20's?? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

FnLow69 · 10-21-2005, 12:42 AM

will a 20X8.5 with a 5.4" backspacing work on my back 69 GMC that has a disc brake/ 2.5 in drop spindle conversion, i wanna lay frame so i well be Zing the frame. will that backspacing work? There centerline Smoothies. also what size tire will fit and be under 27 inches tall? any help is apperciate. thanks

**N2TRUX** · 10-21-2005, 08:58 AM

I can't help you on your back space issue since I'm not familiar with the clearence on your 69. I can offer a couple of good tire sizing calculators that will allow you to answer your tire questions-

Tire Calclator

Another one

67Fleet · 10-23-2005, 09:04 PM

Quote:

Originally Posted by FnLow69

will a 20X8.5 with a 5.4" backspacing work on my back 69 GMC that has a disc brake/ 2.5 in drop spindle conversion, i wanna lay frame so i well be Zing the frame. will that backspacing work? There centerline Smoothies. also what size tire will fit and be under 27 inches tall? any help is apperciate. thanks

They'll work ok up front but not out back. I've got same size wheels w/ 5.25" BS and disc conv. up front as well. They are fine up front but too much BS for the rear. I'm going to have to get 1" spacers out back. They're rubbing the inner fenderwells in the corners. NOT GOOD. For tires you can run 255/35/20.

FnLow69 · 10-23-2005, 10:41 PM

hey thanks for the answer guys, as for the rubbing issue Iam going to make custom wheeltubs so theres no problem there. how tall is a 255/35/20??thanks for the help

BigSky71 · 10-31-2005, 07:13 PM

Using the link from N2TRUX:

255/35/20

Section Width: 10.03 in 255 mm

Rim Diameter: 20 in 508 mm
Rim Width Range: 8.5 - 10 in
Overall Diameter: 27.02 in 686.30 mm
Sidewall Height: 3.51 in 89.154 mm
Radius: 13.51 in 343.15 mm
Circumference: 84.88 in 2155.9 mm
Revs per Mile: 769.8

67Fleet · 10-31-2005, 09:39 PM

Quote:

Originally Posted by FnLow69

hey thanks for the answer guys, as for the rubbing issue Iam going to make custom wheeltubs so theres no problem there. how tall is a 255/35/20??thanks for the help

The problem is with that much backspacing they will be "over" tucked. Mine at 5-1/4" bs sat inside the fender lip by over 2". it looked retarded.

10-21-2005, 12:42 AM	#1
FnLow69 Registered User Join Date: May 2005 Location: Washington Posts: 848	20's?? will a 20X8.5 with a 5.4" backspacing work on my back 69 GMC that has a disc brake/ 2.5 in drop spindle conversion, i wanna lay frame so i well be Zing the frame. will that backspacing work? There centerline Smoothies. also what size tire will fit and be under 27 inches tall? any help is apperciate. thanks

10-21-2005, 08:58 AM	#2
N2TRUX Happy to be here Join Date: Mar 2000 Location: Cypress, TX Posts: 39,023	Re: 20's?? I can't help you on your back space issue since I'm not familiar with the clearence on your 69. I can offer a couple of good tire sizing calculators that will allow you to answer your tire questions- Tire Calclator Another one __________________ Follow me on Facebook and Instagram @N2trux.com Articles- "Jake" the 84 to 74 crewcab "Elwood" the77_Remix 85 GMC Sierra "Scarlett" "Refining Sierra"

10-23-2005, 10:41 PM	#4
FnLow69 Registered User Join Date: May 2005 Location: Washington Posts: 848	Re: 20's?? hey thanks for the answer guys, as for the rubbing issue Iam going to make custom wheeltubs so theres no problem there. how tall is a 255/35/20??thanks for the help

10-31-2005, 07:13 PM	#5
BigSky71 LAIDOUT Join Date: Jan 2005 Location: NW Montana Posts: 928	Re: 20's?? Using the link from N2TRUX: 255/35/20 Section Width: 10.03 in 255 mm Rim Diameter: 20 in 508 mm Rim Width Range: 8.5 - 10 in Overall Diameter: 27.02 in 686.30 mm Sidewall Height: 3.51 in 89.154 mm Radius: 13.51 in 343.15 mm Circumference: 84.88 in 2155.9 mm Revs per Mile: 769.8 __________________ 67 2wd Shorty Build Pictures Last edited by BigSky71; 10-31-2005 at 07:14 PM.



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