I would like HELP please !!! News wheels for my GMC

[Marder-Did]

I really need your help!
sorry for my english...

I want to change my wheels but I have a lot of difficulties to know if the wheels that I want can be set up on my truck and especially: without modification.
My truck is a GMC High sierra of 1979, it's stock.

In France, the dealers are more accustomed to Mustang (there is some everywhere) and Corvette, the trucks (70 - 80) are rare and often of years 50 - 60. The dealers cannot certify me that the wheels are going to go on my GMC and the sum to spend is : 1890 euros (for 4)
It is expensive if I am mistaken! I am therefore in a dead end.

I looked at all pages of this forum about the wheels or the photos of the trucks. Many owners installed very beautiful wheels of different constructors but I could not know if it was necessary to make some modifications.

Therefore, I want to put wheels 20" 8.5. On the internet site of American Racing, these 2 models could be set up on my truck, to be sure I asked the question but I didn't have an answer. One day perhaps ? But I hope some help of forum members.
I made a summary of the informations on this forum, if I understood well: Wheels in 20" 8 or 8.5 in the front = no modification (but Offset and backspace?) wheels of 20" 10 to the rear = no modification (Offset and backspace??)

2 models please me :
with an Offset of 0 mm but the Backspace?
http://www.americanracing.com/wheels...MC&model=C1500

with Offset of 15 mm but the Backspace?
http://www.americanracing.com/wheels...MC&model=C1500

MY QUESTION: these wheels of 20" are 8.5 you set up them on my truck WITHOUT modification? I ignore the famous and important backspace...

Do the owners can them to tell me merely (my English is very basic) if that is ok or no?

I am very thankful for your possible help.
Thank you to read me.
Cordially
Didier

[geezer#99]

Easy to figure all that stuff out yourself. With a tape and some other parts you can measure your truck.
Look here.
http://www.hotrod.com/how-to/wheels-...heels-fitment/

If you don't want to make your own jig then you can buy a tool to help you measure.
Like this.
http://www.summitracing.com/int/part...1201/overview/

[SCOTI]

If you know the offset, you just need to convert it to know the back-spacing. Locate the wheel width, scroll across the chart to the known offset (printed in black). Once that is found, scroll up to determine the back-spacing (printed in Red).

For 20x8" wheels in front, the '0' offset will work (4.5" back-space).
For 20x10" wheels in back, the '0' offset will work (5.5" back space) but the '-12' would be best (5.0" back space).

[Marder-Did]

Ok I see. Thank's for replys

For my c1500 it's planned +10 to -10 for the offset, is there a tolerance to these numbers so that goes without problem?

I have see very beautiful wheel but in offset for one on 13 and others in 18... (I think to much for the last offset... but perhaps ...

[SCOTI]

Originally Posted by Marder-Did

Ok I see. Thank's for replys

For my c1500 it's planned +10 to -10 for the offset, is there a tolerance to these numbers so that goes without problem?

I have see very beautiful wheel but in offset for one on 13 and others in 18... (I think to much for the last offset... but perhaps ...

It will depend on how wide they are (+10 to -10 is different on an 8", 8.5" & 10" wheel).

[Marder-Did]

Oupssss sorry...... it's for a 20" 8.5..... i see on diagram 8.5 - 5.5 backspace = offset 19... wheels i have see have offset 13 ... I approach the +10 of the origin. So I think it's good but ... again am not sure !

But for offset 18... it's another history...

[SCOTI]

Originally Posted by Marder-Did

Oupssss sorry...... it's for a 20" 8.5..... i see on diagram 8.5 - 5.5 backspace = offset 19... wheels i have see have offset 13 ... I approach the +10 of the origin. So I think it's good but ... again am not sure !

But for offset 18... it's another history...

20x8.5 with +19 offset would be 5.5"bs.
20x8.5 with +12 offset would be 5.25"bs.

A +13 offset would put you around 5.3"bs so they will work in front.

If you want to run the same size in the rear, they would work but they would be tucked deeper into the body when compared to the fronts. That looks awkward to me (and many others).

[Marder-Did]

I really appreciate your answer.
Thank again

[SCOTI]

Originally Posted by Marder-Did

I really appreciate your answer.
Thank again

You inform us.... we will try to help you.

[Marder-Did]

Finally. My news wheels Vision Torque in 20" front (8.5") and rear (9.5)
[IMG][/IMG]

Thank's for help !

[SCOTI]

What did you end up with for sizes & offsets?