Backspacing in 71-72 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

c1069 · 01-06-2011, 11:53 PM

Hi I want to make a change in my truck. I did the swap of 6 lug to 5 and I need to know the backspacing on some new wheels. I want to put 8" in front and 10" on back. Please any input would be appreciated. Thanks.

stefan · 01-08-2011, 02:23 AM

Did you do the just the axle conversion or didyou put a 71 or 72 rearend.Iknow someone here can help.

**lolife99** · 01-08-2011, 02:27 AM

Stock height?
Static dropped?
Air ride?

What's your suspension plans?

c1069 · 01-09-2011, 12:20 AM

Quote:

Originally Posted by stefan

Did you do the just the axle conversion or didyou put a 71 or 72 rearend.Iknow someone here can help.

71 rear end

Quote:

Originally Posted by lolife99

Stock height?
Static dropped?
Air ride?

What's your suspension plans?

dropped

72BlckButy · 01-09-2011, 12:22 AM

Quote:

Originally Posted by c1069

71 rear end

dropped

Dropped how? Static, bags, etc.

In order to provide assistance to your question, we need to have more background into what you're dealing with. Also... what size wheel do you want to run?

There's a lot that goes into determining the correct BS to run on a set of wheels for them to fit "right."

72BlckButy · 01-08-2011, 01:51 PM

What size wheels?

c1069 · 01-09-2011, 12:22 AM

Quote:

Originally Posted by 72BlckButy

What size wheels?

15" rallys

Spoof · 01-08-2011, 01:55 PM

Does it have air conditioning?

72BlckButy · 01-08-2011, 01:57 PM

Quote:

Originally Posted by Spoof

Does it have air conditioning?

Confused... Won't really affect the backspacing on a wheel.

Spoof · 01-08-2011, 02:32 PM

Sorry...after all the questions as to the particulars I couldn't help but mimic the obviously non-pertinent questions you get when you try to order a part at an auto supply store.

Me: I would like an oil filter
Parts person: what colour is your truck?

OldSkool71 · 01-09-2011, 12:55 AM

Quote:

Originally Posted by Spoof

Does it have air conditioning?

this is frickin hilarious....

**lolife99** · 01-08-2011, 03:06 PM

Spoof,... I understand your sarcasism.
But sometimes it's like "pulling teeth" to get all info out of the OP.
I only ask questions when I don't have enough info to give a good answer.

The wheel diameter is very important when it comes to backspacing numbers.
So is the amount of drop.

Spoof · 01-08-2011, 06:08 PM

I'm sorry guys, I came across as making fun of you. I was trying to be funny but I wasn't inferring that any of the questions asked by members were irrelevant, in fact they were very pertinent and necessary to answer the bs question.
No dig or passive aggressiveness was intended, only a poke at parts store clerks!
Sorry to derail the post.
If it helps...my 18"X9.5" rear are 4.5" bs and the 18"X8" fronts are 4" bs.
4" drop springs back, 2.5 spindles front.

stefan · 01-09-2011, 12:18 AM

Hey Lolife you have always given me good advice,so lets do mine im about to buy wheels in i hope a month,my truck is a 5.5 front and 8 inch in the rear and i want 17 or 18 inch wheels 8.5 in front and 10 inch in the rear and the truck is a 72 swb,thanks bud

**lolife99** · 01-09-2011, 12:44 AM

Quote:

Originally Posted by stefan

Hey Lolife you have always given me good advice,so lets do mine im about to buy wheels in i hope a month,my truck is a 5.5 front and 8 inch in the rear and i want 17 or 18 inch wheels 8.5 in front and 10 inch in the rear and the truck is a 72 swb,thanks bud

If you ever plan on bagging it,... you have to tuck the wheels enough,... so they will clear when air'd out.
But for a static drop:

8.5" wheel in the front:
I would use a 5.25"-5.5" backspace.

10" wheel in the rear,... (with the wider 71-72 rearend housing).
I would use a 5.5" backspace.

72BlckButy · 01-09-2011, 12:25 AM

If by dropped you mean staticly... how low are you? 2/4, 3/5, 4/6?

With running a set of rallys, all you should need on a 4" drop in the front will be a creative grinding on the lower a-arm since you are running disc brakes.

c1069 · 01-09-2011, 12:42 AM

Quote:

Originally Posted by 72BlckButy

If by dropped you mean staticly... how low are you? 2/4, 3/5, 4/6?

With running a set of rallys, all you should need on a 4" drop in the front will be a creative grinding on the lower a-arm since you are running disc brakes.

4/6 ....front disc

**lolife99** · 01-09-2011, 12:53 AM

Quote:

Originally Posted by c1069

4/6 ....front disc

OK,...
4/6 drop
15x8 and 15x10 ralleys.

It would be nice to run greater than a 5" BS up front,... but that's not possible. 4" BS is the most with a 15" rim,... and that will require a little grinding on the lower a-arm in the balljoint area.
An 8" rim up front with a 4" BS may be close to rubbing the fender lip with a 4" front drop. It all depends on tire height.
I usually run a 7" rim up front when I use 15" wheels with that much drop.

The rear 10" ralleys will work with a 5"-5.5" BS.

Here's my '69 with a 5.5/7 drop on 15" truck ralleys.
(15x7's and 15x8's)

72BlckButy · 01-09-2011, 12:44 AM

Grind the a-arm.

Refer to:

http://67-72chevytrucks.com/vboard/s...4&postcount=61

Please provide enough information when asking for assistance; it really helps to determine everything that is involved.

c1069 · 01-09-2011, 12:52 AM

Quote:

Originally Posted by 72BlckButy

Grind the a-arm.

Refer to:

http://67-72chevytrucks.com/vboard/s...4&postcount=61

Please provide enough information when asking for assistance; it really helps to determine everything that is involved.

Thanks. I'll keep that in mind next time.

72BlckButy · 01-09-2011, 12:56 AM

Everything that lolife99 posted above is covered in the following two threads:

Project NO-Life: http://67-72chevytrucks.com/vboard/s...hlight=no-life

Project Blank Slate: http://67-72chevytrucks.com/vboard/s...d.php?t=353633

01-06-2011, 11:53 PM	#1
c1069 Registered User Join Date: Apr 2010 Location: McFarland CA Posts: 1,392	Backspacing in 71-72 Hi I want to make a change in my truck. I did the swap of 6 lug to 5 and I need to know the backspacing on some new wheels. I want to put 8" in front and 10" on back. Please any input would be appreciated. Thanks.

01-08-2011, 02:23 AM	#2
stefan New Member Join Date: Sep 2006 Location: texas Posts: 118	Re: Backspacing in 71-72 Did you do the just the axle conversion or didyou put a 71 or 72 rearend.Iknow someone here can help. Last edited by stefan; 01-08-2011 at 02:24 AM.

01-08-2011, 02:27 AM	#3
lolife99 67-72 parts collector,… Join Date: Nov 2002 Location: Mid-MO Posts: 22,700	Re: Backspacing in 71-72 Stock height? Static dropped? Air ride? What's your suspension plans? __________________ Keith Convert to disc brakes. http://67-72chevytrucks.com/vboard/s...d.php?t=444823

01-08-2011, 01:51 PM	#6
72BlckButy Tot Roddin' Join Date: Apr 2005 Location: Mid-MO Posts: 24,461	Re: Backspacing in 71-72 What size wheels? __________________ -Nate 1969 CST SWB - Project Blank Slate (4.5/6" ECE Static Drop, 6-lug disc brake upgrade (manual), Billet Specialties Vintec 20x8.5 255/40 (F) 20x10 295/40 (R), 250 I-6) 1960 AMF Skylark - Tot Roddin' (Lowered with custom frame; soon to include custom push bar and interior) 2008 Silverado CrewCab 1LT (5.3L, 3:73, 4x4, LT1, Z-71, Towing Package)

01-08-2011, 01:55 PM	#8
Spoof Registered User Join Date: Jul 2000 Location: Victoria,BC, Canada Posts: 1,300	Re: Backspacing in 71-72 Does it have air conditioning? __________________ 71 GMC 1500 LWB

01-08-2011, 02:32 PM	#10
Spoof Registered User Join Date: Jul 2000 Location: Victoria,BC, Canada Posts: 1,300	Re: Backspacing in 71-72 Sorry...after all the questions as to the particulars I couldn't help but mimic the obviously non-pertinent questions you get when you try to order a part at an auto supply store. Me: I would like an oil filter Parts person: what colour is your truck? __________________ 71 GMC 1500 LWB

01-08-2011, 03:06 PM	#12
lolife99 67-72 parts collector,… Join Date: Nov 2002 Location: Mid-MO Posts: 22,700	Re: Backspacing in 71-72 Spoof,... I understand your sarcasism. But sometimes it's like "pulling teeth" to get all info out of the OP. I only ask questions when I don't have enough info to give a good answer. The wheel diameter is very important when it comes to backspacing numbers. So is the amount of drop. __________________ Keith Convert to disc brakes. http://67-72chevytrucks.com/vboard/s...d.php?t=444823

01-08-2011, 06:08 PM	#13
Spoof Registered User Join Date: Jul 2000 Location: Victoria,BC, Canada Posts: 1,300	Re: Backspacing in 71-72 I'm sorry guys, I came across as making fun of you. I was trying to be funny but I wasn't inferring that any of the questions asked by members were irrelevant, in fact they were very pertinent and necessary to answer the bs question. No dig or passive aggressiveness was intended, only a poke at parts store clerks! Sorry to derail the post. If it helps...my 18"X9.5" rear are 4.5" bs and the 18"X8" fronts are 4" bs. 4" drop springs back, 2.5 spindles front. __________________ 71 GMC 1500 LWB

01-09-2011, 12:18 AM	#14
stefan New Member Join Date: Sep 2006 Location: texas Posts: 118	Re: Backspacing in 71-72 Hey Lolife you have always given me good advice,so lets do mine im about to buy wheels in i hope a month,my truck is a 5.5 front and 8 inch in the rear and i want 17 or 18 inch wheels 8.5 in front and 10 inch in the rear and the truck is a 72 swb,thanks bud

01-09-2011, 12:25 AM	#16
72BlckButy Tot Roddin' Join Date: Apr 2005 Location: Mid-MO Posts: 24,461	Re: Backspacing in 71-72 If by dropped you mean staticly... how low are you? 2/4, 3/5, 4/6? With running a set of rallys, all you should need on a 4" drop in the front will be a creative grinding on the lower a-arm since you are running disc brakes. __________________ -Nate 1969 CST SWB - Project Blank Slate (4.5/6" ECE Static Drop, 6-lug disc brake upgrade (manual), Billet Specialties Vintec 20x8.5 255/40 (F) 20x10 295/40 (R), 250 I-6) 1960 AMF Skylark - Tot Roddin' (Lowered with custom frame; soon to include custom push bar and interior) 2008 Silverado CrewCab 1LT (5.3L, 3:73, 4x4, LT1, Z-71, Towing Package)

01-09-2011, 12:44 AM	#19
72BlckButy Tot Roddin' Join Date: Apr 2005 Location: Mid-MO Posts: 24,461	Re: Backspacing in 71-72 Grind the a-arm. Refer to: http://67-72chevytrucks.com/vboard/s...4&postcount=61 Please provide enough information when asking for assistance; it really helps to determine everything that is involved. __________________ -Nate 1969 CST SWB - Project Blank Slate (4.5/6" ECE Static Drop, 6-lug disc brake upgrade (manual), Billet Specialties Vintec 20x8.5 255/40 (F) 20x10 295/40 (R), 250 I-6) 1960 AMF Skylark - Tot Roddin' (Lowered with custom frame; soon to include custom push bar and interior) 2008 Silverado CrewCab 1LT (5.3L, 3:73, 4x4, LT1, Z-71, Towing Package) Last edited by 72BlckButy; 01-09-2011 at 12:45 AM.

01-09-2011, 12:56 AM	#21
72BlckButy Tot Roddin' Join Date: Apr 2005 Location: Mid-MO Posts: 24,461	Re: Backspacing in 71-72 Everything that lolife99 posted above is covered in the following two threads: Project NO-Life: http://67-72chevytrucks.com/vboard/s...hlight=no-life Project Blank Slate: http://67-72chevytrucks.com/vboard/s...d.php?t=353633 __________________ -Nate 1969 CST SWB - Project Blank Slate (4.5/6" ECE Static Drop, 6-lug disc brake upgrade (manual), Billet Specialties Vintec 20x8.5 255/40 (F) 20x10 295/40 (R), 250 I-6) 1960 AMF Skylark - Tot Roddin' (Lowered with custom frame; soon to include custom push bar and interior) 2008 Silverado CrewCab 1LT (5.3L, 3:73, 4x4, LT1, Z-71, Towing Package)



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