What backspacing is needed on 20's? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

GreyHoundSteve · 12-23-2004, 02:59 PM

I am looking for rims for my truck and i was wondering what i need to look for when buying rims? I guess all GM 6 lug paterns are the same right? If i have front disc and rear drum brakes and 2 1/2 dropped spindals on a 4/6 drop and want to run 20's with 40 series sidewall tires then how wide of rims can i go and what backspacing is needed? Is there anything else im forgetting? I'd like to run 20x8 in front and 20x10 in back but dont want any rub ever, is this possible?

SCOTI · 12-23-2004, 04:03 PM

How about 20x8's w/5" back spacing & a 245-40 tire up front & 20x10's w/5" back spacing & a 295-40 for the rear.

GreyHoundSteve · 12-23-2004, 04:27 PM

Quote:

Originally Posted by SCOTI

How about 20x8's w/5" back spacing & a 245-40 tire up front & 20x10's w/5" back spacing & a 295-40 for the rear.

So 5" of backspacing will work for the front and back? If i went with a 22x10 in the back would a 6" back spacing will be okay? I dont want my rims sticking out the wheel well. One last question about rims before i make the call and get some....... If i go with a 22X10 in the rear what tire would i need to look right with a 245-40-20 up front?

grnddwn · 12-23-2004, 06:35 PM

How low is the truck. The lower it is the less room you have for rim width.

GreyHoundSteve · 12-23-2004, 06:38 PM

oops sorry 4/6 drop

bagged72blaz · 12-23-2004, 06:50 PM

Don't you have 5 lug if you have front disks.

I was also curious about this same thing. But I'm going to run the same size tires and wheels allround. That way I can rotate tires properly, and tires last longer. I'm bagged with 2" dropped lower arms, and CCP c-notch in the rear. I'm thinking of 20"/8.5" or 9" So saying that I'd need 4" back spacing or 4 1/2" respectively correct. With 20's you can have more front backspacing with out wheel rubbing on the suspension right. I'm going to remove the inner fenders. I'd like to be able to turn lock to lock aired out. I can turn lock to lock now with 17"X8" with 245/55/17 Also I'm tring to avoid rubbing in the rear when I'm going side to side also. It does now. I'm most likely going to have to do a small tub in the rear. If so I'll use stock rear fenders to do the tub.

I want 8.5" wide but these wheels are nice, and cheap but only come in 9"

BK · 12-24-2004, 09:39 PM

he could have the front disk conversion for 6 lugs

GreyHoundSteve · 12-25-2004, 05:22 PM

Quote:

Originally Posted by DroppedChoppedPanel

he could have the front disk conversion for 6 lugs

You are correct sir. I just ordered the front rotors for the 6 lug and has them cross drilled. They were only $258 from cpp.

I still need help on the sizes guys. If i have a 4/6 drop and want to run 20x8.5 in front and 22X10 in back what backspacing will i need with what tire combo? I was wanting to use 40 series sidewalls. Is this possible without having any rubbing or tubbing?

12-23-2004, 02:59 PM	#1
GreyHoundSteve Registered User Join Date: Oct 2004 Location: DFW TX Posts: 769	What backspacing is needed on 20's? I am looking for rims for my truck and i was wondering what i need to look for when buying rims? I guess all GM 6 lug paterns are the same right? If i have front disc and rear drum brakes and 2 1/2 dropped spindals on a 4/6 drop and want to run 20's with 40 series sidewall tires then how wide of rims can i go and what backspacing is needed? Is there anything else im forgetting? I'd like to run 20x8 in front and 20x10 in back but dont want any rub ever, is this possible?

12-23-2004, 04:03 PM	#2
SCOTI Registered User Join Date: Apr 2001 Location: DALLAS,TX Posts: 22,064	How about 20x8's w/5" back spacing & a 245-40 tire up front & 20x10's w/5" back spacing & a 295-40 for the rear. __________________ 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.*

12-23-2004, 06:50 PM	#6
bagged72blaz Got L.E.D.s Join Date: Dec 2004 Location: Craig Co. Posts: 195	Don't you have 5 lug if you have front disks. I was also curious about this same thing. But I'm going to run the same size tires and wheels allround. That way I can rotate tires properly, and tires last longer. I'm bagged with 2" dropped lower arms, and CCP c-notch in the rear. I'm thinking of 20"/8.5" or 9" So saying that I'd need 4" back spacing or 4 1/2" respectively correct. With 20's you can have more front backspacing with out wheel rubbing on the suspension right. I'm going to remove the inner fenders. I'd like to be able to turn lock to lock aired out. I can turn lock to lock now with 17"X8" with 245/55/17 Also I'm tring to avoid rubbing in the rear when I'm going side to side also. It does now. I'm most likely going to have to do a small tub in the rear. If so I'll use stock rear fenders to do the tub. I want 8.5" wide but these wheels are nice, and cheap but only come in 9" __________________ Bagged 1972 2wd Blazer http://www.earlyclassic.com/home.aspx Last edited by bagged72blaz; 12-23-2004 at 07:02 PM.

12-23-2004, 06:35 PM	#4
grnddwn belly dragger Join Date: Feb 2002 Location: sherwood park AB. Canada Posts: 694	How low is the truck. The lower it is the less room you have for rim width.

12-23-2004, 06:38 PM	#5
GreyHoundSteve Registered User Join Date: Oct 2004 Location: DFW TX Posts: 769	oops sorry 4/6 drop

12-24-2004, 09:39 PM	#7
BK BK Built Join Date: Aug 2004 Location: Oroville, WA Posts: 478	he could have the front disk conversion for 6 lugs



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