Front spacing/Back spacing question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

72chevynoob · 10-11-2012, 11:55 PM

I am switching my truck from 6 to 5 lug in the front, with spindles and rotors from a 1981 silverado. I plan on keeping the rear 6 lug and just running the same brand of rallyes on the rear with smoothie hub caps. i am wondering what the front spacing or back spacing should be for them to look and work the best. The rears will be 15x10 or 15x12 and the fronts will be 15x8 or 15x9.
Thanks

Pondscum · 10-13-2012, 11:05 AM

bump

**CC69Rat** · 10-13-2012, 03:11 PM

Stepside or Fleetside? Lowered or stock height?

72chevynoob · 10-13-2012, 05:33 PM

Fleetside. Stock height but it will get lowered ptobably 4/6
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**lolife99** · 10-13-2012, 06:17 PM

What year truck?

**CC69Rat** · 10-13-2012, 06:25 PM

6 lug 72 ? ( .. from his forum name )
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72chevynoob · 10-13-2012, 06:27 PM

Haha not a 72- a 69. I was looking for a 72 when i joined, though.
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**CC69Rat** · 10-13-2012, 06:29 PM

Do you know if it's early or late rear end housing?
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**lolife99** · 10-13-2012, 06:32 PM

You have several issues that need to be addressed.
15 inch wheels is the first one.
Your front wheels can not have more than a 4" backspace, and you will probably need to do a little trimming of the lower a-arms to make them work with spindles.
With that said,... I would use a 15x7 wheel to tuck them under the fenders nicely.
The rear will work with a 15x10 with a 4.75"-5" backspace.
Finding tires for a 15x10 or 15x12 might be tough unless you go with a Mickey Thompson tire.
My opinion,... I think a 275/60 looks stretched on a 15x10,... and a 295/50 looks too short.

Your 4/6 drop is the perfect drop!

**lolife99** · 10-13-2012, 06:33 PM

Quote:

Originally Posted by CC69Rat

Do you know if it's early or late rear end housing?
Posted via Mobile Device

Should be the early 67-69 (narrower) rearend if it's original to the truck.

72chevynoob · 10-13-2012, 06:44 PM

Im pretty sure its original, it is a 12 bolt and it has the 6 lug drums. It is quite a bot narrowetr than the front as well, so i think it is.
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72chevynoob · 10-13-2012, 07:20 PM

What do you mean when you say that a 275/60 looks stretched?

**lolife99** · 10-13-2012, 07:22 PM

Quote:

Originally Posted by 72chevynoob

What do you mean when you say that a 275/60 looks stretched?

In my opinion,... a 275/60 looks better on a 15x8.

**CC69Rat** · 10-13-2012, 07:43 PM

If you can, lay under the back of the truck and measure from one backing plate to the other. Is it 55.5" or 57" wide. .. (lolife99's method actually)
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**CC69Rat** · 10-13-2012, 07:56 PM

275 / 25.4 = 10.82 in

25.4 cm in one inch. 275 tire is 275cm wide.

Multiply in inches x the aspect ratio to get the sidewall height.

Ex. 275/60/15 would look like this. 275/25.4*.60 = 6.49in sidewall. Top + bottom sidewall + rim size = overall size. 6.5+6.5+15 = 28in tall.

295/50/15. 295/25.4*.50*2+15. 5.8" sidewall but only 26.6" tall. 'Wide and short'

Make sense?
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72chevynoob · 10-13-2012, 08:19 PM

Quote:

Originally Posted by CC69Rat

If you can, lay under the back of the truck and measure from one backing plate to the other. Is it 55.5" or 57" wide. .. (lolife99's method actually)
Posted via Mobile Device

It is 55.5 inches, so probabvy the original axle
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72chevynoob · 10-13-2012, 09:11 PM

Thanks for explaining this to me guys. if i went with 16" rallyes from summit could i go with 16x8s in the front without having to trim the a-arms? 15x8s seemed to work pretty good in the truck i pulled the spindles off of, although i have no clue what the backspacing is on those rims.
Posted via Mobile Device

ChevLoRay · 10-13-2012, 10:58 PM

Maybe this'll help....On my '96 GMC with DJM spindles up front, I went with Wheel Vintique 'Vette style rallye wheels in a 16x7 size with a 4-inch backspace. Before that, it had 15x7's up front and 15x8's out back. I had to go with the 7's because a 4-inch backspace would let the inside of the wheels contact the lower control arms when turning. I know some folks don't have any qualms about trimming them, but my thinking is that the engineers designed the shape of those control arms for a specific reason.

On my '69, I went with Early Classic Enterprises and a 2.5/4.0 drop. I kept the 6-lug patter on the disc conversion because of the wheels I had at the time. Since then, I went with Wheel Vintiques 15x8 up front, with a 4-inch backspace and 15x10's out back with a 5-inch backspace. Pre-disc brake steel wheels won't clear the rotors, but 6-lug 4WD wheels will work.

A.Bursell · 10-14-2012, 01:43 AM

Quote:

Originally Posted by ChevLoRay

On my '69, I went with Early Classic Enterprises and a 2.5/4.0 drop. I kept the 6-lug patter on the disc conversion because of the wheels I had at the time. Since then, I went with Wheel Vintiques 15x8 up front, with a 4-inch backspace and 15x10's out back with a 5-inch backspace. Pre-disc brake steel wheels won't clear the rotors, but 6-lug 4WD wheels will work.

Is it safe to say no trimming with stock spindles, but lowering spindles will contact or require trimming? This is with a 15x8 wheel.

Adam
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72chevynoob · 10-14-2012, 10:36 PM

So would 15x7 with 4" b.s. fit on cpp 2-1/2" drop spindles without having to trim or should i go to 16x7?
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**lolife99** · 10-15-2012, 06:59 AM

Quote:

Originally Posted by 72chevynoob

So would 15x7 with 4" b.s. fit on cpp 2-1/2" drop spindles without having to trim or should i go to 16x7?
Posted via Mobile Device

You would have to trim.

10-11-2012, 11:55 PM	#1
72chevynoob Registered User Join Date: Mar 2012 Location: Lacombe, Alberta Posts: 288	Front spacing/Back spacing question I am switching my truck from 6 to 5 lug in the front, with spindles and rotors from a 1981 silverado. I plan on keeping the rear 6 lug and just running the same brand of rallyes on the rear with smoothie hub caps. i am wondering what the front spacing or back spacing should be for them to look and work the best. The rears will be 15x10 or 15x12 and the fronts will be 15x8 or 15x9. Thanks __________________ Justin 69 lwb project: http://67-72chevytrucks.com/vboard/s...d.php?t=558011

10-13-2012, 11:05 AM	#2
Pondscum Registered User Join Date: Nov 2010 Location: Perry Missouri Posts: 72	Re: Front spacing/Back spacing question bump

10-13-2012, 03:11 PM	#3
CC69Rat Senior Member Join Date: Jan 2011 Location: Chattanooga TN Posts: 6,205	Re: Front spacing/Back spacing question Stepside or Fleetside? Lowered or stock height? __________________ Chad 1967 C10 SWB - Project Savannah - 6.0/4L80 Currently underway 1968 C10 SWB - TOTY 2018, 50th Anniversary Tribute Project * Sold * Pride and Joy 1986 Silverado Short Fleet - Scarlet Sold 1985 Silverado Short Fleet Sold 2022 Jeep Gladiator Mojave 2001 Jeep Cherokee XJ 4x4 - Lifted, Built 1992 Jeep Cherokee XJ 4x4 - Lifted 2013 Honda Accord EX-L v6 Coupe 6spd (wife's ride)

10-13-2012, 05:33 PM	#4
72chevynoob Registered User Join Date: Mar 2012 Location: Lacombe, Alberta Posts: 288	Re: Front spacing/Back spacing question Fleetside. Stock height but it will get lowered ptobably 4/6 Posted via Mobile Device __________________ Justin 69 lwb project: http://67-72chevytrucks.com/vboard/s...d.php?t=558011

10-13-2012, 06:17 PM	#5
lolife99 67-72 parts collector,… Join Date: Nov 2002 Location: Mid-MO Posts: 22,681	Re: Front spacing/Back spacing question What year truck? __________________ Keith Convert to disc brakes. http://67-72chevytrucks.com/vboard/s...d.php?t=444823

10-13-2012, 06:25 PM	#6
CC69Rat Senior Member Join Date: Jan 2011 Location: Chattanooga TN Posts: 6,205	Re: Front spacing/Back spacing question 6 lug 72 ? ( .. from his forum name ) Posted via Mobile Device __________________ Chad 1967 C10 SWB - Project Savannah - 6.0/4L80 Currently underway 1968 C10 SWB - TOTY 2018, 50th Anniversary Tribute Project * Sold * Pride and Joy 1986 Silverado Short Fleet - Scarlet Sold 1985 Silverado Short Fleet Sold 2022 Jeep Gladiator Mojave 2001 Jeep Cherokee XJ 4x4 - Lifted, Built 1992 Jeep Cherokee XJ 4x4 - Lifted 2013 Honda Accord EX-L v6 Coupe 6spd (wife's ride)

10-13-2012, 06:27 PM	#7
72chevynoob Registered User Join Date: Mar 2012 Location: Lacombe, Alberta Posts: 288	Re: Front spacing/Back spacing question Haha not a 72- a 69. I was looking for a 72 when i joined, though. Posted via Mobile Device __________________ Justin 69 lwb project: http://67-72chevytrucks.com/vboard/s...d.php?t=558011

10-13-2012, 06:29 PM	#8
CC69Rat Senior Member Join Date: Jan 2011 Location: Chattanooga TN Posts: 6,205	Re: Front spacing/Back spacing question Do you know if it's early or late rear end housing? Posted via Mobile Device __________________ Chad 1967 C10 SWB - Project Savannah - 6.0/4L80 Currently underway 1968 C10 SWB - TOTY 2018, 50th Anniversary Tribute Project * Sold * Pride and Joy 1986 Silverado Short Fleet - Scarlet Sold 1985 Silverado Short Fleet Sold 2022 Jeep Gladiator Mojave 2001 Jeep Cherokee XJ 4x4 - Lifted, Built 1992 Jeep Cherokee XJ 4x4 - Lifted 2013 Honda Accord EX-L v6 Coupe 6spd (wife's ride)

10-13-2012, 06:32 PM	#9
lolife99 67-72 parts collector,… Join Date: Nov 2002 Location: Mid-MO Posts: 22,681	Re: Front spacing/Back spacing question You have several issues that need to be addressed. 15 inch wheels is the first one. Your front wheels can not have more than a 4" backspace, and you will probably need to do a little trimming of the lower a-arms to make them work with spindles. With that said,... I would use a 15x7 wheel to tuck them under the fenders nicely. The rear will work with a 15x10 with a 4.75"-5" backspace. Finding tires for a 15x10 or 15x12 might be tough unless you go with a Mickey Thompson tire. My opinion,... I think a 275/60 looks stretched on a 15x10,... and a 295/50 looks too short. Your 4/6 drop is the perfect drop! __________________ Keith Convert to disc brakes. http://67-72chevytrucks.com/vboard/s...d.php?t=444823

10-13-2012, 06:44 PM	#11
72chevynoob Registered User Join Date: Mar 2012 Location: Lacombe, Alberta Posts: 288	Re: Front spacing/Back spacing question Im pretty sure its original, it is a 12 bolt and it has the 6 lug drums. It is quite a bot narrowetr than the front as well, so i think it is. Posted via Mobile Device __________________ Justin 69 lwb project: http://67-72chevytrucks.com/vboard/s...d.php?t=558011

10-13-2012, 07:20 PM	#12
72chevynoob Registered User Join Date: Mar 2012 Location: Lacombe, Alberta Posts: 288	Re: Front spacing/Back spacing question What do you mean when you say that a 275/60 looks stretched? __________________ Justin 69 lwb project: http://67-72chevytrucks.com/vboard/s...d.php?t=558011

10-13-2012, 07:43 PM	#14
CC69Rat Senior Member Join Date: Jan 2011 Location: Chattanooga TN Posts: 6,205	Re: Front spacing/Back spacing question If you can, lay under the back of the truck and measure from one backing plate to the other. Is it 55.5" or 57" wide. .. (lolife99's method actually) Posted via Mobile Device __________________ Chad 1967 C10 SWB - Project Savannah - 6.0/4L80 Currently underway 1968 C10 SWB - TOTY 2018, 50th Anniversary Tribute Project * Sold * Pride and Joy 1986 Silverado Short Fleet - Scarlet Sold 1985 Silverado Short Fleet Sold 2022 Jeep Gladiator Mojave 2001 Jeep Cherokee XJ 4x4 - Lifted, Built 1992 Jeep Cherokee XJ 4x4 - Lifted 2013 Honda Accord EX-L v6 Coupe 6spd (wife's ride)

10-13-2012, 07:56 PM	#15
CC69Rat Senior Member Join Date: Jan 2011 Location: Chattanooga TN Posts: 6,205	Re: Front spacing/Back spacing question 275 / 25.4 = 10.82 in 25.4 cm in one inch. 275 tire is 275cm wide. Multiply in inches x the aspect ratio to get the sidewall height. Ex. 275/60/15 would look like this. 275/25.4.60 = 6.49in sidewall. Top + bottom sidewall + rim size = overall size. 6.5+6.5+15 = 28in tall. 295/50/15. 295/25.4.502+15. 5.8" sidewall but only 26.6" tall. 'Wide and short' Make sense? Posted via Mobile Device* __________________ Chad 1967 C10 SWB - Project Savannah - 6.0/4L80 Currently underway 1968 C10 SWB - TOTY 2018, 50th Anniversary Tribute Project * Sold * Pride and Joy 1986 Silverado Short Fleet - Scarlet Sold 1985 Silverado Short Fleet Sold 2022 Jeep Gladiator Mojave 2001 Jeep Cherokee XJ 4x4 - Lifted, Built 1992 Jeep Cherokee XJ 4x4 - Lifted 2013 Honda Accord EX-L v6 Coupe 6spd (wife's ride)

10-13-2012, 09:11 PM	#17
72chevynoob Registered User Join Date: Mar 2012 Location: Lacombe, Alberta Posts: 288	Re: Front spacing/Back spacing question Thanks for explaining this to me guys. if i went with 16" rallyes from summit could i go with 16x8s in the front without having to trim the a-arms? 15x8s seemed to work pretty good in the truck i pulled the spindles off of, although i have no clue what the backspacing is on those rims. Posted via Mobile Device __________________ Justin 69 lwb project: http://67-72chevytrucks.com/vboard/s...d.php?t=558011 Last edited by 72chevynoob; 10-13-2012 at 09:28 PM.

10-13-2012, 10:58 PM	#18
ChevLoRay Old Skool Club Join Date: Jun 2001 Location: Benton, AR "The Heart of Arkansas" Posts: 10,880	Re: Front spacing/Back spacing question Maybe this'll help....On my '96 GMC with DJM spindles up front, I went with Wheel Vintique 'Vette style rallye wheels in a 16x7 size with a 4-inch backspace. Before that, it had 15x7's up front and 15x8's out back. I had to go with the 7's because a 4-inch backspace would let the inside of the wheels contact the lower control arms when turning. I know some folks don't have any qualms about trimming them, but my thinking is that the engineers designed the shape of those control arms for a specific reason. On my '69, I went with Early Classic Enterprises and a 2.5/4.0 drop. I kept the 6-lug patter on the disc conversion because of the wheels I had at the time. Since then, I went with Wheel Vintiques 15x8 up front, with a 4-inch backspace and 15x10's out back with a 5-inch backspace. Pre-disc brake steel wheels won't clear the rotors, but 6-lug 4WD wheels will work. __________________ 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.



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10-14-2012, 10:36 PM	#20
72chevynoob Registered User Join Date: Mar 2012 Location: Lacombe, Alberta Posts: 288	Re: Front spacing/Back spacing question So would 15x7 with 4" b.s. fit on cpp 2-1/2" drop spindles without having to trim or should i go to 16x7? Posted via Mobile Device __________________ Justin 69 lwb project: http://67-72chevytrucks.com/vboard/s...d.php?t=558011

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