Wheel Offset - The 1947 - Present Chevrolet & GMC Truck Message Board Network

craigg1 · 07-13-2004, 08:55 PM

Ok, im trying to figure out the offset for some new wheels on my 68 SWB truck. Im wanting to get some 17x8 rims. Truck is a 6 lug with a 5.5 bolt pattern. Can anyone tell me the backspacing and the offset that I need to look for when getting the 17x8 rims?

Tx Firefighter · 07-13-2004, 09:07 PM

I always use 4 1/4 or 4 1/2 inch backspacing on an 8 inch wheel. A stock 8 inch 5 lug rally wheel is 4 1/4 backspace and they fit like a glove. My rear Cragars are also 4 1/4 and they fit real well too of course.

They work well under deeply lowered trucks, which is what mine always are.

ChevLoRay · 07-13-2004, 09:07 PM

Drums or discs?

The 17 inch diameter wheels will clear both the drum and the discs. You will want more offset for the front wheels to keep them from sticking outside of the fender line, if you have discs on the front. As for the rear, you should be able to go with 3.5-4.0 inch offset, I believe. I think 4 inches is the stock offset for the aluminum wheels on the 88-98's. That is what my 15x8's have on the back of my '69. I went to a 15x7 on the front, when I converted the drums to discs.

I guess in theory, you would want to keep the centerline of the wheel positioned in such a way that it didn't have too much of the wheel and tire outside or inside of that centerline. Either way, and it stresses the front end. Sometimes, folks who do alignments won't mess with them. So, you might talk to an alignment shop and see what they have to say, if they know.

cdowns · 07-13-2004, 09:21 PM

if you want to see what not to do with wheel offset "dinnut" has a current post titled "this really bites" you look at the pictures and see the severe offset of his rims not to mention that the lug holes are 3/8" too large for the studs and he's posted the resulting failure
if you're not really familiar with how to pick a wheel go shopping to a large long-established shop that deals in aftermarket and spend some time talking and getting an education about what's the proper way to select a rim

PunkRock247 · 07-14-2004, 05:09 PM

Hey Craigg1,

Did you end up getting the wheels you were talking about in this thread?

If so I can't wait to see how they look, please post some pics when you get them on.

craigg1 · 07-14-2004, 05:13 PM

PunkRock247, I ordered the wheels and they should hopefully be here within a week or two. I will post pics when I get them on the truck.

Vince M · 07-14-2004, 05:58 PM

There seems to be some confusion on the term "offset" and "backspace". They are not the same thing. Backspace is exactly as it is desribed. It is the distance from the edge of the inside lip to the inside face of the center hub of the wheel. Offset is the distance from the centerline of the wheel. This can be plus or minus. An 8" rim with a 4" backspace has "0" offset.

Hope this helps

07-13-2004, 08:55 PM	#1
craigg1 Registered User Join Date: Jun 2003 Location: Beaumont, Tx Posts: 280	Wheel Offset Ok, im trying to figure out the offset for some new wheels on my 68 SWB truck. Im wanting to get some 17x8 rims. Truck is a 6 lug with a 5.5 bolt pattern. Can anyone tell me the backspacing and the offset that I need to look for when getting the 17x8 rims?

07-13-2004, 09:07 PM	#2
Tx Firefighter Watch out for your cornhole ! Join Date: Jun 2003 Location: Azle, Texas Posts: 14,162	I always use 4 1/4 or 4 1/2 inch backspacing on an 8 inch wheel. A stock 8 inch 5 lug rally wheel is 4 1/4 backspace and they fit like a glove. My rear Cragars are also 4 1/4 and they fit real well too of course. They work well under deeply lowered trucks, which is what mine always are. __________________ I'm on the Instagram- @Gearhead_Kevin Last edited by Tx Firefighter; 07-13-2004 at 09:10 PM.

07-13-2004, 09:07 PM	#3
ChevLoRay Old Skool Club Join Date: Jun 2001 Location: Benton, AR "The Heart of Arkansas" Posts: 10,880	Drums or discs? The 17 inch diameter wheels will clear both the drum and the discs. You will want more offset for the front wheels to keep them from sticking outside of the fender line, if you have discs on the front. As for the rear, you should be able to go with 3.5-4.0 inch offset, I believe. I think 4 inches is the stock offset for the aluminum wheels on the 88-98's. That is what my 15x8's have on the back of my '69. I went to a 15x7 on the front, when I converted the drums to discs. I guess in theory, you would want to keep the centerline of the wheel positioned in such a way that it didn't have too much of the wheel and tire outside or inside of that centerline. Either way, and it stresses the front end. Sometimes, folks who do alignments won't mess with them. So, you might talk to an alignment shop and see what they have to say, if they know. __________________ Member Nr. 2770 '96 GMC Sportside; 4.3/SLT - Daily driven....constantly needs washed. '69 C-10 SWB; 350/TH400 - in limbo The older I get, the better I was.

07-13-2004, 09:21 PM	#4
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	if you want to see what not to do with wheel offset "dinnut" has a current post titled "this really bites" you look at the pictures and see the severe offset of his rims not to mention that the lug holes are 3/8" too large for the studs and he's posted the resulting failure if you're not really familiar with how to pick a wheel go shopping to a large long-established shop that deals in aftermarket and spend some time talking and getting an education about what's the proper way to select a rim __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY

07-14-2004, 05:09 PM	#5
PunkRock247 Registered User Join Date: Dec 2002 Location: Antelope, CA Posts: 44	Hey Craigg1, Did you end up getting the wheels you were talking about in this thread? If so I can't wait to see how they look, please post some pics when you get them on. __________________ 1969 Chevrolet C-10 SWB

07-14-2004, 05:13 PM	#6
craigg1 Registered User Join Date: Jun 2003 Location: Beaumont, Tx Posts: 280	PunkRock247, I ordered the wheels and they should hopefully be here within a week or two. I will post pics when I get them on the truck.

07-14-2004, 05:58 PM	#7
Vince M Senior Member Join Date: Apr 2000 Location: Orlando, FL Posts: 1,076	There seems to be some confusion on the term "offset" and "backspace". They are not the same thing. Backspace is exactly as it is desribed. It is the distance from the edge of the inside lip to the inside face of the center hub of the wheel. Offset is the distance from the centerline of the wheel. This can be plus or minus. An 8" rim with a 4" backspace has "0" offset. Hope this helps __________________ ............................................................ 68 Chevy CST SWB w/LS1, carb & 700r4. Golden Anniversary clone with a few improvements.



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