with a 2" adapter should tuck in front.

Rears 20x10 with a +35mm offset. They also offer the rear in a +75 offset thats a big difference. The more i try to do the math the more lost im getting.

Here is a chart im trying to use as well. If this was all in inches this wouldnt be a big deal. Ive been trying to figure this out for the last 2 ours.

Here is a chart ive been using to try to do the math.

https://www.rsracing.com/tech-wheel.html

My truck requires a +30 offset to tuck a normal 20" wheel normally. But with this two inch adapter or there is another brand that has a 1 1/2" adapter also. its throwing me off.


Last edited by 1FSTGMC; 05-09-2012 at 09:58 PM.
Old 05-06-2012, 10:24 PM
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formerly 2low4nd (11-08-2011)
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looks like im going to have to go with the most +offset number in order to tuck with the adapter. Run a stretched tire to tuck the setup.
Old 05-08-2012, 10:07 AM
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I tried to pull the link up, but says not found. Think I found the wheels anyways...

If I had the right wheel, they only come in a 5 lug. Are you swapping over to a 5 lug setup? If not and you have to use adapters to get to 5 lugs, I saw more than the couple of backspacing options you listed.

Weren't you doing racelines? Or maybe it was intros? What happened to that?

Here is a formula I found real quick to help calculate..."For positive offset wheels: (Wheel Width +1)/2 + (offset * .03937)" With the chart you posted, the calculation seems to come out really close
Old 05-09-2012, 09:44 PM
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I worded it wrong. Im using 1 1/2 adapters not spacers If i could make this work.
Im having trouble converting mm to inches. I was going to go racelines, but dont want the truck down again. Its getting nice out and want to drive the damn thing. With racelines and narrow i will still have about 4k into the damn thing. Just getting sick of sticking so much money into it. Just looking for something different in a different way. I hate 99.9 percent of the wheels offered for the 6 lug bolt pattern so trying to think outside the box. Something different with a nice wheel.

I really have to find out how close i would be. Just need a confermation someone else to run the numbers with me.


Here is another link of the wheels see if this works.

http://www.carid.com/giovanna-wheels...me-348140.html

Last edited by 1FSTGMC; 05-09-2012 at 09:56 PM.
Old 05-09-2012, 10:31 PM
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Looks like it will work.

Found a better chart. From the specs i posted with a 1.25" thick adapter 6 to 5 lug it will be close. My truck is on a 4/6 drop.

Here is a link to the new chart i found.

Wheel Specs | Wheel Specialists, Inc.
Old 05-09-2012, 11:24 PM
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Damn man those are going to look good.
Old 05-09-2012, 11:38 PM
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Originally Posted by silverado2000
Damn man those are going to look good.
Yes, thank you. If i can make them work they will be sick. Such a hi quality wheel if i run a semi stretched tire on them on my 4/6 drop, if my calculations are correct i will have about 1/2 or less before they stick outside of the fender. I already have rolled fenders so it should work out. Prob run a 255/35-20 tire in front and a 275/35-20 in the rear.
Old 05-10-2012, 11:01 AM
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Ok, trying to work this out with you...

With the 8.5 front and 35mm offset, I get a backspace of 6.1"
With the 10 rear and a 35mm offset, I get a backspace of 6.8"
With the 10 rear and a 75m offset, I get a backspace of 8.4"

Now, if you add in 1.25" adapters, you front essentially has 4.85" backspacing, and rear with 35mm has 5.55". Rear with 75mm has 7.2"

I ran 20x8s with a 5" backspacing and they were really close to flush. I did not have rolled or cut fenders (stepside bed). Here is a pic of how close mine were, and this is with a 245/40/20 tire



Your front will being a wider wheel, and less backspacing will be about .75" further out than mine. The rear 35mm, even with .5" extra backspacing, you are adding 2" of width, so they will stick out about 1.5" further than mine. The rear 75mm, will only stick out about .25" more

I believe my calculations are correct, I did them several times to be certain. With that said, I THINK you should be ok in the front, might have to run some neg camber to be sure, and the rear with only .25" difference should be fine with rolled lips.

With all of that said, why run a 10" wheel and a 275 tire? I ran 275s on my 8" wheels and liked the look better than if it was stretched. If you like the stretched look, so be it. Personally a 275 fits a 9" best IMO
Old 05-10-2012, 11:12 AM
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Just realized I read the adapter size as 1.25, not 1.5

So everything will stick out another .25" from what I originally put above. I think the front is going to be too close

What 5 lug pattern are you going with? I see a 45mm offset in a 5x112
Old 05-10-2012, 11:46 AM
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Originally Posted by 02BlueStepside
Just realized I read the adapter size as 1.25, not 1.5

So everything will stick out another .25" from what I originally put above. I think the front is going to be too close

What 5 lug pattern are you going with? I see a 45mm offset in a 5x112
1.25 is less then 1.50 there for they would sit inward .25 more then the math done with 1.50. Not out ward

Your Truck looks good by the way!!! I may be biased though since my Silvy is the same color.... LOL


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