Coys Backspacing Question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

dhart · 12-31-2009, 11:36 AM

I have a 72 c/10 that is lowered, drop spindles and 2 inch lower springs in the front, 5 inch springs rear, adj trac bar, shock relocators, sway bars etc. The truck has all stock width as far as control arms and rear diff and it has the inner fenders.
I currently have a set of 17 inch TTII's 17x8 & 17X9.5 with 255/50/17 & 275/50/17 inch Nittos.
I am wanting to put a set of Coys C-5 20 inch wheels on it, and i am needing some help and or pics of backspace reccomendations for a 20X10 inch rear and 20X8 front.
It seems that the rear spec seems to be 20X10 with a 5' inch BS but i know a bunch of peaple disagree on the front.

SCOTI · 12-31-2009, 12:07 PM

20x8.5" Coys come w/either 4.75 or 5.25" back-spacing (they don't make a 8" width in the 20's). The 5.25" tucks the tire so it doesn't rub the outer lip on lowered trucks. The 71-72's had the slightly wider rear housing vs earlier 12-bolts. The 20x10's are currently only offered in either 5.0 or 5.5" back-spacing. The 5.50" BS would work better on the wider rear housing.

dhart · 12-31-2009, 12:56 PM

Thanks for the reply. I guess i just need to figure out if the fronts will rub for sure with a wider backspacing, (20X8.5 with 4 3/4 BS) vs 5 1/4 BS

I spoke with a couple of people running the wider backspacing (20x10 5 inch BS) on the rear and i really like how they come right to the edge of the bedside. I wonder if this is the right Backspace for 72 model and if there will be some kind of wheel well mod to not rub.

I am likely going to bag the truck too, but keeping the stock bed height and inner fenders, that way i can go a bit lower than it is already with a bit better ride quality.

i have seen a lot of pics of the setup i like, but i just want to be sure what the offsets are, i was going to run 18's on the front but i think the 20's all the way around look a bit better but if it is going to suck on rubbing and ride quality i will just stick with an 18 20 stagger.

I know a couple of members have the coys setup with 20's i just need to see what width and offsets they have found to work best.

Thanks so much for the help, i am going to post some pics of O'l Blue tonight if i have time.

big_al_71 · 12-31-2009, 01:10 PM

I cant help you with the front as I went wityh 18's but in the back I have
20x10 with a 5 1/2 inch back space and it fills the wheel tub completely and I have six inch rear lowering springs with a 295-40-20 tire.

12-31-2009, 11:36 AM	#1
dhart Registered User Join Date: Dec 2009 Location: Memphis TN Posts: 102	Coys Backspacing Question I have a 72 c/10 that is lowered, drop spindles and 2 inch lower springs in the front, 5 inch springs rear, adj trac bar, shock relocators, sway bars etc. The truck has all stock width as far as control arms and rear diff and it has the inner fenders. I currently have a set of 17 inch TTII's 17x8 & 17X9.5 with 255/50/17 & 275/50/17 inch Nittos. I am wanting to put a set of Coys C-5 20 inch wheels on it, and i am needing some help and or pics of backspace reccomendations for a 20X10 inch rear and 20X8 front. It seems that the rear spec seems to be 20X10 with a 5' inch BS but i know a bunch of peaple disagree on the front.

12-31-2009, 12:07 PM	#2
SCOTI Registered User Join Date: Apr 2001 Location: DALLAS,TX Posts: 22,027	Re: Coys Backspacing Question 20x8.5" Coys come w/either 4.75 or 5.25" back-spacing (they don't make a 8" width in the 20's). The 5.25" tucks the tire so it doesn't rub the outer lip on lowered trucks. The 71-72's had the slightly wider rear housing vs earlier 12-bolts. The 20x10's are currently only offered in either 5.0 or 5.5" back-spacing. The 5.50" BS would work better on the wider rear housing. __________________ 67SWB-B.B.RetroRod 64SWB-Recycle 89CCDually-Driver/Tow Truck 99CCSWB Driver All Fleetsides @rattlecankustoms in IG Building a small, high rpm engine with the perfect bore, stroke and rod ratio is very impressive. It's like a highly skilled Morrocan sword fighter with a Damascus Steel Scimitar..... *Cubic inches is like Indiana Jones with a cheap pistol.*

12-31-2009, 12:56 PM	#3
dhart Registered User Join Date: Dec 2009 Location: Memphis TN Posts: 102	Re: Coys Backspacing Question Thanks for the reply. I guess i just need to figure out if the fronts will rub for sure with a wider backspacing, (20X8.5 with 4 3/4 BS) vs 5 1/4 BS I spoke with a couple of people running the wider backspacing (20x10 5 inch BS) on the rear and i really like how they come right to the edge of the bedside. I wonder if this is the right Backspace for 72 model and if there will be some kind of wheel well mod to not rub. I am likely going to bag the truck too, but keeping the stock bed height and inner fenders, that way i can go a bit lower than it is already with a bit better ride quality. i have seen a lot of pics of the setup i like, but i just want to be sure what the offsets are, i was going to run 18's on the front but i think the 20's all the way around look a bit better but if it is going to suck on rubbing and ride quality i will just stick with an 18 20 stagger. I know a couple of members have the coys setup with 20's i just need to see what width and offsets they have found to work best. Thanks so much for the help, i am going to post some pics of O'l Blue tonight if i have time.

12-31-2009, 01:10 PM	#4
big_al_71 Registered User Join Date: Jun 2008 Location: South Florida Posts: 11,375	Re: Coys Backspacing Question I cant help you with the front as I went wityh 18's but in the back I have 20x10 with a 5 1/2 inch back space and it fills the wheel tub completely and I have six inch rear lowering springs with a 295-40-20 tire. Attached Images __________________ Get your facts first, and then you can distort them as much as you please!!!!!. Sylvester's build thread >>>http://67-72chevytrucks.com/vboard/s...ht=big+rebuild Last edited by big_al_71; 12-31-2009 at 01:10 PM.



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